U.S. patent application number 10/387525 was filed with the patent office on 2004-02-05 for expression of exogenous polynucleotide sequences in a vertebrate.
This patent application is currently assigned to Vical Incorporated. Invention is credited to Carson, Dennis A., Felgner, Philip L., Malone, Robert Wallace, Rhodes, Gary H., Wolff, Jon Asher.
Application Number | 20040023911 10/387525 |
Document ID | / |
Family ID | 27406452 |
Filed Date | 2004-02-05 |
United States Patent
Application |
20040023911 |
Kind Code |
A1 |
Felgner, Philip L. ; et
al. |
February 5, 2004 |
Expression of exogenous polynucleotide sequences in a
vertebrate
Abstract
A method for delivering a naked or isolated polynucleotide to
the interior of a cell in a vertebrate, comprising the interstitial
introduction of a naked polynucleotide into a tissue of the
vertebrate where the polynucleotide is taken up by the cells of the
tissue and exerts a therapeutic effect on the vertebrate. The
method can be used to deliver a therapeutic polypeptide to the
cells of the vertebrate, to provide an immune response upon in vivo
translation of the polynucleotide, to deliver antisense
polynucleotides, to deliver receptors to the cells of the
vertebrate, or to provide transitory gene therapy.
Inventors: |
Felgner, Philip L.; (Rancho
Santa Fe, CA) ; Wolff, Jon Asher; (Madison, WI)
; Rhodes, Gary H.; (Leucadia, CA) ; Malone, Robert
Wallace; (Chicago, IL) ; Carson, Dennis A.;
(Del Mar, CA) |
Correspondence
Address: |
STERNE, KESSLER, GOLDSTEIN & FOX PLLC
1100 NEW YORK AVENUE, N.W.
WASHINGTON
DC
20005
US
|
Assignee: |
Vical Incorporated
Wisconsin Alumni Research Foundation
|
Family ID: |
27406452 |
Appl. No.: |
10/387525 |
Filed: |
March 14, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10387525 |
Mar 14, 2003 |
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09452872 |
Dec 2, 1999 |
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09452872 |
Dec 2, 1999 |
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08481919 |
Jun 7, 1995 |
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6214804 |
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08481919 |
Jun 7, 1995 |
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07496991 |
Mar 21, 1990 |
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07496991 |
Mar 21, 1990 |
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07467881 |
Jan 19, 1990 |
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07467881 |
Jan 19, 1990 |
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07326305 |
Mar 21, 1989 |
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Current U.S.
Class: |
514/44A |
Current CPC
Class: |
A61K 9/1272 20130101;
C12N 9/78 20130101; C07K 14/61 20130101; C12N 9/1247 20130101; C12N
2740/16122 20130101; C12Y 113/12007 20130101; C12N 15/87 20130101;
C12N 9/0069 20130101; C12N 9/1033 20130101; C07K 14/005 20130101;
A61K 48/00 20130101 |
Class at
Publication: |
514/44 |
International
Class: |
A61K 048/00 |
Claims
What is claimed is:
1. A pharmaceutical product, comprising: naked polynucleotide,
operatively coding for a biologically active polypeptide, in
physiologically acceptable administrable form, in a container; and
a notice associated with said container in form prescribed by a
governmental agency regulating the manufacture, use, or sale of
pharmaceuticals, which notice is reflective of approval by said
agency of said form of said polynucleotide for human or veterinary
administration.
2. A pharmaceutical product, comprising: naked polynucleotide,
operatively coding for a biologically active peptide, in solution
in a physiologically acceptable injectable carrier and suitable for
introduction interstitially into a tissue to cause cells of said
tissue to express said polypeptide; a container enclosing said
solution; and a notice associated with said container in form
prescribed by a governmental agency regulating the manufacture,
use, or sale of pharmaceuticals, which notice is reflective of
approval by said agency of manufacture, use, or sale of said
solution of polynucleotide for human or veterinary
administration.
3. The product of claim 2, wherein said peptide is immunogenic and
administration of said solution to a human serves to vaccinate said
human.
4. The product of claim 2, wherein said peptide is therapeutic and
administration of said solution to a human in need of therapy
relating to said polypeptide has a therapeutic effect.
5. A pharmaceutical product for treatment of muscular dystrophy,
comprising: a sterile, pharmaceutically acceptable carrier; a
pharmaceutically effective amount of a naked polynucleotide
operatively coding for dystrophin solubilized in said carrier; and
a container enclosing said carrier and said polynucleotide in
sterile fashion.
6. The product of claim 5, wherein said polynucleotide is DNA.
7. A pharmaceutical product for use in supplying a biologically
active polypeptide to a vertebrate, comprising: a pharmaceutically
effective amount of a naked polynucleotide operatively coding for
said polypeptide; a container enclosing said polynucleotide in a
sterile fashion; and means associated with said container for
permitting transfer of said polynucleotide from said container to
the interstitial space of a tissue, whereby cells of said tissue
can take up and express said polynucleotide.
8. The product of claim 7, wherein said container is a syringe.
9. The product of claim 7, wherein the amount of said
polynucleotide in said container is at least 5 micrograms.
10. A pharmaceutical product for use in immunizing a vertebrate,
comprising: a pharmaceutically effective amount of a naked
polynucleotide operatively coding for an immunogenic polypeptide; a
sealed container enclosing said polynucleotide in a sterile
fashion; and means associated with said container for permitting
transfer of said polynucleotide from said container to the
interstitial space of a tissue, whereby cells of said tissue can
take up and express said polynucleotide.
11. The product of claim 10, wherein said container is a
syringe.
12. The method of claim 10, wherein the amount of said
polynucleotide in said container is at least 5 micrograms.
13. A method for delivering a pharmaceutical or immunogenic
polypeptide to the interior of a cell of a vertebrate in vivo,
comprising the step of: introducing a preparation comprising a
pharmaceutically acceptable injectable carrier and a naked
polynucleotide operatively coding for said polypeptide into the
interstitial space of a tissue comprising said cell, whereby said
naked polynucleotide is taken up into the interior of said cell and
has an immunogenic or pharmacological effect on said
vertebrate.
14. The method of claim 13, wherein said polypeptide is immunogenic
and said vertebrate develops an immune response to said
polypeptide.
15. The method of claim 13, wherein said polypeptide is
therapeutic.
16. The method of claim 13, wherein said polynucleotide is
mRNA.
17. The method of claim 13, wherein said polynucleotide is DNA.
18. The method of claim 13, wherein said polynucleotide is a DNA
sequence incorporated into a plasmid vector and said plasmid vector
further comprises a replicator.
19. The method of claim 13, wherein said DNA sequence contains a
promoter sequence.
20. The method of claim 19, wherein said promoter is a
cell-specific promoter that permits substantial transcription of
DNA only in predetermined cells.
21. The method of claim 13, wherein said polynucleotide sequence
contains a sequence operatively coding for the secretion of said
polypeptide.
22. The method of claim 13, wherein said polypeptide expression is
transitory.
23. The method of claim 13, wherein said polypeptide is an
enzyme.
24. The method of claim 13, wherein said polypeptide is an
hormone.
25. The method of claim 13, wherein said polypeptide is a
lymphokine.
26. The method of claim 13, wherein said polypeptide is a cell
surface receptor.
27. The method of claim 13, wherein said polypeptide is a growth
factor.
28. The method of claim 13, wherein said polypeptide is a
regulatory protein.
29. The method of claim 13, wherein said polynucleotide is
incorporated into muscle cells.
30. The method of claim 13, wherein said preparation is injected
intramuscularly.
31. The method of claim 13, wherein said polynucleotide is
incorporated into cells of skin, brain, lung, liver, spleen or
blood.
32. The method of claim 13, wherein said preparation is injected
intradermally, subdermally, intrathecally, or intravenously.
33. The method of claim 13, wherein said preparation is impressed
into the skin.
34. The method of claim 13, wherein said preparation is delivered
transdermally.
35. The method of claim 13, wherein said polynucleotide is a
non-replicating DNA sequence operatively coding for said
polypeptide and for a polymerase for transcribing said DNA, and
wherein said DNA includes recognition sites for said polymerase,
and said injectable preparation further includes a means for
providing an initial quantity of said polymerase in said cell.
36. The method of claim 35, wherein said polymerase is phage T7
polymerase and said recognition site is a T7 origin of replication
sequence.
37. A method for treating a disease associated with the deficiency
or absence of a specific polypeptide in a vertebrate, comprising
the step of: introducing an injectable preparation comprising a
pharmaceutically acceptable carrier and containing a naked
polynucleotide operatively coding for said polypeptide into a
vertebrate and permitting said polynucleotide to be incorporated
into a cell, wherein said polypeptide is formed as the translation
product of said polynucleotide and said deficiency or absence of
said polypeptide is effectively treated.
38. The method of claim 37, wherein said preparation is injected
into muscle.
39. The method of claim 37, wherein said cell is a persistent
non-dividing cell.
40. A therapy for phenylketonuria according to the method set forth
in claim 37, wherein said polynucleotide codes for the polypeptide
phenylalanine hydroxylase.
41. The method of claim 37, wherein said polynucleotide codes for
human growth hormone.
42. A therapy for hypercholesterolemia according to the method set
forth in claim 37, wherein a polynucleotide operatively coding for
a receptor involved in cholesterol homeostasis is incorporated into
a hepatocyte, whereby said receptor is expressed by said cell.
43. A method for immunizing a vertebrate, comprising the step of:
introducing an injectable preparation comprising a pharmaceutically
acceptable carrier and a naked, expressible polynucleotide
operatively coding for an immunogenic peptide interstitially into
tissue of a vertebrate whereby an immunogenic translation product
of said polynucleotide is formed by a cell of said tissue, thereby
eliciting an immune response against said immunogen.
44. The method of claim 43, wherein said immunogenic translation
product is presented by said cell in the context of the major
histocompatibility complex.
45. The method of claim 43, wherein said cells are muscle
cells.
46. The method of claim 43, wherein said injectable preparation
further comprises an adjuvant or a lymphokine.
47. The method of claim 43, wherein said immunogenic translation
product is presented by a cell and provokes a humoral immune
response, comprising the synthesis of antibody.
48. The method of claim 43, wherein said cell expresses major
histocompatibility antigens of Class I, and said immunogenic
peptide is presented in the context of Class I histocompatibility
antigens and wherein said immune response is cellular and comprises
the production of cytotoxic T-cells.
49. A method for introducing a polynucleotide into muscle cells in
vivo, comprising the steps of: providing a composition comprising a
naked polynucleotide in a pharmaceutically acceptable carrier; and
contacting said composition with muscle tissue of a vertebrate in
vivo, whereby said polynucleotide is introduced into muscle cells
of said tissue.
50. The method of claim 49, wherein said polynucleotide is an
antisense polynucleotide.
51. The method of claim 49, wherein said polynucleotide codes for a
therapeutic peptide that is expressed by said muscle cells after
said contacting step to provide therapy to said vertebrate.
52. The method of claim 49, wherein said polynucleotide codes for
an immunogenic peptide that is expressed by said muscle cells after
said contacting step and which generates an immune response,
thereby immunizing said vertebrate.
53. A method for obtaining long term administration of a
polypeptide to a vertebrate, comprising the step of introducing a
naked DNA sequence operatively coding for said polypeptide
interstitially into tissue of said vertebrate, whereby cells of
said tissue produce said polypeptide for at least 3 months.
54. The method of claim 53, wherein said cells producing said
polypeptide are nonproliferating cells.
55. The method of claim 54, wherein said cells are muscle
cells.
56. A method for obtaining transitory expression of a polypeptide
in a vertebrate, comprising the step of introducing a naked mRNA
sequence operatively coding for said polypeptide interstitially
into tissue of said vertebrate, whereby cells of said tissue
produce said polypeptide for less than about 10 days.
57. The method of claim 56, wherein said tissue is solid
tissue.
58. A method for treatment of muscular dystrophy, comprising the
steps of: introducing a therapeutic amount of a composition
comprising a polynucleotide operatively coding for dystrophin in a
pharmaceutically acceptable carrier in vivo into muscle tissue of
an animal suffering from muscular dystrophy, whereby said
polynucleotide is taken up into cells of said tissue and dystrophin
is produced in vivo.
59. The method of claim 58, wherein said composition is introduced
by means of injection.
60. The method of claim 58, wherein said polynucleotide is a naked
polynucleotide and said composition is introduced interstitially
into said muscle tissue.
61. A pharmaceutical product, comprising: naked antisense
polynucleotide in physiologically acceptable administrable form, in
a container; and a notice associated with said container in form
prescribed by a governmental agency regulating the manufacture,
use, or sale of pharmaceuticals, which notice is reflective of
approval by said agency of said form of said polynucleotide for
human or veterinary administration.
62. Use of naked polynucleotide operatively coding for a
physiologically active polypeptide in the preparation of a
pharmaceutical for introduction interstitially into tissue to cause
cells comprising said tissue to produce said polypeptide.
63. Use according to claim 62, wherein said pharmaceutical is for
introduction into muscle tissue whereby muscle cells produce said
polypeptide.
64. Use according to claim 62, wherein said peptide is dystrophin
and said pharmaceutical is for treatment of muscular dystrophy.
65. Use of naked antisense polynucleotide in the preparation of a
pharmaceutical for introduction interstitially into tissue of a
vertebrate to inhibit translation of polynucleotide in cells of
said vertebrate.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 09/452,872, filed Dec. 2, 1999, now allowed; which is a
continuation of U.S. application Ser. No. 08/481,919, filed Jun. 7,
1995, now U.S. Pat. No. 6,214,804, issued Apr. 10, 2001; which is a
continuation of U.S. application Ser. No. 07/496,991, filed Mar.
21, 1990, now abandoned; which is a continuation-in-part of U.S.
application Ser. No. 07/467,881, filed Jan. 19, 1990, now
abandoned; which is a continuation-in-part of U.S. application Ser.
No. 07/326,305, filed Mar. 21, 1989, now abandoned; each of the
foregoing disclosures is fully incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to introduction of naked DNA
and RNA sequences into a vertebrate to achieve controlled
expression of a polypeptide. It is useful in gene therapy,
vaccination, and any therapeutic situation in which a polypeptide
should be administered to cells in vivo.
[0004] 2. Related Art
[0005] Current research in gene therapy has focused on "permanent"
cures, in which DNA is integrated into the genome of the patient.
Viral vectors are presently the most frequently used means for
transforming the patient's cells and introducing DNA into the
genome. In an indirect method, viral vectors, carrying new genetic
information, are used to infect target cells removed from the body,
and these cells are then re-implanted. Direct in vivo gene transfer
into postnatal animals has been reported for formulations of DNA
encapsulated in liposomes and DNA entrapped in proteoliposomes
containing viral envelope receptor proteins (Nicolau et al., Proc.
Natl. Acad Sci USA 80:1068-1072 (1983); Kaneda et al., Science
243:375-378 (1989); Mannino et al., Biotechniques 6:682-690 (1988).
Positive results have also been described with calcium phosphate
co-precipitated DNA (Benvenisty and Reshef Proc. Natl. Acad Sci USA
83:9551-9555 (1986)).
[0006] The clinical application of gene therapy, as well as the
utilization of recombinant retrovirus vectors, has been delayed
because of safety considerations. Integration of exogenous DNA into
the genome of a cell can cause DNA damage and possible genetic
changes in the recipient cell that could predispose to malignancy.
A method which avoids these potential problems would be of
significant benefit in making gene therapy safe and effective.
[0007] Vaccination with immunogenic proteins has eliminated or
reduced the incidence of many diseases; however there are major
difficulties in using proteins associated with other pathogens and
disease states as immunogens. Many protein antigens are not
intrinsically immunogenic. More often, they are not effective as
vaccines because of the manner in which the immune system
operates.
[0008] The immune system of vertebrates consists of several
interacting components. The best characterized and most important
parts are the humoral and cellular (cytolytic) branches. Humoral
immunity involves antibodies, proteins which are secreted into the
body fluids and which directly recognize an antigen. The cellular
system, in contrast, relies on special cells which recognize and
kill other cells which are producing foreign antigens. This basic
functional division reflects two different strategies of immune
defense. Humoral immunity is mainly directed at antigens which are
exogenous to the animal whereas the cellular system responds to
antigens which are actively synthesized within the animal.
[0009] Antibody molecules, the effectors of humoral immunity, are
secreted by special B lymphoid cells, B cells, in response to
antigen. Antibodies can bind to and inactivate antigen directly
(neutralizing antibodies) or activate other cells of the immune
system to destroy the antigen.
[0010] Cellular immune recognition is mediated by a special class
of lymphoid cells, the cytotoxic T cells. These cells do not
recognize whole antigens but instead they respond to degraded
peptide fragments thereof which appear on the surface of the target
cell bound to proteins called class I major histocompatibility
complex (MHC) molecules. Essentially all nucleated cells have class
I molecules. It is believed that proteins produced within the cell
are continually degraded to peptides as part of normal cellular
metabolism. These fragments are bound to the MHC molecules and are
transported to the cell surface. Thus the cellular immune system is
constantly monitoring the spectra of proteins produced in all cells
in the body and is poised to eliminate any cells producing foreign
antigens.
[0011] Vaccination is the process of preparing an animal to respond
to an antigen. Vaccination is more complex than immune recognition
and involves not only B cells and cytotoxic T cells but other types
of lymphoid cells as well. During vaccination, cells which
recognize the antigen (B cells or cytotoxic T cells) are clonally
expanded. In addition, the population of ancillary cells (helper T
cells) specific for the antigen also increase. Vaccination also
involves specialized antigen presenting cells which can process the
antigen and display it in a form which can stimulate one of the two
pathways.
[0012] Vaccination has changed little since the time of Louis
Pasteur. A foreign antigen is introduced into an animal where it
activates specific B cells by binding to surface immunoglobulins.
It is also taken up by antigen processing cells, wherein it is
degraded, and appears in fragments on the surface of these cells
bound to Class II MHC molecules. Peptides bound to class II
molecules are capable of stimulating the helper class of T cells.
Both helper T cells and activated B cells are required to produce
active humoral immunization. Cellular immunity is thought to be
stimulated by a similar but poorly understood mechanism.
[0013] Thus two different and distinct pathways of antigen
processing produce exogenous antigens bound to class II MHC
molecules where they can stimulate T helper cells, as well as
endogenous proteins degraded and bound to class I MHC molecules and
recognized by the cytotoxic class of T cells. There is little or no
difference in the distribution of MHC molecules. Essentially all
nucleated cells express class I molecules whereas class II MHC
proteins are restricted to some few types of lymphoid cells.
[0014] Normal vaccination schemes will always produce a humoral
immune response. They may also provide cytotoxic immunity. The
humoral system protects a vaccinated individual from subsequent
challenge from a pathogen and can prevent the spread of an
intracellular infection if the pathogen goes through an
extracellular phase during its life cycle; however, it can do
relatively little to eliminate intracellular pathogens. Cytotoxic
immunity complements the humoral system by eliminating the infected
cells. Thus effective vaccination should activate both types of
immunity.
[0015] A cytotoxic T cell response is necessary to remove
intracellular pathogens such as viruses as well as malignant cells.
It has proven difficult to present an exogenously administered
antigen in adequate concentrations in conjunction with Class I
molecules to assure an adequate response. This has severely
hindered the development of vaccines against tumor-specific
antigens (e.g., on breast or colon cancer cells), and against
weakly immunogenic viral proteins (e.g., HIV, Herpes, non-A, non-B
hepatitis, CMV and EBV).
[0016] It would be desirable to provide a cellular immune response
alone in immunizing against agents such as viruses for which
antibodies have been shown to enhance infectivity. It would also be
useful to provide such a response against both chronic and latent
viral infections and against malignant cells.
[0017] The use of synthetic peptide vaccines does not solve these
problems because either the peptides do not readily associate with
histocompatibility molecules, have a short serum half-life, are
rapidly proteolyzed, or do not specifically localize to
antigen-presenting monocytes and macrophages. At best, all
exogenously administered antigens must compete with the universe of
self-proteins for binding to antigen-presenting macrophages.
[0018] Major efforts have been mounted to elicit immune responses
to poorly immunogenic viral proteins from the herpes viruses,
non-A, non-B hepatitis, HIV, and the like. These pathogens are
difficult and hazardous to propagate in vitro. As mentioned above,
synthetic peptide vaccines corresponding to viral-encoded proteins
have been made, but have severe pitfalls. Attempts have also been
made to use vaccinia virus vectors to express proteins from other
viruses. However, the results have been disappointing, since (a)
recombinant vaccinia viruses may be rapidly eliminated from the
circulation in already immune individuals, and (b) the
administration of complex viral antigens may induce a phenomenon
known as "antigenic competition," in which weakly immunogenic
portions of the virus fail to elicit an immune response because
they are out-competed by other more potent regions of the
administered antigen.
[0019] Another major problem with protein or peptide vaccines is
anaphylactic reaction which can occur when injections of antigen
are repeated in efforts to produce a potent immune response. In
this phenomenon, IgE antibodies formed in response to the antigen
cause severe and sometimes fatal allergic reactions.
[0020] Accordingly, there is a need for a method for invoking a
safe and effective immune response to this type of protein or
polypeptide. Moreover, there is a great need for a method that will
associate these antigens with Class I histocompatibility antigens
on the cell surface to elicit a cytotoxic T cell response, avoid
anaphylaxis and proteolysis of the material in the serum, and
facilitate localization of the material to monocytes and
macrophages.
[0021] A large number of disease states can benefit from the
administration of therapeutic peptides. Such peptides include
lymphokines, such as interleukin-2, tumor necrosis factor, and the
interferons; growth factors, such as nerve growth factor, epidermal
growth factor, and human growth hormone; tissue plasminogen
activator; factor VIII:C; granulocyte-macrophage colony-stimulating
factor; erythropoietin; insulin; calcitonin; thymidine kinase; and
the like. Moreover, selective delivery of toxic peptides (such as
ricin, diphtheria toxin, or cobra venom factor) to diseased or
neoplastic cells can have major therapeutic benefits. Current
peptide delivery systems suffer from significant problems,
including the inability to effectively incorporate functional cell
surface receptors onto cell membranes, and the necessity of
systemically administering large quantities of the peptide (with
resultant undesirable systemic side effects) in order to deliver a
therapeutic amount of the peptide into or onto the target cell.
[0022] These above-described problems associated with gene therapy,
immunization, and delivery of therapeutic peptides to cells are
addressed by the present invention.
SUMMARY OF THE INVENTION
[0023] The present invention provides a method for delivering a
pharmaceutical or immunogenic polypeptide to the interior of a cell
of a vertebrate in vivo, comprising the step of introducing a
preparation comprising a pharmaceutically acceptable injectable
carrier and a naked polynucleotide operatively coding for the
polypeptide into the interstitial space of a tissue comprising the
cell, whereby the naked polynucleotide is taken up into the
interior of the cell and has an immunogenic or pharmacological
effect on the vertebrate. Also provided is a method for introducing
a polynucleotide into muscle cells in vivo, comprising the steps of
providing a composition comprising a naked polynucleotide in a
pharmaceutically acceptable carrier, and contacting the composition
with muscle tissue of a vertebrate in vivo, whereby the
polynucleotide is introduced into muscle cells of the tissue. The
polynucleotide may be an antisense polynucleotide. Alternatively,
the polynucleotide may code for a therapeutic peptide that is
expressed by the muscle cells after the contacting step to provide
therapy to the vertebrate. Similarly, it may code for an
immunogenic peptide that is expressed by the muscle cells after the
contacting step and which generates an immune response, thereby
immunizing the vertebrate.
[0024] One particularly attractive aspect of the invention is a
method for obtaining long term administration of a polypeptide to a
vertebrate, comprising the step of introducing a naked DNA sequence
operatively coding for the polypeptide interstitially into tissue
of the vertebrate, whereby cells of the tissue produce the
polypeptide for at least one month or at least 3 months, more
preferably at least 6 months. In this embodiment of the invention,
the cells producing the polypeptide are nonproliferating cells,
such as muscle cells.
[0025] Another method according to the invention is a method for
obtaining transitory expression of a polypeptide in a vertebrate,
comprising the step of introducing a naked mRNA sequence
operatively coding for the polypeptide interstitially into tissue
of the vertebrate, whereby cells of the tissue produce the
polypeptide for less than about 20 days, usually less than about 10
days, and often less than 3 or 5 days. For many of the methods of
the invention, administration into solid tissue is preferred.
[0026] One important aspect of the invention is a method for
treatment of muscular dystrophy, comprising the steps of
introducing a therapeutic amount of a composition comprising a
polynucleotide operatively coding for dystrophin in a
pharmaceutically acceptable injectable carrier in vivo into muscle
tissue of an animal suffering from muscular dystrophy, whereby the
polynucleotide is taken up into the cells and dystrophin is
produced in vivo. Preferably, the polynucleotide is a naked
polynucleotide and the composition is introduced interstitially
into the muscle tissue.
[0027] The present invention also includes pharmaceutical products
for all of the uses contemplated in the methods described herein.
For example, there is a pharmaceutical product, comprising naked
polynucleotide, operatively coding for a biologically active
polypeptide, in physiologically acceptable administrable form, in a
container, and a notice associated with the container in form
prescribed by a governmental agency regulating the manufacture,
use, or sale of pharmaceuticals, which notice is reflective of
approval by the agency of the form of the polynucleotide for human
or veterinary administration. Such notice, for example, may be the
labeling approved by the U.S. Food and Drug Administration for
prescription drugs, or the approved product insert.
[0028] In another embodiment, the invention provides a
pharmaceutical product, comprising naked polynucleotide,
operatively coding for a biologically active peptide, in solution
in a physiologically acceptable injectable carrier and suitable for
introduction interstitially into a tissue to cause cells of the
tissue to express the polypeptide, a container enclosing the
solution, and a notice associated with the container in form
prescribed by a governmental agency regulating the manufacture,
use, or sale of pharmaceuticals, which notice is reflective of
approval by the agency of manufacture, use, or sale of the solution
of polynucleotide for human or veterinary administration. The
peptide may be immunogenic and administration of the solution to a
human may serve to vaccinate the human, or an animal. Similarly,
the peptide may be therapeutic and administration of the solution
to a vertebrate in need of therapy relating to the polypeptide will
have a therapeutic effect.
[0029] Also provided by the present invention is a pharmaceutical
product, comprising naked antisense polynucleotide, in solution in
a physiologically acceptable injectable carrier and suitable for
introduction interstitially into a tissue to cause cells of the
tissue to take up the polynucleotide and provide a therapeutic
effect, a container enclosing the solution, and a notice associated
with the container in form prescribed by a governmental agency
regulating the manufacture, use, or sale of pharmaceuticals, which
notice is reflective of approval by the agency of manufacture, use,
or sale of the solution of polynucleotide for human or veterinary
administration.
[0030] One particularly important aspect of the invention relates
to a pharmaceutical product for treatment of muscular dystrophy,
comprising a sterile, pharmaceutically acceptable carrier, a
pharmaceutically effective amount of a naked polynucleotide
operatively coding for dystrophin in the carrier, and a container
enclosing the carrier and the polynucleotide in sterile fashion.
Preferably, the polynucleotide is DNA.
[0031] From yet another perspective, the invention includes a
pharmaceutical product for use in supplying a biologically active
polypeptide to a vertebrate, comprising a pharmaceutically
effective amount of a naked polynucleotide operatively coding for
the polypeptide, a container enclosing the carrier and the
polynucleotide in a sterile fashion, and means associated with the
container for permitting transfer of the polynucleotide from the
container to the interstitial space of a tissue, whereby cells of
the tissue can take up and express the polynucleotide. The means
for permitting such transfer can include a conventional septum that
can be penetrated, e.g., by a needle. Alternatively, when the
container is a syringe, the means may be considered to comprise the
plunger of the syringe or a needle attached to the syringe.
[0032] Containers used in the present invention will usually have
at least 1, preferably at least 5 or 10, and more preferably at
least 50 or 100 micrograms of polynucleotide, to provide one or
more unit dosages. For many applications, the container will have
at least 500 micrograms or 1 milligram, and often will contain at
least 50 or 100 milligrams of polynucleotide.
[0033] Another aspect of the invention provides a pharmaceutical
product for use in immunizing a vertebrate, comprising a
pharmaceutically effective amount of a naked polynucleotide
operatively coding for an immunogenic polypeptide, a sealed
container enclosing the polynucleotide in a sterile fashion, and
means associated with the container for permitting transfer of the
polynucleotide from the container to the interstitial space of a
tissue, whereby cells of the tissue can take up and express the
polynucleotide.
[0034] Still another aspect of the present invention is the use of
naked polynucleotide operatively coding for a physiologically
active polypeptide in the preparation of a pharmaceutical for
introduction interstitially into tissue to cause cells comprising
the tissue to produce the polypeptide. The pharmaceutical, for
example, may be for introduction into muscle tissue whereby muscle
cells produce the polypeptide. Also contemplated is such use,
wherein the peptide is dystrophin and the pharmaceutical is for
treatment of muscular dystrophy.
[0035] Another use according to the invention is use of naked
antisense polynucleotide in the preparation of a pharmaceutical for
introduction interstitially into tissue of a vertebrate to inhibit
translation of polynucleotide in cells of the vertebrate.
[0036] The tissue into which the polynucleotide is introduced can
be a persistent, non-dividing cell. The polynucleotide may be
either a DNA or RNA sequence. When the polynucleotide is DNA, it
can also be a DNA sequence which is itself non-replicating, but is
inserted into a plasmid, and the plasmid further comprises a
replicator. The DNA may be a sequence engineered so as not to
integrate into the host cell genome. The polynucleotide sequences
may code for a polypeptide which is either contained within the
cells or secreted therefrom, or may comprise a sequence which
directs the secretion of the peptide.
[0037] The DNA sequence may also include a promoter sequence. In
one preferred embodiment, the DNA sequence includes a cell-specific
promoter that permits substantial transcription of the DNA only in
predetermined cells. The DNA may also code for a polymerase for
transcribing the DNA, and may comprise recognition sites for the
polymerase and the injectable preparation may include an initial
quantity of the polymerase.
[0038] In many instances, it is preferred that the polynucleotide
is translated for a limited period of time so that the polypeptide
delivery is transitory. The polypeptide may advantageously be a
therapeutic polypeptide, and may comprise an enzyme, a hormone, a
lymphokine, a receptor, particularly a cell surface receptor, a
regulatory protein, such as a growth factor or other regulatory
agent, or any other protein or peptide that one desires to deliver
to a cell in a living vertebrate and for which corresponding DNA or
mRNA can be obtained.
[0039] In preferred embodiments, the polynucleotide is introduced
into muscle tissue; in other embodiments the polynucleotide is
incorporated into tissues of skin, brain, lung, liver, spleen or
blood. The preparation is injected into the vertebrate by a variety
of routes, which may be intradermally, subdermally, intrathecally,
or intravenously, or it may be placed within cavities of the body.
In a preferred embodiment, the polynucleotide is injected
intramuscularly. In still other embodiments, the preparation
comprising the polynucleotide is impressed into the skin.
Transdermal administration is also contemplated, as is
inhalation.
[0040] In one preferred embodiment, the polynucleotide is DNA
coding for both a polypeptide and a polymerase for transcribing the
DNA, and the DNA includes recognition sites for the polymerase and
the injectable preparation further includes a means for providing
an initial quantity of the polymerase in the cell. The initial
quantity of polymerase may be physically present together with the
DNA.
[0041] Alternatively, it may be provided by including mRNA coding
therefor, which mRNA is translated by the cell. In this embodiment
of the invention, the DNA is preferably a plasmid. Preferably, the
polymerase is phage T7 polymerase and the recognition site is a T7
origin of replication sequence.
[0042] In accordance with another aspect of the invention, there is
provided a method for treating a disease associated with the
deficiency or absence of a specific polypeptide in a vertebrate,
comprising the steps of obtaining an injectable preparation
comprising a pharmaceutically acceptable injectable carrier
containing a naked polynucleotide coding for the specific
polypeptide; introducing the injectable preparation into a
vertebrate and permitting the polynucleotide to be incorporated
into a cell, wherein the polypeptide is formed as the translation
product of the polynucleotide, and whereby the deficiency or
absence of the polypeptide is compensated for. In preferred
embodiments, the preparation is introduced into muscle tissue and
the method is applied repetitively. The method is advantageously
applied where the deficiency or absence is due to a genetic defect.
The polynucleotide is preferably a non-replicating DNA sequence;
the DNA sequence may also be incorporated into a plasmid vector
which comprises an origin of replication.
[0043] In one of the preferred embodiments, the polynucleotide
codes for a non-secreted polypeptide, and the polypeptide remains
in situ. According to this embodiment, when the polynucleotide
codes for the polypeptide dystrophin, the method provides a therapy
for Duchenne's syndrome; alternatively, when the polynucleotide
codes for the polypeptide phenylalanine hydroxylase, the method
comprises a therapy for phenylketonuria. In another preferred
embodiment of the method, the polynucleotide codes for a
polypeptide which is secreted by the cell and released into the
circulation of the vertebrate; in a particularly preferred
embodiment the polynucleotide codes for human growth hormone.
[0044] In yet another embodiment of the method, there is provided a
therapy for hypercholesterolemia wherein a polynucleotide coding
for a receptor associated with cholesterol homeostasis is
introduced into a liver cell, and the receptor is expressed by the
cell.
[0045] In accordance with another aspect of the present invention,
there is provided a method for immunizing a vertebrate, comprising
the steps of obtaining a preparation comprising an expressible
polynucleotide coding for an immunogenic translation product, and
introducing the preparation into a vertebrate wherein the
translation product of the polynucleotide is formed by a cell of
the vertebrate, which elicits an immune response against the
immunogen. In one embodiment of the method, the injectable
preparation comprises a pharmaceutically acceptable carrier
containing an expressible polynucleotide coding for an immunogenic
peptide, and on the introduction of the preparation into the
vertebrate, the polynucleotide is incorporated into a cell of the
vertebrate wherein an immunogenic translation product of the
polynucleotide is formed, which elicits an immune response against
the immunogen.
[0046] In an alternative embodiment, the preparation comprises one
or more cells obtained from the vertebrate and transfected in vitro
with the polynucleotide, whereby the polynucleotide is incorporated
into said cells, where an immunogenic translation product of the
polynucleotide is formed, and whereby on the introduction of the
preparation into the vertebrate, an immune response against the
immunogen is elicited. In any of the embodiments of the invention,
the immunogenic product may be secreted by the cells, or it may be
presented by a cell of the vertebrate in the context of the major
histocompatibility antigens, thereby eliciting an immune response
against the immunogen. The method may be practiced using
non-dividing, differentiated cells from the vertebrates, which
cells may be lymphocytes, obtained from a blood sample;
alternatively, it may be practiced using partially differentiated
skin fibroblasts which are capable of dividing. In a preferred
embodiment, the method is practiced by incorporating the
polynucleotide coding for an immunogenic translation product into
muscle tissue.
[0047] The polynucleotide used for immunization is preferably an
mRNA sequence, although a non-replicating DNA sequence may be used.
The polynucleotide may be introduced into tissues of the body using
the injectable carrier alone; liposomal preparations are preferred
for methods in which in vitro transfections of cells obtained from
the vertebrate are carried out.
[0048] The carrier preferably is isotonic, hypotonic, or weakly
hypertonic, and has a relatively low ionic strength, such as
provided by a sucrose solution. The preparation may further
advantageously comprise a source of a cytokine which is
incorporated into liposomes in the form of a polypeptide or as a
polynucleotide.
[0049] The method may be used to selectively elicit a humoral
immune response, a cellular immune response, or a mixture of these.
In embodiments wherein the cell expresses major histocompatibility
complex of Class I, and the immunogenic peptide is presented in the
context of the Class I complex, the immune response is cellular and
comprises the production of cytotoxic T-cells.
[0050] In one such embodiment, the immunogenic peptide is
associated with a virus, is presented in the context of Class I
antigens, and stimulates cytotoxic T-cells which are capable of
destroying cells infected with the virus. A cytotoxic T-cell
response may also be produced according the method where the
polynucleotide codes for a truncated viral antigen lacking humoral
epitopes.
[0051] In another of these embodiments, the immunogenic peptide is
associated with a tumor, is presented in the context of Class I
antigens, and stimulates cytotoxic T cells which are capable of
destroying tumor cells. In yet another embodiment wherein the
injectable preparation comprises cells taken from the animal and
transfected in vitro, the cells expressing major histocompatibility
antigen of class I and class II, and the immune response is both
humoral and cellular and comprises the production of both antibody
and cytotoxic T-cells.
[0052] In another embodiment, there is provided a method of
immunizing a vertebrate, comprising the steps of obtaining a
positively charged liposome containing an expressible
polynucleotide coding for an immunogenic peptide, and introducing
the liposome into a vertebrate, whereby the liposome is
incorporated into a monocyte, a macrophage, or another cell, where
an immunogenic translation product of the polynucleotide is formed,
and the product is processed and presented by the cell in the
context of the major histocompatibility complex, thereby eliciting
an immune response against the immunogen. Again, the polynucleotide
is preferably mRNA, although DNA may also be used. And as before,
the method may be practiced without the liposome, utilizing just
the polynucleotide in an injectable carrier. The present invention
also encompasses the use of DNA coding for a polypeptide and for a
polymerase for transcribing the DNA, and wherein the DNA includes
recognition sites for the polymerase. The initial quantity of
polymerase is provided by including mRNA coding therefor in the
preparation, which mRNA is translated by the cell. The mRNA
preferably is provided with means for retarding its degradation in
the cell. This can include capping the mRNA, circularizing the
mRNA, or chemically blocking the 5' end of the mRNA. The DNA used
in the invention may be in the form of linear DNA or may be a
plasmid. Episomal DNA is also contemplated. One preferred
polymerase is phage T7 RNA polymerase and a preferred recognition
site is a T7 RNA polymerase promoter.
BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES
[0053] FIG. 1 comprises autoradiograms of chromatographic studies
showing the expression of the CAT gene in mouse muscle.
[0054] FIGS. 2A to 2F comprise photomicrographs of muscle tissue
stained for .beta.-galactosidase activity following injection with
the pRSVLac-Z DNA vector.
[0055] FIGS. 3A, 3B, and 3C present data for luciferase activity in
muscle following the injection of .beta.gLuc.beta.gA.sub.n into
muscle.
[0056] FIG. 4 presents an autoradiogram of a Southern blot after
analysis of extracts from pRSVL-injected muscle.
[0057] FIGS. 5A and 5B comprise graphs showing antibody production
in mice following the injection of a gene for an immunogenic
peptide.
[0058] FIGS. 6A and 6B comprise graphs showing antibody production
in mice following the injection of mouse cells transfected with a
gene for an immunogenic peptide.
DETAILED DESCRIPTION OF THE INVENTION
[0059] The practice of the present invention requires obtaining
naked polynucleotide operatively coding for a polypeptide for
incorporation into vertebrate cells. A polynucleotide operatively
codes for a polypeptide when it has all the genetic information
necessary for expression by a target cell, such as promoters and
the like. These polynucleotides can be administered to the
vertebrate by any method that delivers injectable materials to
cells of the vertebrate, such as by injection into the interstitial
space of tissues such as muscles or skin, introduction into the
circulation or into body cavities or by inhalation or insufflation.
A naked polynucleotide is injected or otherwise delivered to the
animal with a pharmaceutically acceptable liquid carrier. In
preferred applications, the liquid carrier is aqueous or partly
aqueous, comprising sterile, pyrogen-free water. The pH of the
preparation is suitably adjusted and buffered. The polynucleotide
can comprise a complete gene, a fragment of a gene, or several
genes, together with recognition and other sequences necessary for
expression.
[0060] In the embodiments of the invention that require use of
liposomes, for example, when the polynucleotide is to be associated
with a liposome, it requires a material for forming liposomes,
preferably cationic or positively charged liposomes, and requires
that liposomal preparations be made from these materials. With the
liposomal material in hand, the polynucleotide may advantageously
be used to transfect cells in vitro for use as immunizing agents,
or to administer polynucleotides into bodily sites where liposomes
may be taken up by phagocytic cells.
[0061] Polynucleotide Materials
[0062] The naked polynucleotide materials used according to the
methods of the invention comprise DNA and RNA sequences or DNA and
RNA sequences coding for polypeptides that have useful therapeutic
applications. These polynucleotide sequences are naked in the sense
that they are free from any delivery vehicle that can act to
facilitate entry into the cell, for example, the polynucleotide
sequences are free of viral sequences, particularly any viral
particles which may carry genetic information. They are similarly
free from, or naked with respect to, any material which promotes
transfection, such as liposomal formulations, charged lipids such
as Lipofectin.TM. or precipitating agents such as CaPO.sub.4.
[0063] The DNA sequences used in these methods can be those
sequences which do not integrate into the genome of the host cell.
These may be non-replicating DNA sequences, or specific replicating
sequences genetically engineered to lack the genome-integration
ability.
[0064] The polynucleotide sequences of the invention are DNA or RNA
sequences having a therapeutic effect after being taken up by a
cell. Examples of polynucleotides that are themselves therapeutic
are anti-sense DNA and RNA; DNA coding for an anti-sense RNA; or
DNA coding for tRNA or rRNA to replace defective or deficient
endogenous molecules. The polynucleotides of the invention can also
code for therapeutic polypeptides. A polypeptide is understood to
be any translation product of a polynucleotide regardless of size,
and whether glycosylated or not. Therapeutic polypeptides include
as a primary example, those polypeptides that can compensate for
defective or deficient species in an animal, or those that act
through toxic effects to limit or remove harmful cells from the
body.
[0065] Therapeutic polynucleotides provided by the invention can
also code for immunity-conferring polypeptides, which can act as
endogenous immunogens to provoke a humoral or cellular response, or
both. The polynucleotides employed according to the present
invention can also code for an antibody. In this regard, the term
"antibody" encompasses whole immunoglobulin of any class, chimeric
antibodies and hybrid antibodies with dual or multiple antigen or
epitope specificities, and fragments, such as F(ab).sub.2, Fab',
Fab and the like, including hybrid fragments. Also included within
the meaning of "antibody" are conjugates of such fragments, and
so-called antigen binding proteins (single chain antibodies) as
described, for example, in U.S. Pat. No. 4,704,692, the contents of
which are hereby incorporated by reference.
[0066] Thus, an isolated polynucleotide coding for variable regions
of an antibody can be introduced, in accordance with the present
invention, to enable the treated subject to produce antibody in
situ. For illustrative methodology relating to obtaining
antibody-encoding polynucleotides, see Ward et al. Nature,
341:544-546 (1989); Gillies et al., Biotechnol. 7:799-804 (1989);
and Nakatani et al., loc. cit., 805-810 (1989). The antibody in
turn would exert a therapeutic effect, for example, by binding a
surface antigen associated with a pathogen. Alternatively, the
encoded antibodies can be anti-idiotypic antibodies (antibodies
that bind other antibodies) as described, for example, in U.S. Pat.
No. 4,699,880. Such anti-idiotypic antibodies could bind endogenous
or foreign antibodies in a treated individual, thereby to
ameliorate or prevent pathological conditions associated with an
immune response, e.g., in the context of an autoimmune disease.
[0067] Polynucleotide sequences of the invention preferably code
for therapeutic or immunogenic polypeptides, and these sequences
may be used in association with other polynucleotide sequences
coding for regulatory proteins that control the expression of these
polypeptides. The regulatory protein can act by binding to genomic
DNA so as to regulate its transcription;
[0068] alternatively, it can act by binding to messenger RNA to
increase or decrease its stability or translation efficiency.
[0069] The polynucleotide material delivered to the cells in vivo
can take any number of forms, and the present invention is not
limited to any particular polynucleotide coding for any particular
polypeptide. Plasmids containing genes coding for a large number of
physiologically active peptides and antigens or immunogens have
been reported in the literature and can be readily obtained by
those of skill in the art.
[0070] Where the polynucleotide is to be DNA, promoters suitable
for use in various vertebrate systems are well known. For example,
for use in murine systems, suitable strong promoters include RSV
LTR, MPSV LTR, SV40 IEP, and metallothionein promoter. In humans,
on the other hand, promoters such as CMV IEP may advantageously be
used. All forms of DNA, whether replicating or non-replicating,
which do not become integrated into the genome, and which are
expressible, are within the methods contemplated by the
invention.
[0071] With the availability of automated nucleic acid synthesis
equipment, both DNA and RNA can be synthesized directly when the
nucleotide sequence is known or by a combination of PCR cloning and
fermentation. Moreover, when the sequence of the desired
polypeptide is known, a suitable coding sequence for the
polynucleotide can be inferred.
[0072] When the polynucleotide is mRNA, it can be readily prepared
from the corresponding DNA in vitro. For example, conventional
techniques utilize phage RNA polymerases SP6, T3, or T7 to prepare
mRNA from DNA templates in the presence of the individual
ribonucleoside triphosphates. An appropriate phage promoter, such
as a T7 origin of replication site is placed in the template DNA
immediately upstream of the gene to be transcribed. Systems
utilizing T7 in this manner are well known, and are described in
the literature, e.g., in Current Protocols in Molecular Biology,
.sctn.3.8 (Vol. 1 1988).
[0073] One particularly preferred method for obtaining the mRNA
used in the present invention is set forth in Examples 2-5. In
general, however, it should be apparent that the pXGB plasmid or
any similar plasmid that can be readily constructed by those of
ordinary skill in the art can be used with a virtually unlimited
number of cDNAs in practicing the present invention. Such plasmids
may advantageously comprise a promoter for a desired RNA
polymerase, followed by a 5' untranslated region, a 3' untranslated
region, and a template for a poly A tract. There should be a unique
restriction site between these 5' and 3' regions to facilitate the
insertion of any desired cDNA into the plasmid. Then, after cloning
the plasmid containing the desired gene, the plasmid is linearized
by cutting in the polyadenylation region and is transcribed in
vitro to form mRNA transcripts. These transcripts are preferably
provided with a 5' cap, as demonstrated in Example 5.
[0074] Alternatively, a 5' untranslated sequence such as EMC can be
used which does not require a 5' cap.
[0075] While the foregoing represents a preferred method for
preparing the mRNA, it will be apparent to those of skill in the
art that many alternative methods also exist. For example, the mRNA
can be prepared in commercially-available nucleotide synthesis
apparatus. Alternatively, mRNA in circular form can be prepared.
Exonuclease-resistant RNAs such as circular mRNA, chemically
blocked mRNA, and mRNA with a 5' cap are preferred, because of
their greater half-life in vivo.
[0076] In particular, one preferred mRNA is a self-circularizing
mRNA having the gene of interest preceded by the 5' untranslated
region of polio virus. It has been demonstrated that circular mRNA
has an extremely long half-life (Harland & Misher, Development
102: 837-852 (1988)) and that the polio virus 5' untranslated
region can promote translation of mRNA without the usual 5' cap
(Pelletier & Sonnenberg, Nature 334:320-325 (1988), hereby
incorporated by reference).
[0077] This material may be prepared from a DNA template that is
self-splicing and generates circular "lariat" mRNAs, using the
method of Been & Cech, Cell 47:206-216 (1986)(hereby
incorporated by reference). We modify that template by including
the 5' untranslated region of the polio virus immediately upstream
of the gene of interest, following the procedure of Maniatis, T. et
al. Molecular Cloning: A Laboratory Manual, Cold Spring Harbor,
N.Y. (1982).
[0078] In addition, the present invention includes the use of mRNA
that is chemically blocked at the 5' and/or 3' end to prevent
access by RNAse. (This enzyme is an exonuclease and therefore does
not cleave RNA in the middle of the chain.) Such chemical blockage
can substantially lengthen the half life of the RNA in vivo. Two
agents which may be used to modify RNA are available from Clonetech
Laboratories, Inc., Palo Alto, Calif.: C2 AminoModifier (Catalog #
5204-1) and Amino-7-dUTP (Catalog # K1022-1). These materials add
reactive groups to the RNA. After introduction of either of these
agents onto an RNA molecule of interest, an appropriate reactive
substituent can be linked to the RNA according to the
manufacturer's instructions. By adding a group with sufficient
bulk, access to the chemically modified RNA by RNAse can be
prevented.
[0079] Transient Gene Therapy
[0080] Unlike gene therapies proposed in the past, one major
advantage of the present invention is the transitory nature of the
polynucleotide synthesis in the cells. (We refer to this as
reversible gene therapy, transient gene therapy or TGT.) With mRNA
introduced according to the present invention, the effect will
generally last about one day. Also, in marked contrast to gene
therapies proposed in the past, mRNA does not have to penetrate the
nucleus to direct protein synthesis; therefore, it should have no
genetic liability.
[0081] In some situations, however, a more prolonged effect may be
desired without incorporation of the exogenous polynucleic acid
into the genome of the host organism.
[0082] In order to provide such an effect, a preferred embodiment
of the invention provides introducing a DNA sequence coding for a
specific polypeptide into the cell. We have found, according to the
methods of the invention, that non-replicating DNA sequences can be
introduced into cells to provide production of the desired
polypeptide for periods of about up to six months, and we have
observed no evidence of integration of the DNA sequences into the
genome of the cells. Alternatively, an even more prolonged effect
can be achieved by introducing the DNA sequence into the cell by
means of a vector plasmid having the DNA sequence inserted
therein.
[0083] Preferably, the plasmid further comprises a replicator. Such
plasmids are well known to those skilled in the art, for example,
plasmid pBR322, with replicator pMB1, or plasmid pMK16, with
replicator ColE1 (Ausubel, Current Protocols in Molecular Biology,
John Wiley and Sons, New York (1988) .sctn.II:1.5.2.
[0084] Results of studies of the time course of expression of DNA
and mRNA introduced into muscle cells as described in Examples 1
and 13 indicate that mRNA expression is more rapid, although
shorter in duration than DNA expression. An immediate and long
lived gene expression can be achieved by administering to the cell
a liposomal preparation comprising both DNA and an RNA polymerase,
such as the phage polymerases T7, T3, and SP6. The liposome also
includes an initial source of the appropriate RNA polymerase, by
either including the actual enzyme itself, or alternatively, an
mRNA coding for that enzyme. When the liposome is introduced into
the organism, it delivers the DNA and the initial source of RNA
polymerase to the cell. The RNA polymerase, recognizing the
promoters on the introduced DNA, transcribes both genes, resulting
in translation products comprising more RNA polymerase and the
desired polypeptide. Production of these materials continues until
the introduced DNA (which is usually in the form of a plasmid) is
degraded. In this manner, production of the desired polypeptide in
vivo can be achieved in a few hours and be extended for one month
or more.
[0085] Although not limited to the treatment of genetic disease,
the methods of the invention can accordingly be appropriately
applied to treatment strategies requiring delivery and functional
expression of missing or defective genes.
[0086] The polynucleotides may be delivered to the interstitial
space of tissues of the animal body, including those of muscle,
skin, brain, lung, liver, spleen, bone marrow, thymus, heart,
lymph, blood, bone, cartilage, pancreas, kidney, gall bladder,
stomach, intestine, testis, ovary, uterus, rectum, nervous system,
eye, gland, and connective tissue. Interstitial space of the
tissues comprises the intercellular, fluid, mucopolysaccharide
matrix among the reticular fibers of organ tissues, elastic fibers
in the walls of vessels or chambers, collagen fibers of fibrous
tissues, or that same matrix within connective tissue ensheathing
muscle cells or in the lacunae of bone. It is similarly the space
occupied by the plasma of the circulation and the lymph fluid of
the lymphatic channels.
[0087] Delivery to the interstitial space of muscle tissue is
preferred for the reasons discussed below. They may be conveniently
delivered by injection into the tissues comprising these cells.
They are preferably delivered to and expressed in persistent,
non-dividing cells which are differentiated, although delivery and
expression may be achieved in non-differentiated or less completely
differentiated cells, such as, for example, stem cells of blood or
skin fibroblasts. We have discovered that in vivo muscle cells are
particularly competent in their ability to take up and express
polynucleotides. This ability may be due to the singular tissue
architecture of muscle, comprising multinucleated cells,
sarcoplasmic reticulum, and transverse tubular system.
Polynucleotides may enter the muscle through the transverse tubular
system, which contains extracellular fluid and extends deep into
the muscle cell. It is also possible that the polynucleotides enter
damaged muscle cells which then recover.
[0088] Muscle is also advantageously used as a site for the
delivery and expression of polynucleotides in a number of
therapeutic applications because animals have a proportionately
large muscle mass which is conveniently accessed by direct
injection through the skin; for this reason, a comparatively large
dose of polynucleotides can be deposited in muscle by multiple
injections, and repetitive injections, to extend therapy over long
periods of time, are easily performed and can be carried out safely
and without special skill or devices.
[0089] Muscle tissue can be used as a site for injection and
expression of polynucleotides in a set of general strategies, which
are exemplary and not exhaustive. First, muscle disorders related
to defective or absent gene products can be treated by introducing
polynucleotides coding for a non-secreted gene product into the
diseased muscle tissue. In a second strategy, disorders of other
organs or tissues due to the absence of a gene product, and which
results in the build-up of a circulating toxic metabolite can be
treated by introducing the specific therapeutic polypeptide into
muscle tissue where the non-secreted gene product is expressed and
clears the circulating metabolite. In a third strategy, a
polynucleotide coding for an secretable therapeutic polypeptide can
be injected into muscle tissue from where the polypeptide is
released into the circulation to seek a metabolic target. This use
is demonstrated in the expression of growth hormone gene injected
into muscle, Example 18. Certain DNA segments, are known to serve
as "signals" to direct secretion (Wickner, W. T. and H. F. Lodish,
Science 230:400-407 (1985), and these may be advantageously
employed. Finally, in immunization strategies, muscle cells may be
injected with polynucleotides coding for immunogenic peptides, and
these peptides will be presented by muscle cells in the context of
antigens of the major histocompatibility complex to provoke a
selected immune response against the immunogen.
[0090] Tissues other than those of muscle, and having a less
efficient uptake and expression of injected polynucleotides, may
nonetheless be advantageously used as injection sites to produce
therapeutic polypeptides or polynucleotides under certain
conditions. One such condition is the use of a polynucleotide to
provide a polypeptide which to be effective must be present in
association with cells of a specific type; for example, the cell
surface receptors of liver cells associated with cholesterol
homeostasis. (Brown and Goldstein, Science 232:34-47 (1986)). In
this application, and in many others, such as those in which an
enzyme or hormone is the gene product, it is not necessary to
achieve high levels of expression in order to effect a valuable
therapeutic result.
[0091] One application of TGT is in the treatment of muscular
dystrophy. The genetic basis of the muscular dystrophies is just
beginning to be unraveled. The gene related to Duchenne/Becker
muscular dystrophy has recently been cloned and encodes a rather
large protein, termed dystrophin. Retroviral vectors are unlikely
to be useful, because they could not accommodate the rather large
size of the cDNA (about 13 kb) for dystrophin. Very recently
reported work is centered on transplanting myoblasts, but the
utility of this approach remains to be determined. Clearly, an
attractive approach would be to directly express the dystrophin
gene within the muscle of patients with Duchennes. Since most
patients die from respiratory failure, the muscles involved with
respiration would be a primary target.
[0092] Another application is in the treatment of cystic fibrosis.
The gene for cystic fibrosis was recently identified (Goodfellow,
P. Nature, 341(6238):102-3 (Sep. 14, 1989); Rommens, J. et al.
Science, 245(4922):1059-1065 (Sep. 8, 1989); Beardsley, T. et al.,
Scientific American, 261(5):28-30 (1989). Significant amelioration
of the symptoms should be attainable by the expression of the
dysfunctional protein within the appropriate lung cells. The
bronchial epithelial cells are postulated to be appropriate target
lung cells and they could be accessible to gene transfer following
instillation of genes into the lung. Since cystic fibrosis is an
autosomal recessive disorder one would need to achieve only about
5% of normal levels of the cystic fibrosis gene product in order to
significantly ameliorate the pulmonary symptoms.
[0093] Biochemical genetic defects of intermediary metabolism can
also be treated by TGT. These diseases include phenylketonuria,
galactosemia, maple-syrup urine disease, homocystinuria, propionic
acidemia, methylmalonic acidemia, and adenosine deaminase
deficiency. The pathogenesis of disease in most of these disorders
fits the phenylketonuria (PKU) model of a circulating toxic
metabolite. That is, because of an enzyme block, a biochemical,
toxic to the body, accumulates in body fluids. These disorders are
ideal for gene therapy for a number of reasons. First, only 5% of
normal levels of enzyme activity would have to be attained in order
to significantly clear enough of the circulating toxic metabolite
so that the patient is significantly improved. Second, the
transferred gene could most often be expressed in a variety of
tissues and still be able to clear the toxic biochemical.
[0094] Reversible gene therapy can also be used in treatment
strategies requiring intracytoplasmic or intranuclear protein
expression. Some proteins are known that are capable of regulating
transcription by binding to specific promoter regions on nuclear
DNA. Other proteins bind to RNA, regulating its degradation,
transport from the nucleus, or translation efficiency. Proteins of
this class must be delivered intracellularly for activity.
Extracellular delivery of recombinant transcriptional or
translational regulatory proteins would not be expected to have
biological activity, but functional delivery of the DNA or RNA by
TGT would be active. Representative proteins of this type that
would benefit from TGT would include NEF, TAT, steroid receptor and
the retinoid receptor.
[0095] Gene therapy can be used in a strategy to increase the
resistance of an AIDS patient to HIV infection. Introducing an AIDS
resistance gene, such as, for example, the NEF gene or the soluble
CD4 gene to prevent budding, into an AIDS patient's T cells will
render his T cells less capable of producing active AIDS virus,
thus sparing the cells of the immune system and improving his
ability to mount a T cell dependent immune response. Thus, in
accordance with the invention, a population of the AIDS patient's
own T cells is isolated from the patient's blood. These cells are
then transfected in vitro and then reintroduced back into the
patient's blood. The virus-resistant cells will have a selective
advantage over the normal cells, and eventually repopulate the
patient's lymphatic system. DNA systemic delivery to macrophages or
other target cells can be used in addition to the extracorporeal
treatment strategy. Although this strategy would not be expected to
eradicate virus in the macrophage reservoir, it will increase the
level of T cells and improve the patient's immune response.
[0096] In all of the systemic strategies presented herein, an
effective DNA or mRNA dosage will generally be in the range of from
about 0.05 .mu.g/kg to about 50 mg/kg, usually about 0.005-5 mg/kg.
However, as will be appreciated, this dosage will vary in a manner
apparent to those of skill in the art according to the activity of
the peptide coded for by the DNA or mRNA and the particular peptide
used. For delivery of adenosine deaminase to mice or humans, for
example, adequate levels of translation are achieved with a DNA or
mRNA dosage of about 0.5 to 5 mg/kg. See Example 10. From this
information, dosages for other peptides of known activity can be
readily determined.
[0097] Diseases which result from deficiencies of critical proteins
may be appropriately treated by introducing into specialized cells,
DNA or mRNA coding for these proteins. A variety of growth factors
such as nerve growth factor and fibroblast growth factor have been
shown to affect neuronal cell survival in animal models of
Alzheimer's disease. In the aged rat model, NGF infusions have
reversed the loss of cholinergic neurons. In the fimbria-fomix
lesion rat, NGF infusions or secretion from genetically-modified
fibroblasts have also avoided the loss of cholinergic function.
Cholinergic activity is diminished in patients with Alzheimer's.
The expression within the brain of transduced genes expressing
growth factors could reverse the loss of function of specific
neuronal groups.
[0098] Introduction of DNA or mRNA by transfection of the gene for
neuronal growth factor into cells lining the cranial cavity can be
used in accordance with the present invention in the treatment of
Alzheimer's disease.
[0099] In particular, the present invention treats this disease by
intracranial injection of from about 10 .mu.g to about 100 .mu.g of
DNA or mRNA into the parenchyma through use of a stereotaxic
apparatus. Specifically, the injection is targeted to the
cholinergic neurons in the medial septum. The DNA or mRNA injection
is repeated every 1-3 days for 5' capped, 3' polyadenylated mRNA,
and every week to 21 days for circular mRNA, and every 30 to 60
days for DNA.
[0100] Injection of DNA in accordance with the present invention is
also contemplated. DNA would be injected in corresponding amounts;
however, frequency of injection would be greatly reduced. Episomal
DNA, for example, could be active for a number of months, and
reinjection would only be necessary upon notable regression by the
patient.
[0101] In addition, the enzymes responsible for neurotransmitter
synthesis could be expressed from transduced genes. For example,
the gene for choline acetyl transferase could be expressed within
the brain cells (neurons or glial) of specific areas to increase
acetylcholine levels and improve brain function.
[0102] The critical enzymes involved in the synthesis of other
neurotransmitters such as dopamine, norepinephrine, and GABA have
been cloned and available. The critical enzymes could be locally
increased by gene transfer into a localized area of the brain. The
increased productions of these and other neurotransmitters would
have broad relevance to manipulation of localized neurotransmitter
function and thus to a broad range of brain disease in which
disturbed neurotransmitter function plays a crucial role.
Specifically, these diseases could include schizophrenia and
manic-depressive illnesses and Parkinson's Disease. It is well
established that patients with Parkinson's suffer from
progressively disabled motor control due to the lack of dopamine
synthesis within the basal ganglia. The rate limiting step for
dopamine synthesis is the conversion of tyrosine to L-DOPA by the
enzyme, tyrosine hydroxylase. L-DOPA is then converted to dopamine
by the ubiquitous enzyme, DOPA decarboxylase. That is why the
well-established therapy with L-DOPA is effective (at least for the
first few years of treatment). Gene therapy could accomplish the
similar pharmacologic objective by expressing the genes for
tyrosine hydroxylase and possibly DOPA decarboxylase as well.
Tyrosine is readily available within the CNS.
[0103] The genetic form of alpha-1-antitrypsin deficiency can
result in both liver and lung disease. The liver disease, which is
less common, is caused by the accumulation of an abnormal protein
and would be less amenable to gene therapy. The pulmonary
complications, however, would be amenable to the increased
expression of alpha-1-antitrypsin within the lung. This should
prevent the disabling and eventually lethal emphysema from
developing.
[0104] Alpha-1-antitrypsin deficiency also occurs in tobacco
smokers since tobacco smoke decreases alpha-1-antitrypsin activity
and thus serine protease activity that leads to emphysema. In
addition, some recent data links tobacco smoke's anti-trypsin
effect to aneurysms of the aorta. Aneurysms would also be
preventable by raising blood levels of anti-1-antitrypsin since
this would decrease protease activity that leads to aneurysms.
[0105] Patients with degenerative disease of the lung could also
benefit from the expression of enzymes capable of removing other
toxic metabolites which tend to accumulate in diseased lung tissue.
Superoxide dismutase and catalase could be delivered by TGT to
ameliorate these problems.
[0106] TGT can be used in treatment strategies requiring the
delivery of cell surface receptors. It could be argued that there
is no need to decipher methodology for functional in vivo delivery
of genes. There is, after all, an established technology for the
synthesis and large scale production of proteins, and proteins are
the end product of gene expression. This logic applies for many
protein molecules which act extracellularly or interact with cell
surface receptors, such as tissue plasminogen activator (TPA),
growth hormone, insulin, interferon, granulocyte-macrophage colony
stimulating factor (GMCSF), erythropoietin (EPO), etc. However, the
drug delivery problems associated with properly delivering a
recombinant cell surface receptor to be inserted in the plasma
membrane of its target cell in the proper orientation for a
functional receptor have hithertofore appeared intractable. When
DNA or RNA coding for a cell surface receptor is delivered
intracellularly in accordance with the present invention, the
resulting protein can be efficiently and functionally expressed on
the target cell surface. If the problem of functional delivery of
recombinant cell surface receptors remains intractable, then the
only way of approaching this therapeutic modality will be through
gene delivery. Similar logic for nuclear or cytoplasmic regulation
of gene expression applies to nuclear regulatory factor bound to
DNA to regulate (up or down) RNA transcription and to cytoplasmic
regulatory factors which bind to RNA to increase or decrease
translational efficiency and degradation. TGT could in this way
provide therapeutic strategies for the treatment of cystic
fibrosis, muscular dystrophy and hypercholesterolemia.
[0107] Elevated levels of cholesterol in the blood may be reduced
in accordance with the present invention by supplying mRNA coding
for the LDL surface receptor to hepatocytes. A slight elevation in
the production of this receptor in the liver of patients with
elevated LDL will have significant therapeutic benefits. Therapies
based on systemic administration of recombinant proteins are not
able to compete with the present invention, because simply
administering the recombinant protein could not get the receptor
into the plasma membrane of the target cells. The receptor must be
properly inserted into the membrane in order to exert its
biological effect. It is not usually necessary to regulate the
level of receptor expression; the more expression the better. This
simplifies the molecular biology involved in preparation of the
mRNA for use in the present invention. For example, lipid/DNA or
RNA complexes containing the LDL receptor gene may be prepared and
supplied to the patient by repetitive I.V. injections. The lipid
complexes will be taken up largely by the liver. Some of the
complexes will be taken up by hepatocytes. The level of LDL
receptor in the liver will increase gradually as the number of
injections increases. Higher liver LDL receptor levels will lead to
therapeutic lowering of LDL and cholesterol. An effective mRNA dose
will generally be from about 0.1 to about 5 mg/kg.
[0108] Other examples of beneficial applications of TGT include the
introduction of the thymidine kinase gene into macrophages of
patients infected with the HIV virus. Introduction of the thymidine
kinase gene into the macrophage reservoir will render those cells
more capable of phosphorylating AZT. This tends to overcome their
resistance to AZT therapy, making AZT capable of eradicating the
HIV reservoir in macrophages. Lipid/DNA complexes containing the
thymidine kinase gene can be prepared and administered to the
patient through repetitive intravenous injections. The lipid
complexes will be taken up largely by the macrophage reservoir
leading to elevated levels of thymidine kinase in the macrophages.
This will render the AZT resistant cells subject to treatment with
AZT. The thymidine kinase therapy can also be focused by putting
the thymidine kinase gene under the control of the HTLV III
promoter. According to this strategy, the thymidine kinase would
only be synthesized on infection of the cell by HIV virus, and the
production of the Tat protein which activates the promoter. An
analogous therapy would supply cells with the gene for diphtheria
toxin under the control of the same HTLV III promoter, with the
lethal result occurring in cells only after HIV infection.
[0109] These AIDS patients could also be treated by supplying the
interferon gene to the macrophages according to the TGT method.
Increased levels of localized interferon production in macrophages
could render them more resistant to the consequences of HIV
infection. While local levels of interferon would be high, the
overall systemic levels would remain low, thereby avoiding the
systemic toxic effects like those observed after recombinant
interferon administration. Lipid/DNA or RNA complexes containing
the interferon gene can be prepared and administered to the patient
by repetitive intravenous injections. The lipid complexes will be
taken up largely by the macrophage reservoir leading to elevated
localized levels of interferon in the macrophages. This will render
them less susceptible to HIV infection.
[0110] Various cancers may be treated using TGT by supplying a
diphtheria toxin gene on a DNA template with a tissue specific
enhancer to focus expression of the gene in the cancer cells.
Intracellular expression of diphtheria toxin kills cells. These
promoters could be tissue-specific such as using a
pancreas-specific promoter for the pancreatic cancer. A functional
diphtheria toxin gene delivered to pancreatic cells could eradicate
the entire pancreas. This strategy could be used as a treatment for
pancreatic cancer. The patients would have no insurmountable
difficulty surviving without a pancreas. The tissue specific
enhancer would ensure that expression of diphtheria toxin would
only occur in pancreatic cells. DNA/lipid complexes containing the
diphtheria toxin gene under the control of a tissue specific
enhancer would be introduced directly into a cannulated artery
feeding the pancreas. The infusion would occur on some dosing
schedule for as long as necessary to eradicate the pancreatic
tissue. Other lethal genes besides diphtheria toxin could be used
with similar effect, such as genes for ricin or cobra venom factor
or enterotoxin.
[0111] Also, one could treat cancer by using a cell-cycle specific
promoter that would only kill cells that are rapidly cycling
(dividing) such as cancer cells. Cell-cycle specific killing could
also be accomplished by designing mRNA encoding killer proteins
that are stable only in cycling cells (i.e. histone mRNA that is
only stable during S phase). Also, one could use
developmental-specific promoters such as the use of
alpha-fetoprotein that is only expressed in fetal liver cells and
in hepatoblastoma cells that have dedifferentiated into a more
fetal state.
[0112] One could also treat specialized cancers by the transfer of
genes such as the retinoblastoma gene (and others of that family)
that suppress the cancer properties of certain cancers.
[0113] The TGT strategy can be used to provide a controlled,
sustained delivery of peptides. Conventional drugs, as well as
recombinant protein drugs, can benefit from controlled release
devices. The purpose of the controlled release device is to deliver
drugs over a longer time period, so that the number of doses
required is reduced. This results in improvements in patient
convenience and compliance. There are a wide variety of emerging
technologies that are intended to achieve controlled release.
[0114] TGT can be used to obtain controlled delivery of therapeutic
peptides. Regulated expression can be obtained by using suitable
promoters, including cell-specific promoters. Suitable peptides
delivered by the present invention include, for example, growth
hormone, insulin, interleukins, interferons, GMCSF, EPO, and the
like. Depending on the specific application, the DNA or an RNA
construct selected can be designed to result in a gene product that
is secreted from the injected cells and into the systemic
circulation.
[0115] TGT can also comprise the controlled delivery of therapeutic
polypeptides or peptides which is achieved by including with the
polynucleotide to be expressed in the cell, an additional
polynucleotide which codes for a regulatory protein which controls
processes of transcription and translation. These polynucleotides
comprise those which operate either to up regulate or down regulate
polypeptide expression, and exert their effects either within the
nucleus or by controlling protein translation events in the
cytoplasm.
[0116] The T7 polymerase gene can be used in conjunction with a
gene of interest to obtain longer duration of effect of TGT.
Episomal DNA such as that obtained from the origin of replication
region for the Epstein Barr virus can be used, as well as that from
other origins of replication which are functionally active in
mammalian cells, and preferably those that are active in human
cells. This is a way to obtain expression from cells after many
cell divisions, without risking unfavorable integration events that
are common to retrovirus vectors. Controlled release of calcitonin
could be obtained if a calcitonin gene under the control of its own
promoter could be functionally introduced into some site, such as
liver or skin. Cancer patients with hypercalcemia would be a group
to whom this therapy could be applied.
[0117] Other gene therapies using TGT can include the use of a
polynucleotide that has a therapeutic effect without being
translated into a polypeptide. For example, TGT can be used in the
delivery of anti-sense polynucleotides for turning off the
expression of specific genes. Conventional anti-sense methodology
suffers from poor efficacy, in part, because the oligonucleotide
sequences delivered are too short. With TGT, however, full length
anti-sense sequences can be delivered as easily as short oligomers.
Anti-sense polynucleotides can be DNA or RNA molecules that
themselves hybridize to (and, thereby, prevent transcription or
translation of) an endogenous nucleotide sequence.
[0118] Alternatively, an anti-sense DNA may encode an RNA that
hybridizes to an endogenous sequence, interfering with translation.
Other uses of TGT in this vein include delivering a polynucleotide
that encodes a tRNA or rRNA to replace a defective or deficient
endogenous tRNA or rRNA, the presence of which causes the
pathological condition.
[0119] Cell-specific promoters can also be used to permit
expression of the gene only in the target cell. For example,
certain genes are highly promoted in adults only in particular
types of tumors. Similarly, tissue-specific promoters for
specialized tissue, e.g., lens tissue of the eye, have also been
identified and used in heterologous expression systems.
[0120] Beyond the therapies described, the method of the invention
can be used to deliver polynucleotides to animal stock to increase
production of milk in dairy cattle or muscle mass in animals that
are raised for meat.
[0121] DNA and mRNA Vaccines
[0122] According to the methods of the invention, both expressible
DNA and mRNA can be delivered to cells to form therein a
polypeptide translation product. If the nucleic acids contain the
proper control sequences, they will direct the synthesis of
relatively large amounts of the encoded protein. When the DNA and
mRNA delivered to the cells codes for an immunizing peptide, the
methods can be applied to achieve improved and more effective
immunity against infectious agents, including intracellular
viruses, and also against tumor cells.
[0123] Since the immune systems of all vertebrates operate
similarly, the applications described can be implemented in all
vertebrate systems, comprising mammalian and avian species, as well
as fish.
[0124] The methods of the invention may be applied by direct
injection of the polynucleotide into cells of the animal in vivo,
or by in vitro transfection of some of the animal cells which are
then re-introduced into the animal body.
[0125] The polynucleotides may be delivered to various cells of the
animal body, including muscle, skin, brain, lung, liver, spleen, or
to the cells of the blood. Delivery of the polynucleotides directly
in vivo is preferably to the cells of muscle or skin. The
polynucleotides may be injected into muscle or skin using an
injection syringe. They may also be delivered into muscle or skin
using a vaccine gun.
[0126] It has recently been shown that cationic lipids can be used
to facilitate the transfection of cells in certain applications,
particularly in vitro transfection. Cationic lipid based
transfection technology is preferred over other methods; it is more
efficient and convenient than calcium phosphate, DEAE dextran or
electroporation methods, and retrovirus mediated transfection, as
discussed previously, can lead to integration events in the host
cell genome that result in oncogene activation or other undesirable
consequences. The knowledge that cationic lipid technology works
with messenger RNA is a further advantage to this approach because
RNA is turned over rapidly by intracellular nucleases and is not
integrated into the host genome. A transfection system that results
in high levels of reversible expression is preferred to alternative
methodology requiring selection and expansion of stably transformed
clones because many of the desired primary target cells do not
rapidly divide in culture.
[0127] The ability to transfect cells at high efficiency with
cationic liposomes provides an alternative method for immunization.
The gene for an antigen is introduced in to cells which have been
removed from an animal. The transfected cells, now expressing the
antigen, are reinjected into the animal where the immune system can
respond to the (now) endogenous antigen. The process can possibly
be enhanced by coinjection of either an adjuvant or lymphokines to
further stimulate the lymphoid cells.
[0128] Vaccination with nucleic acids containing a gene for an
antigen may also provide a way to specifically target the cellular
immune response. Cells expressing proteins which are secreted will
enter the normal antigen processing pathways and produce both a
humoral and cytotoxic response. The response to proteins which are
not secreted is more selective. Non-secreted proteins synthesized
in cells expressing only class I MHC molecules are expected to
produce only a cytotoxic vaccination. Expression of the same
antigen in cells bearing both class I and class II molecules may
produce a more vigorous response by stimulating both cytotoxic and
helper T cells. Enhancement of the immune response may also be
possible by injecting the gene for the antigen along with a peptide
fragment of the antigen. The antigen is presented via class I MHC
molecules to the cellular immune system while the peptide is
presented via class II MHC molecules to stimulate helper T cells.
In any case, this method provides a way to stimulate and modulate
the immune response in a way which has not previously been
possible.
[0129] A major disadvantage of subunit vaccines is that
glycoprotein antigens are seldom modified correctly in the
recombinant expression systems used to make the antigens.
Introducing the gene for a glycoprotein antigen will insure that
the protein product is synthesized, modified and processed in the
same species and cells that the pathogen protein would be. Thus,
the expression of a gene for a human viral glycoprotein will
contain the correct complement of sugar residues. This is important
because it has been demonstrated that a substantial component of
the neutralizing antibodies in some viral systems are directed at
carbohydrate epitopes.
[0130] Any appropriate antigen which is a candidate for an immune
response, whether humoral or cellular, can be used in its nucleic
acid form. The source of the cells could be fibroblasts taken from
an individual which provide a convenient source of cells expressing
only class I MHC molecules. Alternatively, peripheral blood cells
can be rapidly isolated from whole blood to provide a source of
cells containing both class I and class II MHC proteins. They could
be further fractionated into B cells, helper T cells, cytotoxic T
cells or macrophage/monocyte cells if desired. Bone marrow cells
can provide a source of less differentiated lymphoid cells. In all
cases the cell will be transfected either with DNA containing a
gene for the antigen or by the appropriate capped and
polyadenylated mRNA transcribed from that gene or a circular RNA,
chemically modified RNA, or an RNA which does not require 5'
capping. The choice of the transfecting nucleotide may depend on
the duration of expression desired. For vaccination purposes, a
reversible expression of the immunogenic peptide, as occurs on mRNA
transfection, is preferred. Transfected cells are injected into the
animal and the expressed proteins will be processed and presented
to the immune system by the normal cellular pathways.
[0131] Such an approach has been used to produce cytotoxic immunity
in model systems in mice. Cell lines, malignant continuously
growing cells, can be stably transformed with DNA. When cells are
injected into animals, they induce cellular immunity to the
expressed antigen. The cationic lipid delivery system will allow
this approach to be extended to normal, non-malignant cells taken
from a patient.
[0132] There are several applications to this approach of targeting
cellular immunity. The first is vaccination against viruses in
which antibodies are known to be required or to enhanced viral
infection. There are two strategies that can be applied here. One
can specifically target the cellular pathway during immunization
thus eliminating the enhancing antibodies. Alternatively one can
vaccinate with the gene for a truncated antigen which eliminates
the humoral epitopes which enhance infectivity.
[0133] The use of DNA or mRNA vaccine therapy could similarly
provide a means to provoke an effective cytotoxic T-cell response
to weakly antigenic tumors. We propose, for example, that if a
tumor-specific antigen were expressed by mRNA inside a cell in an
already processed form, and incorporated directly into the Class I
molecules on the cell surface, a cytotoxic T cell response would be
elicited.
[0134] A second application is that this approach provides a method
to treat latent viral infections. Several viruses (for example,
Hepatitis B, HIV and members of the Herpes virus group) can
establish latent infections in which the virus is maintained
intracellularly in an inactive or partially active form. There are
few ways of treating such infections. However, by inducing a
cytolytic immunity against a latent viral protein, the latently
infected cells will be targeted and eliminated.
[0135] A related application of this approach is to the treatment
of chronic pathogen infections. There are numerous examples of
pathogens which replicate slowly and spread directly from cell to
cell. These infections are chronic, in some cases lasting years or
decades. Examples of these are the slow viruses (e.g. Visna), the
Scrapie agent and HIV. One can eliminate the infected cells by
inducing a cellular response to proteins of the pathogen.
[0136] Finally, this approach may also be applicable to the
treatment of malignant disease. Vaccination to mount a cellular
immune response to a protein specific to the malignant state, be it
an activated oncogene, a fetal antigen or an activation marker,
will result in the elimination of these cells.
[0137] The use of DNA/mRNA vaccines could in this way greatly
enhance the immunogenicity of certain viral proteins, and
cancer-specific antigens, that normally elicit a poor immune
response. The mRNA vaccine technique should be applicable to the
induction of cytotoxic T cell immunity against poorly immunogenic
viral proteins from the Herpes viruses, non-A, non-B hepatitis, and
HIV, and it would avoid the hazards and difficulties associated
with in vitro propagation of these viruses. For cell surface
antigens, such as viral coat proteins (e.g., HIV gp120), the
antigen would be expressed on the surface of the target cell in the
context of the major histocompatibility complex (MHC), which would
be expected to result in a more appropriate, vigorous and realistic
immune response. It is this factor that results in the more
efficacious immune responses frequently observed with attenuated
virus vaccines. Delivery of a single antigen gene by TGT would be
much safer than attenuated viruses, which can result in a low
frequency of disease due to inadequate attenuation.
[0138] There is an additional advantage of TGT which can be
exploited during the vaccine development phase. One of the
difficulties with vaccine development is the requirement to screen
different structural variants of the antigen, for the optimal
immune response. If the variant is derived from a recombinant
source, the protein usually must be expressed and purified before
it can be tested for antigenicity. This is a laborious and time
consuming process. With in vitro mutagenesis, it is possible to
obtain and sequence numerous clones of a given antigen. If these
antigens can be screened for antigenicity at the DNA or RNA level
by TGT, the vaccine development program could be made to proceed
much faster.
[0139] Finally, in the case of the DNA/mRNA vaccines, the protein
antigen is never exposed directly to serum antibody, but is always
produced by the transfected cells themselves following translation
of the mRNA. Hence, anaphylaxis should not be a problem. Thus, the
present invention permits the patient to be immunized repeatedly
without the fear of allergic reactions. The use of the DNA/mRNA
vaccines of the present invention makes such immunization
possible.
[0140] One can easily conceive of ways in which this technology can
be modified to enhance still further the immunogenicity of
antigens. T cell immunization can be augmented by increasing the
density of Class I and Class II histocompatibility antigens on the
macrophage or other cell surface and/or by inducing the transfected
cell to release cytokines that promote lymphocyte proliferation. To
this end, one may incorporate in the same liposomes that contain
mRNA for the antigen, other mRNA species that encode interferons or
interleukin-1. These cytokines are known to enhance macrophage
activation. Their systemic use has been hampered because of side
effects. However, when encapsulated in mRNA, along with mRNA for
antigen, they should be expressed only by those cells that
co-express antigen. In this situation, the induction of T cell
immunity can be enhanced greatly.
[0141] Therapeutic Formulations
[0142] Polynucleotide salts: Administration of pharmaceutically
acceptable salts of the polynucleotides described herein is
included within the scope of the invention. Such salts may be
prepared from pharmaceutically acceptable non-toxic bases including
organic bases and inorganic bases. Salts derived from inorganic
bases include sodium, potassium, lithium, ammonium, calcium,
magnesium, and the like. Salts derived from pharmaceutically
acceptable organic non-toxic bases include salts of primary,
secondary, and tertiary amines, basic amino acids, and the like.
For a helpful discussion of pharmaceutical salts, see S. M. Berge
et al., Journal of Pharmaceutical Sciences 66:1-19 (1977) the
disclosure of which is hereby incorporated by reference.
[0143] Polynucleotides for injection, a preferred route of
delivery, may be prepared in unit dosage form in ampules, or in
multidose containers. The polynucleotides may be present in such
forms as suspensions, solutions, or emulsions in oily or preferably
aqueous vehicles. Alternatively, the polynucleotide salt may be in
lyophilized form for reconstitution, at the time of delivery, with
a suitable vehicle, such as sterile pyrogen-free water. Both liquid
as well as lyophilized forms that are to be reconstituted will
comprise agents, preferably buffers, in amounts necessary to
suitably adjust the pH of the injected solution. For any parenteral
use, particularly if the formulation is to be administered
intravenously, the total concentration of solutes should be
controlled to make the preparation isotonic, hypotonic, or weakly
hypertonic. Nonionic materials, such as sugars, are preferred for
adjusting tonicity, and sucrose is particularly preferred. Any of
these forms may further comprise suitable formulatory agents, such
as starch or sugar, glycerol or saline. The compositions per unit
dosage, whether liquid or solid, may contain from 0.1% to 99% of
polynucleotide material.
[0144] The units dosage ampules or multidose containers, in which
the polynucleotides are packaged prior to use, may comprise an
hermetically sealed container enclosing an amount of polynucleotide
or solution containing a polynucleotide suitable for a
pharmaceutically effective dose thereof, or multiples of an
effective dose. The polynucleotide is packaged as a sterile
formulation, and the hermetically sealed container is designed to
preserve sterility of the formulation until use.
[0145] The container in which the polynucleotide is packaged is
labeled, and the label bears a notice in the form prescribed by a
governmental agency, for example the Food and Drug Administration,
which notice is reflective of approval by the agency under Federal
law, of the manufacture, use, or sale of the polynucleotide
material therein for human administration.
[0146] Federal law requires that the use of pharmaceutical agents
in the therapy of humans be approved by an agency of the Federal
government. Responsibility for enforcement is the responsibility of
the Food and Drug Administration, which issues appropriate
regulations for securing such approval, detailed in 21 U.S.C.
301-392. Regulation for biologic material, comprising products made
from the tissues of animals is provided under 42 U.S.C 262. Similar
approval is required by most foreign countries. Regulations vary
from country to country, but the individual procedures are well
known to those in the art.
[0147] Dosage and Route of Administration
[0148] The dosage to be administered depends to a large extent on
the condition and size of the subject being treated as well as the
frequency of treatment and the route of administration. Regimens
for continuing therapy, including dose and frequency may be guided
by the initial response and clinical judgment. The parenteral route
of injection into the interstitial space of tissues is preferred,
although other parenteral routes, such as inhalation of an aerosol
formulation, may be required in specific administration, as for
example to the mucous membranes of the nose, throat, bronchial
tissues or lungs.
[0149] In preferred protocols, a formulation comprising the naked
polynucleotide in an aqueous carrier is injected into tissue in
amounts of from 10 .mu.l per site to about 1 ml per site. The
concentration of polynucleotide in the formulation is from about
0.1 .mu.g/ml to about 20 mg/ml.
[0150] Regulation of TGT
[0151] Just as DNA based gene transfer protocols require
appropriate signals for transcribing (promoters, enhancers) and
processing (splicing signals, polyadenylation signals) the mRNA
transcript, mRNA based TGT requires the appropriate structural and
sequence elements for efficient and correct translation, together
with those elements which will enhance the stability of the
transfected mRNA.
[0152] In general, translational efficiency has been found to be
regulated by specific sequence elements in the 5' non-coding or
untranslated region (5'UTR) of the RNA. Positive sequence motifs
include the translational initiation consensus sequence (GCC)
ACCATGG (Kozak, Nucleic Acids Res. 15:8125 (1987)) and the .sub.5G
7 methyl GpppG cap structure (Drummond et al., Nucleic Acids Res.
13:7375 (1985)). Negative elements include stable intramolecular 5'
UTR stem-loop structures (Muesing et al., Cell 48:691(1987)) and
AUG sequences or short open reading frames preceded by an
appropriate AUG in the 5' UTR (Kozak, Supra, Rao et al., Mol. and
Cell. Biol. 8:284(1988)). In addition, certain sequence motifs such
as the beta globin 5' UTR may act to enhance translation (when
placed adjacent to a heterologous 5' UTR) by an unknown mechanism.
There are also examples of specific 5' UTR sequences which regulate
eukaryotic translational efficiency in response to environmental
signals. These include the human ferritin 5' UTR (Hentze et al.,
Proc. Natl. Acad. Sci. USA 84:6730 (1987)) and the drosophila
hsp.sup.70 5' UTR (Klemenz et al., EMBO Journal 4:2053 (1985)).
Finally, there are viral 5' UTR sequences which are able to bypass
normal cap dependent translation and translational controls and
mediate an efficient translation of viral or chimeric mRNAs (Dolph
et al., J. of Virol. 62:2059 (1988)), Pelletier and Sonnenberg,
Nature 334, 320 (1988)). mRNA based TGT protocols must therefore
include appropriate 5' UTR translational elements flanking the
coding sequence for the protein of interest.
[0153] In addition to translational concerns, mRNA stability must
be considered during the development of mRNA based TGT protocols.
As a general statement, capping and 3' polyadenylation are the
major positive determinants of eukaryotic mRNA stability (Drummond,
supra; Ross, Mol. Biol. Med. 5:1(1988)) and function to protect the
5' and 3' ends of the mRNA from degradation. However, regulatory
elements which affect the stability of eukaryotic mRNAs have also
been defined, and therefore must be considered in the development
of mRNA TGT protocols. The most notable and clearly defined of
these are the uridine rich 3' untranslated region (3' UTR)
destabilizer sequences found in many short half-life mRNAs (Shaw
and Kamen Cell 46:659 (1986)), although there is evidence that
these are not the only sequence motifs which result in mRNA
destabilization (Kabnick and Housman, Mol. and Cell. Biol. 8:3244
(1988)). In addition, specific regulatory sequences which modulate
cellular mRNA half-life in response to environmental stimuli have
also been demonstrated. These include the estrogen mediated
modulation of Vitellogenin mRNA stability (Brock and Shapiro, Cell
34:207 (1983)), the iron dependent regulation of transferrin
receptor mRNA stability (Mullner and Kuhn, Cell 53:815 (1988))
which is due to a specific 3' UTR motif, the prolactin mediated
control of Casein mRNA stability (Guyette et al., Cell 17:1013
(1989)), the regulation of Fibronectin mRNA stability in response
to a number of stimuli (Dean et al., J. Cell. Biol. 106:2159
(1988)), and the control of Histone mRNA stability (Graves et al.,
Cell 48:615 (1987)). Finally, just as viral RNA sequences have
evolved which bypass normal eukaryotic mRNA translational controls,
likewise some viral RNA sequences seem to be able to confer
stability in the absence of 3' polyadenylation (McGrae and
Woodland, Eur. J. of Biochem. 116: 467 (1981)). Some 5', such as
EMC, according to Example 21, are known to function without a cap.
This cacophony of stability modulating elements must also be
carefully considered in developing mRNA based TGT protocols, and
can be used to modulate the effect of an mRNA treatment.
[0154] Liposome-Forming Materials
[0155] The science of forming liposomes is now well developed.
Liposomes are unilamellar or multilamellar vesicles, having a
membrane portion formed of lipophilic material and an interior
aqueous portion. The aqueous portion is used in the present
invention to contain the polynucleotide material to be delivered to
the target cell. It is preferred that the liposome forming
materials used herein have a cationic group, such as a quaternary
ammonium group, and one or more lipophilic groups, such as
saturated or unsaturated alkyl groups having from about 6 to about
30 carbon atoms. One group of suitable materials is described in
European Patent Publication No. 0187702. These materials have the
formula: 1
[0156] wherein R.sup.1 and R.sup.2 are the same or different and
are alkyl or alkenyl of 6 to 22 carbon atoms, R.sup.3, R.sup.4, and
R.sup.5 are the same or different and are hydrogen, alkyl of 1 to 8
carbons, aryl, aralkyl of 7 to 11 carbons, or when two or three of
R.sup.3, R.sup.4, and R.sup.5 are taken together they form
quinuclidino, piperidino, pyrrolidino, or morpholino; n is 1 to 8,
and X is a pharmaceutically acceptable anion, such as a halogen.
These compounds may be prepared as detailed in the above-identified
patent application; alternatively, at least one of these compounds,
N-(2,3-di-(9-(Z)-octadecenyloxy))-prop-1-yl-
-N,N,N-trimethylammonium chloride (DOTMA), is commercially
available from Bethesda Research Laboratories (BRL), Gaithersburg,
Md. 20877, USA.
[0157] These quaternary ammonium diether compounds, however, do
have some drawbacks. Because of the ether linkages, they are not
readily metabolized in vivo. When long-term therapy is
contemplated, there is some possibility that these materials could
accumulate in tissue, ultimately resulting in lipid storage disease
and toxic side effects. Accordingly, a preferred class of
compositions for use in the present invention has the formula:
2
[0158] wherein R.sup.1 and R.sup.2 are the same or different and
are alkyl or alkenyl of 5 to 21 carbon atoms, R.sup.3, R.sup.4, and
R.sup.5 are the same or different and are hydrogen, alkyl of 1 to 8
carbons, aryl, aralkyl of 7 to 11 carbons, or when two or three of
R.sup.3, R.sup.4, and R.sup.5 are taken together they form
quinuclidino, piperidino, pyrrolidino, or morpholino; n is 1 to 8,
and X is a pharmaceutically acceptable anion, such as a halogen.
These compounds may be prepared using conventional techniques, such
as nucleophilic substitution involving a carboxylic acid and an
alkyl halide, by transesterification, or by condensation of an
alcohol with an acid or an acid halide.
[0159] Moreover, many suitable liposome-forming cationic lipid
compounds are described in the literature. See, e.g., L.
Stamatatos, et al., Biochemistry 27:3917-3925 (1988); H. Eibl, et
al., Biophysical Chemistry 10:261-271 (1979).
[0160] Liposome Preparation
[0161] Suitable liposomes for use in the present invention are
commercially available. DOTMA liposomes, for example, are available
under the trademark Lipofectin from Bethesda Research Labs,
Gaithersburg, Md.
[0162] Alternatively, liposomes can be prepared from
readily-available or freshly synthesized starting materials of the
type previously described. The preparation of DOTAP liposomes is
detailed in Example 6. Preparation of DOTMA liposomes is explained
in the literature, see, e.g., P. Felgner, et al., Proc. Nat'l Acad.
Sci. USA 84:7413-7417. Similar methods can be used to prepare
liposomes from other cationic lipid materials. Moreover,
conventional liposome forming materials can be used to prepare
liposomes having negative charge or neutral charge. Such materials
include phosphatidyl choline, cholesterol,
phosphatidyl-ethanolamine, and the like. These materials can also
advantageously be mixed with the DOTAP or DOTMA starting materials
in ratios from 0% to about 75%.
[0163] Conventional methods can be used to prepare other,
noncationic liposomes. These liposomes do not fuse with cell walls
as readily as cationic liposomes. However, they are taken up by
macrophages in vivo, and are thus particularly effective for
delivery of polynucleotide to these cells. For example,
commercially-available dioleoyl-phosphatidyl choline (DOPC),
dioleoylphosphatidyl glycerol (DOPG), and dioleoylphosphatidyl
ethanolamine (DOPE) can be used in various combinations to make
conventional liposomes, with or without the addition of
cholesterol. Thus, for example, DOPG/DOPC vesicles can be prepared
by drying 50 mg each of DOPG and DOPC under a stream of nitrogen
gas into a sonication vial. The sample is placed under a vacuum
pump overnight and is hydrated the following day with deionized
water. The sample is then sonicated for 2 hours in a capped vial,
using a Heat Systems model 350 sonicator equipped with an inverted
cup (bath type) probe at the maximum setting while the bath is
circulated at 15.degree. C. Alternatively, negatively charged
vesicles can be prepared without sonication to produce
multilamellar vesicles or by extrusion through nucleopore membranes
to produce unilamellar vesicles of discrete size. Other methods are
known and available to those of skill in the art.
[0164] The present invention is described below in detail using the
23 examples given below; however, the methods described are broadly
applicable as described herein and are not intended to be limited
by the Examples.
EXAMPLE 1
Preparation of Liposome-Forming DOTAP
[0165] The cationic liposome-forming material
1,2-bis(oleoyloxy)-3-(trimet- hylammonio)propane (DOTAP) is
prepared as reported by L. Stamatatos, et al. (supra) or H. Eibl,
et al. (supra).
[0166] Briefly, Stamatatos, et al. report that 1 mmol of
3-bromo-1,2-propanediol (Aldrich) was acylated for 48 hours at
20.degree. C. with 3 mmol of oleyl chloride (freshly prepared from
oleic acid and oxaloyl chloride) in dry, alcohol-free diethyl ether
(20 ml) containing 5 mmol of dry pyridine. The precipitate of
pyridinium hydrochloride was filtered off, and the filtrate was
concentrated under nitrogen and redissolved in 10 ml of hexane. The
hexane solution was washed 3 times with an equal volume of 1:1
methanol/0.1 N aqueous NCOONa, pH 3.0, 3 times with 1:1
methanol/0.1 N aqueous NaOH, and 1 time with 1% aqueous NaCl. The
crude 3-bromo-1,2-bis-(oleolyloxy)propane was then stirred for 72
hours in a sealed tube with a solution of 15% trimethylamine in dry
dimethyl sulfoxide (30 ml) at 25.degree. C. The products of this
reaction were dissolved in chloroform (200 ml), which was
repeatedly washed with 1:1 methanol/100 mM aqueous HCOONa, pH 3.0,
and then evaporated in vacuo to yield a light yellow oil. This
material was purified on a column of silicic acid (Bio-Sil A,
Bio-Rad Laboratories), eluting with a 0-15% gradient of methanol in
chloroform to give the desired product in pure form at 9-10%
methanol. The purified product was a colorless, viscous oil that
migrates with an R.sub.f of 0.4 on thin layer chromatography plates
(silica gel G) that were developed with 50:15:5:5:2
CHCl.sub.3/acetone/CH.sub.3OH/CH.sub.3COOH/H.sub.2O.
EXAMPLE 2
Preparation of Plasmids for Making DNA Templates for any Gene of
Interest
[0167] Suitable template DNA for production of mRNA coding for a
desired polypeptide may be prepared in accordance with standard
recombinant DNA methodology. As has been previously reported (P.
Kreig, et al., Nucleic Acids Res. 12:7057-7070 (1984)), a 5' cap
facilitates translation of the mRNA. Moreover, the 3' flanking
regions and the poly A tail are believed to increase the half life
of the mRNA in vivo.
[0168] The readily-available SP6 cloning vector pSP64T provides 5'
and 3' flanking regions from .beta.-globin, an efficiently
translated mRNA. The construction of this plasmid is detailed by
Kreig, et al. (supra), and is hereby incorporated by this
reference. Any cDNA containing an initiation codon can be
introduced into this plasmid, and mRNA can be prepared from the
resulting template DNA. This particular plasmid can be cut with
BglII to insert any desired cDNA coding for a polypeptide of
interest.
[0169] Although good results can be obtained with pSP64T when
linearized and then transcribed in vivo with SP6 RNA polymerase, we
prefer to use the Xenopus .beta.-globin flanking sequences of
pSP64T with phage T7 RNA polymerase. These flanking sequences are
purified from pSP64T as the small (approx. 150 bp) HindIII to EcoRI
fragment. These sequences are then inserted into a purified linear
HindIII/EcoRI fragment (approx. 2.9 k bp) from pIBI 31
(commercially available from International Biotechnologies, Inc.,
Newhaven, Conn. 06535) with T4 DNA ligase. Resulting plasmids,
designated pXBG, are screened for orientation and transformed into
E. coli. These plasmids are adapted to receive any gene of interest
at a unique BglII restriction site, which is situated between the
two xenopus .beta.-globin sequences.
EXAMPLE 3
Preparation of Plasmid Coding for Chloramphenicol
Acetyltransferase
[0170] A convenient marker gene for demonstrating in vivo
expression of exogenous polynucleotides is chloramphenicol
acetyltransferase, CAT. A plasmid pSP-CAT containing the CAT gene
flanked by the xenopus .beta.-globin 5' and 3' sequences was
produced by adding the CAT gene into the BgIII site of pSP64T. We
used CAT gene in the form of the small BamHI/HindIII fragment from
pSV2-CAT (available from the American Type Culture Collection,
Rockville, Md., Accession No. 37155). However, the CAT gene is
commonly used in molecular biology and is available from numerous
sources. Both the CAT BamHI/HindIII fragment and the BgIII-cleaved
pSP64T were incubated with the Klenow fragment to generate blunt
ends, and were then ligated with T4 DNA ligase to form pSP-CAT.
[0171] The small PstI/HindIII fragment was then generated and
purified, which comprises the CAT gene between the 5' and 3'
.beta.-globin flanking sequences of pSP64T. pIBI31 (International
Biotechnologies, Inc.) was cleaved with PstI and HindIII, and the
long linear sequence was purified. This fragment was then combined
with the CAT-gene containing sequence and the fragments were
ligated with T4 DNA ligase to form a plasmid designated pT7CAT An.
Clones are selected on the basis of .beta.-galactosidase activity
with Xgal and ampicillin resistance.
EXAMPLE 4
Preparation of Purified DNA Template
[0172] The plasmid DNA from Example 3 is grown up and prepared as
per Maniatis (supra), except without RNAse, using 2 CsCl spins to
remove bacterial RNA. Specifically, E. coli containing pT7CAT An
from Example 3 was grown up in ampicillin-containing LB medium. The
cells were then pelleted by spinning at 5000 rpm for 10 min. in a
Sorvall RC-5 centrifuge (E. I. DuPont, Burbank, Calif. 91510),
resuspended in cold TE, pH 8.0, centrifuged again for 10 min. at
5000 rpm., resuspended in a solution of 50 mM glucose, 25 mM
Tris-Cl pH 8.0, 10 mM EDTA, and 40 mg/ml lysozyme. After incubation
for 5 to 10 minutes with occasional inversion, 0.2 N NaOH
containing 1% SDS was added, followed after 10 minutes at 0.degree.
C. with 3 M potassium acetate and 2 M acetic acid. After 10 more
minutes, the material was again centrifuged at 6000 rpm, and the
supernatant was removed with a pipet. The pellet was then mixed
into 0.6 vol. isopropanol (-20.degree. C.), mixed, and stored at
-20.degree. C. for 15 minutes. The material was then centrifuged
again at 10,000 rpm for 20 min., this time in an HB4 swinging
bucket rotor apparatus (DuPont, supra) after which the supernatant
was removed and the pellet was washed in 70% EtOH and dried at room
temperature. Next, the pellet was resuspended in 3.5 ml TE,
followed by addition of 3.4 g CsCl and 350 .mu.l of 5 mg/ml EtBr.
The resulting material was placed in a quick seal tube, filled to
the top with mineral oil. The tube was spun for 3.5 hours at 80,000
rpm in a VTi80 centrifuge (Beckman Instruments, Pasadena, Calif.,
91051). The band was removed, and the material was centrifuged
again, making up the volume with 0.95 g CsCl/ml and 0.1 ml or 5
mg/ml EtBr/ml in TE. The EtBr was then extracted with an equal
volume of TE saturated N-Butanol after adding 3 volumes of TE to
the band, discarding the upper phase until the upper phase is
clear. Next, 2.5 vol. EtOH was added, and the material was
precipitated at -20 C for 2 hours. The resultant DNA precipitate is
used as a DNA template for preparation of mRNA in vitro.
EXAMPLE 5
Preparation of mRNA for Transfection
[0173] The DNA from Example 4 was linearized downstream of the poly
A tail with a 5-fold excess of PstI. The linearized DNA was then
purified with two phenol/chloroform extractions, followed by two
chloroform extractions. DNA was then precipitated with NaOAc (0.3
M) and 2 volumes of EtOH. The pellet was resuspended at about 1
mg/ml in DEP-treated deionized water.
[0174] Next, a transcription buffer was prepared, comprising 400 mM
Tris HCl (pH 8.0), 80 mM MgCl.sub.2, 50 mM DTT, and 40 mM
spermidine. Then, the following materials were added in order to
one volume of DEP-treated water at room temperature: 1 volume T7
transcription buffer, prepared above; rATP, rCTP, and rUTP to 1 mM
concentration; rGTP to 0.5 mM concentration; 7 meG (5') ppp (5') G
cap analog (New England Biolabs, Beverly, Mass., 01951) to 0.5 mM
concentration; the linearized DNA template prepared above to 0.5
mg/ml concentration; RNAsin (Promega, Madison, Wis.) to 2000 U/ml
concentration; and T7 RNA polymerase (N.E. Biolabs) to 4000 U/ml
concentration.
[0175] This mixture was incubated for 1 hour at 37 C. The
successful transcription reaction was indicated by increasing
cloudiness of the reaction mixture.
[0176] Following generation of the mRNA, 2 U RQ1 DNAse (Promega)
per microgram of DNA template used was added and was permitted to
digest the template for 15 minutes. Then, the RNA was extracted
twice with chloroform/phenol and twice with chloroform. The
supernatant was precipitated with 0.3 M NaOAc in 2 volumes of EtOH,
and the pellet was resuspended in 100 .mu.l DEP-treated deionized
water per 500 .mu.l transcription product. This solution was passed
over an RNAse-free Sephadex G50 column (Boehringer Mannheim #100
411). The resultant mRNA was sufficiently pure to be used in
transfection of vertebrates in vivo.
EXAMPLE 6
Preparation of Liposomes
[0177] A number of liposome preparation methods can be used to
advantage in the practice of the present invention. One
particularly preferred liposome is made from DOTAP as follows:
[0178] A solution of 10 mg dioleoyl phosphatidylethanolamine (PE)
and 10 mg DOTAP (from Example 1) in 1 ml chloroform is evaporated
to dryness under a stream of nitrogen, and residual solvent is
removed under vacuum overnight. Liposomes are prepared by
resuspending the lipids in deionized water (2 ml) and sonicating to
clarity in a closed vial. These preparations are stable for at
least 6 months.
[0179] Polynucleotide complexes were prepared by mixing 0.5 ml
polynucleotide solution (e.g., from Example 5) at 0.4 mg/ml by slow
addition through a syringe with constant gentle vortexing to a 0.5
ml solution of sonicated DOTMA/PE or DOTAP/PE liposomes at 20
mg/ml, at room temperature. This procedure results in positively
charged complexes which will spontaneously deliver the
polynucleotide into cells in vivo. Different ratios of positively
charged liposome to polynucleotide can be used to suit the
particular need in any particular situation. Alternatively, as
reported by Felgner, et al. (supra), it may be advantageous to
dilute the polynucleotide (DNA or RNA) with Hepes buffered saline
(150 mM NaCl; 20 mM Hepes, pH 7.4) prior to combining the materials
to spontaneously form liposome/polynucleotide complexes. In many
instances, however, the use of solutions having low ionic strength
(such as sucrose) instead of saline solution is believed to be
preferable; in particular, it is believed that such solutions
facilitate delivery of polynucleotide to the cell by minimizing
precipitation of polynucleotide/lipid complex.
EXAMPLE 7
In Vivo Expression of Liposomally and Non-Liposomally Introduced
mRNA in the Rat
[0180] The ability of mRNA coding for chloramphenicol acetyl
transferase (CAT) to transfect cells in vivo and the subsequent
expression of the CAT protein was demonstrated by directly
injecting 0.200 ml of each of the formulations below, prepared as
indicated, into the abdominal muscle of rats, forming a bleb. Six
replicates of each formulation were tested. After 12 to 14 h, the
segment of the abdominal muscle into which the injection was made,
weighing approximately 0.1 to 0.2 grams, was excised, minced, and
placed in a 1.5 ml disposable mortar (Kontes, Morton Grove, Ill.)
together with 200 .mu.l of an aqueous formulation having the
following components: 20 mM Tris, pH 7.6; 2 mM MgCl.sub.2; and 0.1%
Triton X-100 surfactant. The contents of the mortar were then
ground for 1 minute with a disposable pestle. The mortar was then
covered (with Parafilm) and placed in a 1 liter Parr cell disrupter
bomb (Parr Instrument Company, Moline, Ill.) and pressurized to 6
atmospheres with nitrogen at 4.degree. C. After 30 minutes, the
pressure was quickly released to disrupt the tissue and produce a
crude lysate. The lysate was then centrifuged in a microcentrifuge
at 13,000 rpm, 4.degree. C., for 10 minutes. The supernatant was
then decanted and stored at -20.degree. C. until analyzed.
[0181] The lysates were then assayed for the presence of the CAT
protein by thin-layer chromatography. First, 75 pl of each sample
(the supernatant prepared above) was incubated for two hours at
37.degree. C. with 5 .mu.l C14 chloramphenicol (Amersham); 20 .mu.l
4 mM Acetyl CoA; and 50 .mu.l 1 M Tris, pH 7.8. Thereafter, 20 pl
of 4 mM Acetyl CoA was added, and the mixture was again incubated
for 2 hours at 37.degree. C. The resulting solution was extracted
with 1 ml EtOAc, and the organic phase was removed and lyophilized
in a vacuum centrifuge (SpeedVac, Savant Co.). The pellet was
resuspended in 20 .mu.l EtOAc, and was spotted onto a silica gel
thin layer chromatography plate. The plate was developed for 45
minutes in 95% chloroform/5% methanol, was dried, and was sprayed
with a radioluminescent indicator (Enhance Spray for Surface
Radiography, New England Nuclear Corp.). The plate was then
sandwiched with Kodak XAR5 film with overnight exposure at
-70.degree. C., and the film was developed per manufacturer's
instructions. The following results were obtained:
1 mRNA Expression FORMULATION (No. positive/total) 1. 1 ml Optimem;
37.5 .mu.g DOTMA 0/6 2. 1 ml Optimem; 15 .mu.g CAT RNA 3/6 3.
Formulation 1 plus 15 .mu.g CAT RNA 4/6 4. 10% Sucrose; 37.5 .mu.g
DOTMA; 15 .mu.g CAT RNA 3/6 5. 10% Sucrose; 187 .mu.g DOTMA; 75
.mu.g CAT RNA 0/6
[0182] Optimem: Serum-free media (Gibco Laboratories, Life
Technologies, Inc, Grand Island, N.Y. 14072)
[0183] DOTMA: (Lipofectin brand; Bethesda Research Labs,
Gaithersburg, Md.)
[0184] CAT RNA: From Example 5
[0185] All formulations made up in DEPC-treated RNAse-free water
(International Biotechnologies, Inc., New Haven, Conn. 06535).
EXAMPLE 8
mRNA Vaccination of Mice to Produce the gp120 Protein of HIV
Virus
[0186] A liposomal formulation containing mRNA coding for the gp120
protein of the HIV virus is prepared according to Examples 1
through 5, except that the gene for gp120 (pIIIenv3-1 from the Aids
Research and Reagent Program, National Institute of Allergy and
Infectious Disease, Rockville, Md. 20852) is inserted into the
plasmid pXBG in the procedure of Example 4. A volume of 200 .mu.l
of a formulation, prepared according to Example 6, and containing
200 .mu.g/ml of gp120 mRNA and 500 .mu.g/ml 1:1 DOTAP/PE in 10%
sucrose is injected into the tail vein of mice 3 times in one day.
At about 12 to 14 h after the last injection, a segment of muscle
is removed from the injection site, and prepared as a cell lysate
according to Example 7. The HIV specific protein gp120 is
identified in the lysate also according to the procedures of
Example 7.
[0187] The ability of gp120 antibody present in serum of the mRNA
vaccinated mice to protect against HIV infection is determined by a
HT4-6C plaque reduction assay, as follows:
[0188] HT4-6C cells (CD4+HeLa cells) are obtained from Dr. Bruce
Chesebro, (Rocky Mountain National Lab, Montana) and grown in
culture in RPMI media (BRL, Gaithersburg, Md.). The group of cells
is then divided into batches. Some of the batches are infected with
HIV by adding approximately 105 to 106 infectious units of HIV to
approximately 107 HT4-6C cells. Other batches are tested for the
protective effect of gp120 immune serum against HIV infection by
adding both the HIV and approximately 50 .mu.l of serum from a
mouse vaccinated with gp120 mRNA. After 3 days of incubation, the
cells of all batches are washed, fixed and stained with crystal
violet, and the number of plaques counted. The protective effect of
gp120 immune serum is determined as the reduction in the number of
plaques in the batches of cells treated with both gp120
mRNA-vaccinated mouse serum and HIV compared to the number in
batches treated with HIV alone.
EXAMPLE 9
mRNA Vaccination of Human Stem Cell-Bearing SCID Mice with NEF mRNA
Followed by HIV Challenge
[0189] Severe combined immunodeficient mice (SCID mice (Molecular
Biology Institute, (MBI), La Jolla, Calif. 92037)) were
reconstituted with adult human peripheral blood lymphocytes by
injection into the peritoneal cavity according to the method of
Mosier (Mosier et al., Nature 335:256 (1988)). Intraperitoneal
injection of 400 to 4000 infectious units of HIV-1 was then
performed. The mice were maintained in a P3 level animal
containment facility in sealed glove boxes.
[0190] mRNA coding for the Nef protein if HIV was prepared by
obtaining the nef gene in the form of a plasmid (pGM92, from the
NIAID, Rockville, Md. 20852); removing the nef gene from the
plasmid; inserting the nef gene in the pXBG plasmid for
transcription; and purifying the transcription product nef mRNA as
described in Examples 2 through 5. The nef mRNA was then
incorporated into a formulation according to Example 6. 200
microliter tail vein injections of a 10% sucrose solution
containing 200 .mu.g/ml NEF RNA and 500 .mu.g/ml 1:1 DOTAP:DOPE (in
RNA/liposome complex form) were performed daily on experimental
animals, while control animals were likewise injected with
RNA/liposome complexes containing 200 .mu.g/ml yeast tRNA and 500
.mu.g/ml 1:1 DOTAP/DOPE liposomes. At 2, 4 and 8 weeks post
injection, biopsy specimens were obtained from injected lymphoid
organs and prepared for immunohistochemistry. At the same time
points, blood samples were obtained and assayed for p24 levels by
means of an ELISA kit (Abbott Labs, Chicago, Ill.) and virus titer
by the plaque assay of Example 8. Immunostaining for HIV-1 was
performed as described (Namikawa et al., Science 242:1684 (1988))
using polyclonal serum from a HIV infected patient. Positive cells
were counted and the number of infected cells per high power field
(400.times.) were determined. Using these assays, at least a 2 fold
reduction in the number of positive staining cells was observed at
8 weeks, and titer and p24 expression was reduced by at least 50%.
Together, these results indicate a moderate anti-viral effect of
the (in vivo) treatment.
[0191] A volume of 200 .mu.l of the formulation, containing 200
.mu.g/ml of nef mRNA, and 500 .mu.g/ml 1:1 DOTAP:DOPE in 10%
sucrose is injected into the tail vein of the human stem
cell-containing SCID mice 3 times in one day. Following
immunization, the mice are challenged by infection with an
effective dose of HIV virus. Samples of blood are periodically
withdrawn from the tail vein and monitored for production of the
characteristic HIV protein p24 by an ELISA kit assay (Abbott Labs,
Chicago, Ill.).
EXAMPLE 10
A Method of Providing Adenosine Deaminase to Mice by In Vivo mRNA
Transfection
[0192] The full-length sequence for the cDNA of the human adenosine
deaminase (ADA) gene is obtained from the 1,300 bp EcoR1-AccI
fragment of clone ADA 211 (Adrian, G. et al. Mol. Cell Biol. 4:1712
(1984). It is blunt-ended, ligated to BgIII linkers and then
digested with BgIII. The modified fragment is inserted into the
BgIII site of pXBG. ADA mRNA is transcribed and purified according
to Examples 2 through 5, and purified ADA mRNA is incorporated into
a formulation according to Example 6. Balb 3T3 mice are injected
directly in the tail vein with 200 pl of this formulation,
containing 200 .mu.g/ml of ADA mRNA, and 500 .mu.g/ml DOTAP in 10%
sucrose.
[0193] The presence of human ADA in the tissues of the liver, skin,
and muscle of the mice is confirmed by an isoelectric focusing
(IEF) procedure. Tissue extracts were electrofocused between pH 4
and 5 on a non-denaturing gel. The gel was then stained for in situ
ADA activity as reported by Valerio, D. et al. Gene 31:137-143
(1984).
[0194] A preliminary separation of human and non-human ADA is
carried out by fast protein liquid chromatography (FPLC). The
proteins are fractionated on a Pharmacia (Piscataway, N.J.) MonoQ
column (HR5/5) with a linear gradient from 0.05 to 0.5 M KCl, 20 mM
Tris (pH 7.5). Activity for ADA within the fractions is measured by
reacting the fractions with .sup.14C-adenosine (Amersham, Chicago,
Ill.) which is converted to inosine. Thin layer chromatography (0.1
M NaPi pH 6.8 saturated ammonium sulfate:n-propylalcohol/100:60:2)
is used to separate the radioactive inosine from the substrate
adenosine.
EXAMPLE 11
In Vivo Expression of Pure RNA and DNA Injected Directly into the
Muscles of Mice
[0195] The quadriceps muscles of mice were injected with either 100
.mu.g of pRSVCAT DNA plasmid or 100 .mu.g of
.beta.gCAT.beta.gA.sub.n RNA and the muscle tissue at the injection
site later tested for CAT activity.
[0196] Five to six week old female and male Balb/C mice were
anesthetized by intraperitoneal injection with 0.3 ml of 2.5%
Avertin. A 1.5 cm incision was made on the anterior thigh, and the
quadriceps muscle was directly visualized. The DNA and RNA were
injected in 0.1 ml of solution in a 1 cc syringe through a 27 gauge
needle over one minute, approximately 0.5 cm from the distal
insertion site of the muscle into the knee and about 0.2 cm deep. A
suture was placed over the injection site for future localization,
and the skin was then closed with stainless steel clips.
[0197] 3T3 mouse fibroblasts were also transfected in vitro with 20
.mu.g of DNA or RNA complexed with 60 .mu.g of Lipofectin.TM. (BRL)
in 3 ml of Opti-Mem.TM. (Gibco), under optimal conditions described
for these cells (Malone, R. et al. Proc. Nat'l. Acad. Sci. USA
86:6077-6081(1989). The same fibroblasts were also transfected
using calcium phosphate according to the procedure described in
Ausubel et al.(Eds) Current Protocols in Molecular Biology, John
Wiley and Sons, New York (1989).
[0198] The pRSVCAT DNA plasmid and .beta.gCAT.beta.gA.sub.n RNA
were prepared as described in the preceding examples. The RNA
consisted of the chloramphenicol acetyl transferase (CAT) coding
sequences flanked by 5' and 3' .beta.-globin untranslated sequences
and a 3' poly-A tract.
[0199] Muscle extracts were prepared by excising the entire
quadriceps, mincing the muscle into a 1.5 ml microtube containing
200 pl of a lysis solution (20 mM Tris, pH 7.4, 2 mM MgCl.sub.2 and
0.1% Triton X), and grinding the muscle with a plastic pestle
(Kontes) for one minute. In order to ensure complete disruption of
the muscle cells, the muscle tissue was then placed under 600 psi
of N.sub.2 in a bomb (Parr) at 4.degree. C. for 15 min before
releasing the pressure.
[0200] Fibroblasts were processed similarly after they were
trypsinized off the plates, taken up into media with serum, washed
2.times.with PBS, and the final cell pellet suspended into 200
.mu.l of lysis solution. 75 .mu.l of the muscle and fibroblast
extracts were assayed for CAT activity by incubating the reaction
mixtures for 2 hours with .sup.14C-chloramphenicol, followed by
extraction and thin-layer chromatography, all as described in
Example 7.
[0201] FIG. 1 comprises autoradiograms from two separate
experiments showing CAT activity within extracts of the injected
quadriceps muscles.
[0202] Lane numbers appear at the top of the autoradiograms and the
% chloramphenicol conversions are at the bottom. Sample locations
are as follows:
[0203] Lanes 1 and 13: Control fibroblasts
[0204] Lanes 2 and 14: Muscle injected only with 5% sucrose
[0205] Lanes 3 and 15: 0.005 units of non-injected, purified CAT
standard
[0206] Lanes 4 and 16: 0.05 units of purified CAT (Sigma)
[0207] Lanes 5 to 8: Muscle injected with 100 .mu.g of
.beta.gCAT.beta.gA.sub.n RNA in 5% sucrose
[0208] Lanes 11, 12, and 17 to 20: Muscle injected with 100
.mu.grams pRSVCAT DNA in 5% sucrose
[0209] Lanes 9 and 10: 20 .mu.grams of .beta.gCAT.beta.gA.sub.n
RNA, lipofected, with 60 .beta.grams of DOTMA, into a 70% confluent
60 mm plate of 3T3 cells (10.sup.6)
[0210] Lanes 21, 22: 20 .mu.grams of pRSVCAT lipofected, with 60
.mu.g of DOTMA, into a 50% confluent 60 mm plate of 3T3 cells
[0211] Lanes 23, 24: 20 .mu.g of pRSVCAT calcium phosphate
lipofected into a 50% confluent 60 mm plate of 3T3 cells.
[0212] CAT activity was readily detected in all four RNA injection
sites 18 hours after injection and in all six DNA injection sites
48 hours after injection. Extracts from two of the four RNA
injection sites (FIG. 1, lanes 6 and 8) and from two of the six DNA
injection sites (FIG. 1, lanes 11 and 20) contained levels of CAT
activity comparable to the levels of CAT activity obtained from
fibroblasts transiently transfected in vitro under optimal
conditions (FIG. 1, lanes 9, 10, 21-24). The average total amount
of CAT activity expressed in muscle was 960 pg for the RNA
injections and 116 pg for the DNA injections. The variability in
CAT activity recovered from different muscle sites probably
represents variability inherent in the injection and extraction
technique, since significant variability was observed when pure CAT
protein or pRSVCAT-transfected fibroblasts were injected into the
muscle sites and immediately excised for measurement of CAT
activity. CAT activity was also recovered from abdominal muscle
injected with the RNA or DNA CAT vectors, indicating that other
muscle groups can take up and express polynucleotides.
EXAMPLE 12
Site of In Vivo Expression of Pure DNA Injected Directly into the
Muscles of Mice
[0213] The site of gene expression in injected muscle was
determined by utilizing the pRSVLac-Z DNA vector (P. Norton and J.
Coffin Molec. Cell Biol. 5:281-290 (1985)) expressing the E.
coli-galactosidase gene for injection and observing the in situ
cytochemical staining of muscle cells for E. coli
.beta.-galactosidase activity. The quadriceps muscle of mice was
exposed as described in the previous example. Quadriceps muscles
were injected once with 100 .mu.g of pRSVLAC-Z DNA in 20% sucrose.
Seven days later the individual quadriceps muscles were removed in
their entirety and every fifth 15 .mu.m cross-section was
histochemically stained for .beta.-galactosidase activity.
[0214] The muscle biopsy was frozen in liquid N.sub.2-cooled
isopentane. 15 .mu.m serial sections were sliced using a cryostat
and placed immediately on gelatinized slides. The slide were fixed
in 1.5% glutaraldehyde in PBS for 10 minutes and stained 4 hours
for .beta.-galactosidase activity (J. Price et al. Proc. Nat'l
Acad. Sci. USA 84:156-160 (1987). The muscle was counterstained
with eosin.
[0215] The photographed sections (FIG. 2) are as follows:
[0216] (A) and (B): Cross-sections of a muscle injected with
pRSVLacZ at 25.times.and 160.times. magnification,
respectively.
[0217] (C): A longitudinal section of another muscle injected with
pRSVLacZ, 160.times..
[0218] (D), (E), and (F): Serial cross-sections of the same muscle
that are 0.6 mm apart.
[0219] Approximately 60 muscle cells of the approximately 4000
cells (1.5%) that comprise the entire quadriceps and approximately
10-30% of the cells within the injection area were stained blue
(FIGS. 2A and 2B). Control muscle injected with only a 20% sucrose
solution did not show any background staining. Positive
.beta.-galactosidase staining within some individual muscle cells
was at least 1.2 mm deep on serial cross-sections (FIGS. 2D, 2E,
and 2F), which may be the result of either transfection into
multiple nuclei or the ability of cytoplasmic proteins expressed
from one nucleus to be distributed widely within the muscle cell.
Longitudinal sectioning also revealed .beta.-galactosidase staining
within muscle cells for at least 400 mm (FIG. 2C). In cells
adjacent to intensely blue cells, fainter blue staining often
appeared in their bordering areas. This most likely represents an
artifact of the histochemical .beta.-galactosidase stain in which
the reacted X-gal product diffuses before precipitating.
[0220] Similar results are obtained with linear DNA.
EXAMPLE 13
Dose-Response Effects of RNA and DNA Injected Into Muscles of
Mice
[0221] Experiments with the firefly luciferase reporter gene (LUC)
explored the effect of parameters of dose level and time on the
total luciferase extracted from injected muscle.
[0222] The RNA and DNA vectors were prepared, and the quadriceps
muscles of mice injected as previously described. Muscle extracts
of the entire quadriceps were prepared as described in Example 11,
except that the lysis buffer was 100 mM KPi pH 7.8, 1 mM DTT, and
0.1% Triton X. 87.5 .mu.l of the 200 .mu.l extract was analyzed for
luciferase activity (J. de Wet et al. Molec. Cell Biol.
7:725-737(1987)) using an LKB .sup.125I luminometer. Light units
were converted to picograms (pg) of luciferase using a standard
curve established by measuring the light units produced by purified
firefly luciferase (Analytical Luminescence Laboratory) within
control muscle extract. The RNA and DNA preparations prior to
injection did not contain any contaminating luciferase activity.
Control muscle injected with 20% sucrose had no detectable
luciferase activity. All the above experiments were done two to
three times and specifically, the DNA time points greater than 40
days were done three times.
[0223] The FIGS. 3A to 3C illustrate the results of the
following:
[0224] 3(A) Luciferase activity measured 18 hours following the
injection of varying amounts of 'RNA in 20% sucrose and 4 days
following the injection of varying amounts of pRSVL in 20%
sucrose
[0225] 3(B) Luciferase activity assayed at varying times after 20
.mu.g of .beta.gLUC.beta.gA.sub.n RNA were lipofected into a
million 3T3 fibroblasts (Malone, R. et al. Proc. Nat'l. Acad. Sci.
USA 86:6077-6081 (1989), and after 100 .mu.g of
.beta.gLUC.beta.gA.sub.n RNA in 20% sucrose were injected into
quadriceps.
[0226] 3(C) Luciferase activity assayed at varying times after
pRSVL DNA was injected intramuscularly.
[0227] A. Level of Gene Expression
[0228] A dose-response effect was observed when quadriceps muscles
were injected with various amounts of .beta.gLuc.beta.gA.sub.n RNA
or DNA pRSVL constructs (FIG. 3A). The injection of ten times more
DNA resulted in luciferase activity increasing approximately
ten-fold from 33 pg luciferase following the injection of 10 .mu.g
of DNA to 320 pg luciferase following the injection of 100 .mu.g of
DNA. The injection of ten times more RNA also yielded approximately
ten times more luciferase. A million 3T3 mouse fibroblasts in a 60
mm dish were lipofected with 20 .mu.g of DNA or RNA complexed with
60 .mu.g of Lipofectin.TM. (Bethesda Research Labs) in 3 ml of
Opti-MEM.TM. (Gibco). Two days later, the cells were assayed for
luciferase activity and the results from four separate plates were
averaged. Twenty .mu.g of pRSVL DNA transfected into fibroblasts
yielded a total of 120 pg of luciferase (6 pg luciferase/.mu.g
DNA), while 25 .mu.g injected into muscle yielded an average of 116
pg of luciferase (4.6 pg luciferase/.mu.g DNA; FIG. 3A). The
expression from the RNA vectors was approximately seven-fold more
efficient in transfected fibroblasts than in injected muscles.
Twenty .mu.g of .beta.gLuc.beta.gA.sub.n RNA transfected into
fibroblasts yielded a total of 450 pg of luciferase, while 25 .mu.g
injected into muscle yielded 74 pg of luciferase (FIGS. 3A and
3B).
[0229] Based on the amount of DNA delivered, the efficiency of
expression from the DNA vectors was similar in both transfected
fibroblasts and injected muscles.
[0230] B. Time Course of Expression
[0231] The time course was also investigated (FIGS. 3B and 3C).
Luciferase activity was assayed at varying times after 25 pg of
.beta.gLuc.beta.gA.sub.n RNA or 100 .mu.g of pRSVL DNA were
injected. Following RNA injection, the average luciferase activity
reached a maximum of 74 pg at 18 hours, and then quickly decreased
to 2 pg at 60 hours. In transfected fibroblasts, the luciferase
activity was maximal at 8 hours. Following DNA injection into
muscle, substantial amounts of luciferase were present for at least
60 days.
[0232] The data in FIG. 3B suggest that luciferase protein and the
in vitro RNA transcript have a half-life of less than 24 hours in
muscle. Therefore, the persistence of luciferase activity for 60
days is not likely to be due to the stability of luciferase protein
or the stability of the in vivo RNA transcript.
EXAMPLE 14
Persistence of DNA in Muscle Following Injection as Determined by
Southern Blot Analysis
[0233] Preparations of muscle DNA were obtained from control,
uninjected quadriceps or from quadriceps, 30 days after injection
with 100 .mu.g of pRSVL in 20% sucrose. Two entire quadriceps
muscles from the same animal were pooled, minced into liquid
N.sub.2 and ground with a mortar and pestle. Total cellular DNA and
HIRT supernatants were prepared (F. M. Ausubel et al.(Eds) Current
Protocols in Molecular Biology, John Wiley, New York (1987).
Fifteen .mu.g of the total cellular DNA or 10 .mu.l out of the 100
.mu.l of HIRT supernatant were digested, run on a 1.0% agarose gel,
transferred to Nytran.TM. (Schleicher and Schuell, N.Y.), using a
vacublot apparatus (LKB) and hybridized with multiprimed
.sup.32P-luciferase probe (the HindIII-BamHI fragment of pRSVL).
Following hybridization overnight, the final wash of the membrane
was with 0.2.times.SSC containing 0.5% SDS at 68.degree. C. Kodak
XAR5 film was exposed to the membrane for 45 hours at -70.degree.
C.
[0234] FIG. 4 is an autoradiogram of a Southern blot having a
sample pattern as follows:
[0235] Lane 1: 0.05 ng of undigested pRSVL plasmid
[0236] Lane 2: 0.05 ng of BamH1 digested pRSVL
[0237] Lane 3: Blank
[0238] Lane 4: BamH1 digest of HIRT supernatant from control
muscle
[0239] Lane 5: BamH1 digest of cellular DNA from control,
uninjected muscle
[0240] Lanes 6,7:BamH1 digest of HIRT supernatant from two
different pools of pRSVL injected muscles
[0241] Lanes 8,9:BamH1 digest of cellular DNA from two different
pools of pRSVL injected muscle
[0242] Lane 10: Cellular DNA (same as Lane 9) digested with BamH1
and Dpn1
[0243] Lane 11: Cellular DNA (Same as in Lane 9) digested with
BamH1 and Mbo1
[0244] Lane 12: Cellular DNA digested with BgIII
[0245] Lane 13: HIRT supernatant digested with BgIII (Size markers
(X/HindIII) are shown at the left).
[0246] Southern blot analysis of muscle DNA indicates that the
foreign pRSVL DNA is present within the muscle tissue for at least
30 days (FIG. 4, lanes 6-9) and is similar to the levels of DNA
present in muscle two and 15 days following injection. In muscle
DNA digested with BamH1 (which cuts pRSVL once; FIG. 4, lanes 6-9),
the presence of a 5.6 kb band that corresponds to linearized pRSVL
(FIG. 4, lane 2) suggest that the DNA is present either in a
circular, extrachromosomal form or in large tandem repeats of the
plasmid integrated into chromosome. In muscle DNA digested with
BgIII (which does not cut pRSVL), the presence of a band smaller
than 10 kb (FIG. 4, lanes 12 and 13) and at the same size as the
open, circular form of the plasmid pRSVL (FIG. 4, lane 1) implies
that the DNA is present extrachromosomally in an open, circular
form. The appearance of the pRSVL DNA in HIRT supernatants (FIG. 4,
lanes 6, 7, and 13) and in bacteria rendered ampicillin-resistant
following transformation with HIRT supernatants also suggest that
the DNA is present unintegrated. Although the majority of the
exogenous DNA appears to be extrachromosomal, low levels of
chromosomal integration cannot be definitively excluded.
Overexposure of the blobs did not reveal smears of hybridizing DNA
larger than the 10 kb that would represent plasmid DNA integrated
at random sites. The sensitivity of the pRSVL DNA is muscle to DPNI
digestion (FIG. 4, lane 10) and its resistance to MboI digestion
(FIG. 4, lane 11), suggests that the DNA has not replicated within
the muscle cells.
EXAMPLE 15
In Vivo Expression of Pure DNA Implanted Directly into the Muscle
of Mice
[0247] pRSVL DNA was precipitated in ethanol and dried. The pellet
was picked up with fine forceps and deposited into various muscle
groups as described in the preceding examples. Five days later the
muscle was analyzed for luciferase activity as described in Example
13. The DNA was efficiently expressed in different muscle groups as
follows:
2 Implant: Luciferase Activity (Light Units, LU) 25 .mu.g pRSVL DNA
Control Biceps Calf Quadriceps 428 46420 27577 159080 453 53585
34291 35512 1171 106865 53397 105176 499 40481
EXAMPLE 16
Direct Gene Delivery into Lung: Intratracheal Injection of DNA,
DNA/CL Complexes or Pure Protein
[0248] The DNA luciferase vector (pRSVL), complexed with
Lipofectin.TM., was injected intratracheally into rats either in
20% sucrose (2 rats) or in 5% sucrose (6 rats). Two days following
the injection, the rat lungs were divided into 7 sections: LUL,
LLL, RUL, RML, RLL, AL, (defined as follows) and Trachea. The rat
lung differs from that of the human in having one large left lung
off the left main bronchus. The left lung for this study was cut in
half into a left upper part (LUL) and left lower part (LLL). The
right lung contains 4 lobes: right cranial lobe (RUL), right middle
lobe (RML), right lower lobe (RLL), and an accessory lobe (AL).
Extracts were prepared by mincing these lung parts into separate
1.5 ml microtubes containing 200 .mu.l of a lysis solution (20 mM
Tris, pH 7.4, 2 mM MgCl.sub.2 and 0.1% Triton X), and grinding the
lung with a plastic pestle. (Kontes) for one minute. In order to
ensure complete disruption of the lung cells, the lung tissue was
then placed under 600 psi of N.sub.2 in a Parr bomb at 4.degree. C.
for 15 minutes before releasing the pressure. Luciferase assays
were done on 87.5 .mu.l of lung extract out of a total volume of
about 350 .mu.l.
3 Injection RUL RLL LUL LML LLL AL Trachea Mock 22.6 22.4 21.9 21.3
20.1 19.8 -- 25 .mu.g DNA alone 21.2 21.5 21.8 21.6 21.9 21.2 -- 25
.mu.g DNA alone 21.7 21.4 21.3 -- 22.2 21.5 -- 250 .mu.g DNA alone
21.7 23.2 21.9 28.5 22.6 22.0 21.3 250 .mu.g DNA alone 22.9 22.5
33.3 23.0 25.4 24.3 21.5 250 .mu.g DNA alone 21.8 21.5 21.8 20.4
20.7 20.8 20.7 25 .mu.g DNA/CL 20.8 22.2 19.6 22.3 22.3 22.0 -- 25
.mu.g DNA/CL 22.9 22.0 22.7 21.7 22.8 -- 22.18 25 .mu.g DNA/CL 22.2
23.8 22.1 23.9 22.8 -- 21.6 25 .mu.g DNA/CL 20.9 20.9 20.9 20.6
20.3 -- 19.3 25 .mu.g DNA/CL 19.8 20.0 20.3 20.2 20.1 20.3 20.1 25
.mu.g DNA/CL 20.5 20.5 19.8 19.5 19.9 19.9 19.8 Luc Protein 105.3
77.1 98.7 80.0 86.3 89.6 178.9 3 .times. 10.sup.4 l.u. Blank
22.5
[0249] Mock: Values are those for an animal that received 25 .mu.g
of DNA in 0.3 ml
[0250] 20% sucrose into the esophagus. (A sample containing only
water yields 22.5 l.u.)
[0251] 25 .mu.g DNA alone: represent separate animals that received
intratracheal injections of 25 .mu.g of pPGKLuc in 0.3 ml 20%
sucrose.
[0252] 25 .mu.g DNA/CL: represent separate animals that received
intratracheal injections of 25 Mg of pPGKLuc complexed with
Lipofectin.TM. in 0.3 ml 5% sucrose.
[0253] The above animals were sacrificed and lung extracts prepared
2 days after injection.
[0254] Luc Protein 10.sup.4 l.u.: represents an animal that
received the equivalent of 30,000 light units (l.u.) of purified
firefly luciferase (Sigma), and then was immediately
sacrificed.
[0255] The luciferase activity in the 25 pg DNA alone and the 25
.mu.g DNA/CL groups of animals were not greater than that in the
mock animal; however, in the 250 .mu.g DNA alone animals, three
lung sections showed small but reliably elevated l.u. activity
above control lung or blanks (Bold, underlined). Duplicate assays
on the same extract confirmed the result. Experience with the LKB
.sup.125I luminometer indicates that these values, although just
above background, indicate real luciferase activity.
EXAMPLE 17
Luciferase Activity in Mouse Liver Directly injected with DNA
Formulations
[0256] The DNA luciferase expression vector pPGKLuc was injected
intrahepatically (1H) into the lower part of the left liver lobe in
mice. The pPGKLuc DNA was either injected by itself (450 Mg DNA in
1.0 ml 20% sucrose) or complexed with Lipofectin.TM. (50 .mu.g
DNA+150 .mu.g Lipofectin.TM. in 1.0 ml 5% sucrose). Three days
following injection, the left liver lobe was divided into two
sections (a lower part where the lobe was injected and an upper
part of the lobe distant from the injection site) and assayed for
luciferase activity as described in the preceding examples.
4 Mice Intrahepatic Luciferase Activity (Light Units, LU) Liver
Injection Lower Upper Blank (20.2 LU) Control: 20% Sucrose Only
20.8 23.8 50 .mu.g pPGRLuc + Lipofectin 35.4 23.1 50 .mu.g pPGKLuc
+ Lipofectin 38.1 21.4 50 .mu.g pPGKLuc + Lipofectin 22.1 22.7 450
.mu.g pPGKLuc 43.7 29.2 450 .mu.g pPGKLuc 78.8 21.7 450 .mu.g
pPGKLuc 21.7 20.8
[0257] Two of the three animals-that received the pure pPGKLuc
injections and two of the three animals that received pPGKLuc
+Lipofectin.TM. injections had luciferase activity significantly
above background (bold, underlined). The lower part of the liver
lobe, which was directly injected, had larger amounts of luciferase
activity than the upper part, which was distant from the injection
site. Similar results have been obtained using pRSVCAT DNA
expression vector and CAT assays. Luciferase activity was not
detected three days after similar preparations of pPGKLuc (+ and -
Lipofectin.TM.) were injected into the portal circulation of
rats.
EXAMPLE 18
Expression of Growth Hormone Gene Injected into Liver and
Muscle
[0258] Mice were injected with the pXGH5 (metallothionein
promoter-growth hormone fusion gene)(Selden Richard et al., Molec.
Cell Biol. 6:3173-3179 (1986)) in both liver and muscle. The mice
were placed on 76 mM zinc sulfate water. Later the animals were
bled and the serum analyzed for growth hormone using the Nichols GH
Kit.
[0259] A. Two mice were injected with 20 .mu.g of pXGH5 gene
complexed with 60 .mu.g/ml of Lipofectin in 5% sucrose. One ml of
this solution was injected into the liver and the ventral and
dorsal abdominal muscles were injected with 0.1 ml in 7 sites two
times. Two days later, the animals were bled. The serum of one
animal remained at background level, while that of the other
contained 0.75 ng/ml growth hormone.
[0260] B. Three mice were injected with 0.1 ml of 1 mg/ml of pXGH5
in 5% sucrose, 2.times.in the quadriceps, 1.times.in the hamstring
muscle, 1.times.in pectoralis muscle, and 1.times.in trapezoid
muscles on two separate days. The results were as follows:
5 Animal No. Growth Hormone(ng/ml): Day 1 Day 2 1 0.6 0.6 2 0.8 1.0
3 0.95 0.8 Background: 0.5 ng/ml
EXAMPLE 19
Antibody Production in Mice Directly Injected with a Gene for an
Immunizing Peptide
[0261] Mice were injected with a quantity of 20 .mu.g of a plasmid
construct consisting of the gp-120 gene, driven by a
cytomegalovirus (CMV) promotor. The DNA was injected into the
quadriceps muscle of mice according to the methods described in
Example 11. Mouse 5 (FIG. 5A) was injected in the quadriceps muscle
with 20 .mu.g of plasmid DNA in isotonic sucrose. Mouse 2 (FIG. 5B)
was injected with sucrose solution alone. Blood samples were
obtained prior to the injection (Day 0) at the times indicated on
FIG. 5, up to more than 40 days post injection. The serum from each
sample was serially diluted and assayed in a standard ELISA
technique assay for the detection of antibody, using recombinant
gp-120 protein made in yeast as the antigen. Both IgG and IgM
antibodies were detected. The study indicates that the gene reyains
its signal sequence, and the protein is efficiently excreted from
cells.
EXAMPLE 20
Antibody Production in Mice Injected with Cells Transfected with a
Gene for an Immunizing Peptide
[0262] The cell line BALB/C C1.7 (TIB 80) was obtained from the
American Type Tissue Culture Collection. These cells were
transfected with the gp-120 gene construct described in Example 19.
To 0.75 ml OptiMEM.TM. (Gibco. Inc.) were added 6.1 .mu.g of DNA.
The quantity of 30 .mu.g of cationic liposomes (containing DOTMA
and cholesterol in a 70:30 molar ratio) were added to another 0.75
ml OptiMEM.TM.. The mixtures were combined and 1.5 ml of
OptiMEM.TM. containing 20% (v/v) fetal bovine calf serum was added.
This solution was poured into a 60 mm plastic petri dish containing
80% confluent cells (approximately one million total cells per
plate). At 3.2 hours after lipofection, the cells were detached
from the plate with trypsin and EDTA treatment, washed with
OptiMEM.TM. and resuspended in 0.1 ml OptiMEM.TM. with 10% fetal
calf serum. These cells were injected (IP) into mice. Mouse 12
(FIG. 6A) was injected with the transfected cells. Mouse 11 (FIG.
6B) received an identical number of untransfected cells. Blood
samples were obtained prior to the injection (Day 0) and at the
times indicated in FIGS. 6A and 6B. The serum samples were
processed as in the preceding example. Both IgG and IgM antibodies
were detected as indicated in FIGS. 6A and B.
EXAMPLE 21
Use of Uncapped 5' Sequences to Direct Translation of DNA
Transfected into Cells In Vitro
[0263] Two different DNA templates were constructed, both of which
code for the synthesis of RNA that express the E. coli.
.beta.-galactosidase reporter gene. A Lac-Z gene that contains the
Kozak consensus sequence was inserted in place of the luciferase
coding sequences of the p.beta.GLuc.beta.GA.sub.n template to
generate the p.beta.GLacZ.beta.GA.sub.n template. The
pEMCLacZ.beta.GA.sub.n template was made by replacing the 5'
.beta.-globin untranslated sequences of p.beta.GLacZ.beta.GA.sub.n
with the 588 bp EcoRl/Ncol fragment from the encephalomyocarditis
virus (EMCV) (pE5LVPO in Parks, G. et al., J. Virology 60:376-384
(1986). These EMC 5' untranslated sequences had previously been
shown to be Able to initiate efficient translation in vitro in
reticulocytes lysates. We demonstrated that these sequences can
also direct efficient translation when transfected into fibroblasts
in culture. The percentage of blue cells was slightly greater in
cells transfected with the uncapped EMCLacZ.beta.GA.sub.n RNA than
in cells transfected with the capped pEMCLacZ.beta.GA.sub.n RNA.
Transfection with either uncapped or capped pEMCLacZ.beta.GA.sub.n
RNA yielded a greater number of positive .beta.-galactosidase cells
than transfection with capped .beta.GLacZ.beta.DGA.sub.n RNA. It
has recently been shown that this EMC 5' untranslated sequence, as
a component of vaccinia-T7 polymerase vectors, can increase
translation of an uncapped mRNA 4 to 7-fold (Elroy-Stein, 0. et
al., Proc. Natl. Acad. Sci. USA 86:6126-6130 (1989). These EMC
sequences thus have the ability to direct efficient translation
from uncapped messengers.
EXAMPLE 22
T7 Polymerase Transcription in Transfected Cell Cultures
[0264] An SV40-T7 polymerase plasmid containing T7 polymerase
protein expressed off the SV40 promotor (Dunn, J. et al., Gene 68:
259 (1988)) was co-lipofected with the pEMCLacZ.beta.GAn template
DNA into 3T3 fibroblasts in culture to demonstrate that T7
polymerase transcription can occur via plasmids. Two different
SV40-T7 polymerase expression vectors were used:
[0265] (a) pSV-G1-A: pAR3126-SV40 promotor driving expression of T7
polymerase protein which is directed to the cytoplasm.
[0266] (b) pSVNU-G1-A: pAR3132-SV40 promotor driving expression of
T7 polymerase protein which is directed to the cytoplasm.
[0267] Each of these two plasmids were co-lipofected with
pEMCLacZ.beta.GAn at 1:3 and 3:1 ratios into 60 mm plates of 3T3
cells. The number of blue .beta.-galactosidase cells were counted
and scored as indicated below.
6 .beta.-gal Ratio:template/ Co-Lipofectant: template polymerase
vector pSV-G1-A pSVNU-G1-A .beta.GLacZ.beta.3GAn 3:1 0 1 1:3 0 1
EMCLacZ.beta.3GAn 3:1 74 70 1:3 45 15
EXAMPLE 23
Expression of Luciferase in Brain Following Directed Injection of
Messenger RNA
[0268] Two adult mice and one newborn mouse were injected with the
.beta.gLuc.beta.gA.sub.n mRNA containing the 5' cap and prepared
according to Example 13. In the adult mice, injections were from a
stock solution of mRNA at 3.6 .mu.g/.mu.l in 20% sucrose; injection
volumes were 5 .mu.1,2 injections into each of the bilateral
parietal cortex, 4 injections per mouse. Tissue was assayed at 18
hours post injection, according to Example 13 using 200 .mu.l of
brain homogenate, disrupted in a Parr bomb, and 87.5 .mu.l was
taken for assay.
[0269] The results are as follows:
7 Hemisphere: Treatment Animal I.D. Left Right Sham Injection AMra
649 629 .beta.gLuc.beta.gA.sub.n AMrb 1,734 1,911
[0270] The newborn mouse was injected with 1 .mu.l
.beta.gLuc.beta.gAn
[0271] (3.6 .mu.g/.mu.l; 20% sucrose) into the bilateral forebrain
and tissues were similarly processed and analyzed.
8 Hemisphere: Treatment Animal I.D. Left Right .beta.gLuc.beta.gAn
NRr 1,569 963
EXAMPLE 24
Functional Expression of Dystrophin in Dystrophic Mouse Muscle In
Vivo
[0272] A plasmid containing the dystrophin gene under control of
the Rous Sarcoma virus promoter was prepared from the Xp21 plasmid
containing the complete dystrophin coding region and the SV40 poly.
A segment, which was cloned by Kunkel and colleagues. (Brumeister
M., Monaco A P, Gillard E F, van Ommen G J, Affara N A,
Ferguson-Smith M A, Kunkel L M, Lehrach H. A 10-megabase physical
map of human Xp21, including the Duchenne muscular dystrophy gene.
Genomics 1988 Apr 2 (3):189-202; Hoffman, E P and Kunkel, L M
Dystrophin abnormalities of Duchenne's/Becher Muscular Dystrophy.
Neuron Vol. 2, 1019-1029 (1989); Koenig M., Monaco A P, Kunkel L M.
The complete sequence of dystrophin predicts a rod-shaped
cyto-skeletal protein. Cell 1988 Apr 22, 53 (2):219-26) 200 .mu.g
of the plasmid in 100 ul of phosphate buffered saline was injected
into the quadriceps the mutant mouse strain lacking the dystrophin
gene product (MDX mouse; Jackson labs). Expression of functional
dystrophin was monitored 7 days post injection by
immuno-histochemistry according to the procedures described by
Watkins et al. and using the same anti-dystrophin antibody (anti-60
kd antibody with a fluorescent secondary antibody) obtained from
Kunkel. Functional expression of the dystrophin gene product in the
dystrophic mice was detected by comparing the pattern of
fluorescence observed in cross-sections of quadriceps muscle from
injected animals, with the fluorescence pattern observed in normal
animals. (Watkins S. C., Hoffman E. P., Slayter H. S., Kinkel L.
M., Immunoelectron microscopic localization of dystrophin in
myofibres. Nature 1988, June 30; 333 (6176:863-6). Normal
dystrophin expression is localized underneath the plasma membrane
of the muscle fiber, so that a cross section of the quadriceps
muscle give a fluorescence pattern encircling the cell. In addition
dystrophin expression was quantitated by Western blot analysis
using the affinity purified anti-60 kd antibody.
EXAMPLE 25
Administration of the Correcting Dystrophin Gene Directly into the
Muscle of Patients with Duchenne's Muscular Dystrophy
[0273] Patients with muscular dystrophy are given multiple 200
.mu.g injections of plasmid containing the functional dystrophin
gene (see previous example) in 100 .mu.l of phosphate buffered
saline. While under light anesthesia the patients are injected at 5
cm intervals into the entire skeletal muscle mass directly through
the skin without surgery. Patient recovery evaluated by monitoring
twitch tension and maximum voluntary contraction. In addition,
biopsies of 300-500 muscle cells from an injected area are taken
for histological examination, observing muscle structure and
biochemical analysis of the presence of dystrophin, which is absent
in patients with Duchenne's muscular dystrophy. Respiratory
muscles, including the intercostal muscles which move the rib cage
and the diaphragm, are particularly important impaired muscle
groups in patients with muscular dystrophy. The intercostals can be
reached by injection through the skin as can the other skeletal
muscle groups. The diaphragm can be accessed by a surgical
procedure to expose the muscle to direct injection of plasmid
DNA.
[0274] There will be various modifications, improvements, and
applications of the disclosed invention that will be apparent to
those of skill in the art, and the present application is intended
to cover such embodiments. Although the present invention has been
described in the context of certain preferred embodiments, it is
intended that the full scope of these be measured by reference to
the scope of the following claims.
* * * * *