U.S. patent number 6,534,062 [Application Number 09/820,484] was granted by the patent office on 2003-03-18 for methods for increasing a cytotoxic t lymphocyte response in vivo.
This patent grant is currently assigned to The Regents of the University of California, The United States of America as represented by the Department of Veterans Affairs. Invention is credited to Hearn Jay Cho, Anthony A. Horner, Eyal Raz, Douglas Richman.
United States Patent |
6,534,062 |
Raz , et al. |
March 18, 2003 |
**Please see images for:
( Certificate of Correction ) ** |
Methods for increasing a cytotoxic T lymphocyte response in
vivo
Abstract
The invention provides methods for T helper-independent
activation of an antigen-specific cytotoxic T lymphocyte response
in an individual. The methods generally involve administering to an
individual an immunostimulatory nucleic acid molecule in an amount
effective to increase an antigen-specific CTL response in the
individual. The invention further provides methods for increasing
chemokine secretion, which can block HIV infection.
Inventors: |
Raz; Eyal (Del Mar, CA),
Cho; Hearn Jay (New York, NY), Richman; Douglas (La
Jolla, CA), Horner; Anthony A. (San Diego, CA) |
Assignee: |
The Regents of the University of
California (Oakland, CA)
The United States of America as represented by the Department of
Veterans Affairs (Washington, DC)
|
Family
ID: |
27393066 |
Appl.
No.: |
09/820,484 |
Filed: |
March 28, 2001 |
Current U.S.
Class: |
424/193.1;
536/24.1; 536/23.1 |
Current CPC
Class: |
A61K
39/0011 (20130101); A61K 39/39 (20130101); A61K
39/21 (20130101); A61K 39/12 (20130101); A61K
39/385 (20130101); A61K 2039/55 (20130101); A61K
2039/543 (20130101); C12Q 1/703 (20130101); A61K
2039/585 (20130101); A61K 2039/545 (20130101); A61K
2039/6025 (20130101); A61K 2039/57 (20130101); C12N
2740/16134 (20130101); A61K 2039/54 (20130101); A61K
2039/55561 (20130101); A61K 2039/53 (20130101) |
Current International
Class: |
A61K
39/385 (20060101); A61K 39/21 (20060101); A61K
39/39 (20060101); A61K 39/00 (20060101); C12Q
1/70 (20060101); A61K 039/385 (); C07H
021/04 () |
Field of
Search: |
;536/23.1,24.1
;424/193.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
WO 98/16247 |
|
Apr 1998 |
|
WO |
|
WO 00/20039 |
|
Apr 2000 |
|
WO |
|
Other References
Alkhatib et al. (1996) "CC CKR5: A RANTES, MIP-1 .alpha.,
MIP-1.beta. receptor as a Fusion Cofactor for Macrophage-Tropic
HIV-1." Science, vol. 272:1955-1958. .
Bauer et al. (1999) "DNA activates human immune cells through a CpG
sequence-dependent manner." Immunology, vol. 97:699-705. .
Bennett et al. (1998) "Help for cytotoxic-T-cell responses is
mediated by CD40 signalling." Nature, vol. 393:478-480. .
Carson et al. (1997) "Oligonucleotide Adjuvants for T Helper 1
(Th1)-specific Vaccination." J. Exp. Med., vol. 186 (10):
1621-1622. .
Cho et al. (2000) "Immunostimulatory DNA-based vaccines induce
cytotoxic lymphocyte activity by a T-helper cell-independent
mechanism." Nature Biotechnology, vol. 18:509-514. .
Choe et al. (1996) "The .beta.-Chemokine receptors CCR3 and CCR5
Facilitate Infection by Primary HIV-1 Isolates." Cell, vol.
85:1135-1148. .
Chu et al. (2000) "DNA-PKcs is Required for Activation of Innate
Immunity by Immunostimulatory DNA." Cell, vol. 103:909-918. .
Cocchi et al. (1995) "Identification of RANTES, MIP-1.alpha., and
MIP-1.beta. as the Major HIV-Suppressive Factors Produced by CD8+ T
cells." Science, vol. 270:1811-1815. .
Corr et al. (1996) "Gene Vaccination with Naked Plasmid DNA:
Mechanism of CTL Priming." J. Exp. Med., vol. 184:1555-1560. .
Deng et al. (1996) "Identification of a major co-receptor for
primary isolates of HIV-1." Nature, vol. 381:661-666. .
Dragic et al. (1996) "HIV-1 entry into CD4+ cells is mediated by
the chemokine receptor CC-CKR-5." Nature, vol. 381:667-673. .
Grewal et al. (1996) "The Role of CD40 Ligand in Costimulation and
T-cell Activation." Immunological Reviews, No. 153:85-106. .
Harding et al. (1993) "CD28-B7 Interactions Allow the Induction of
CD8+ Cytotoxic T Lymphocytes in the Absence of Exogenous Help." J.
Exp. Med., vol. 177:1791-1796. .
Hemmi et al. (2000) "A Toll-like receptor recognizes bacterial
DNA." Nature, vol. 408:740-745. .
Horner et al. (1998) "Immunostimulatory DNA is a Potent Mucosal
Adjuvant." Cellular Immunology, vol. 190:77-82. .
Keene et al. (1982) "Helper Activity is Required for the in vivo
generation of Cytotoxic T Lymphocytes." J. Exp. Med., vol.
155:768-782. .
Moss et al. (2000) "In vitro immune function after vaccination with
an inactivated, gp120-depleted HIV-1 antigen with immunostimulatory
oligodeoxynucleotides." Vaccine, vol. 18:1081-1087. .
Ridge et al. (1998) "A conditioned dendritic cell can be a temporal
bridge between a CD4+ T-helper and a T-killer cell." Nature, vol.
393:474-478. .
Schoenberger et al. (1998) "T-cell help for cytotoxic T lymphocytes
is mediated by CD40-CD40L interactions." Nature, vol. 393:480-483.
.
Sigal et al. (1998) "The Role of B7-1 and B7-2 Costimulation for
the Generation of CTL Responses in vivo." The Journal of
Immunology, vol. 161:2740-2745. .
Sparwasser et al. (1998) "Bacterial DNA and immunostimulatory CpG
oligonucleotides trigger maturation and activation of murine
dendritic cells." Eur. J. Immunol., vol. 28:2045-2054. .
Tokunaga et al. (1984) "Antitumor Activity of Deoxyribonucleic Acid
Fraction From Mycobactrium bovis BCG. I. Isolation, Physicochemical
Characterization, and Antitumor Activity." JNGI, vol.
72(4):955-962. .
Yamamoto et al. (1992) "DNA from Bacteria, but Not from
Vertebrates, induces Interferons, Activates Natural Killer Cells
and Inhibits Tumor Growth." Microbiol. Immunol., vol.
36(9):983-997..
|
Primary Examiner: Ketter; James
Assistant Examiner: Qian; Celine
Attorney, Agent or Firm: Borden; Paula A. Bozicevic, Field
& Francis, LLP
Government Interests
GOVERNMENT RIGHTS
The United States Government may have certain rights in this
application pursuant to National Institutes of Health Grant Nos.
AI40682 and A147078.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Patent
Application Ser. No. 60/192,537, filed Mar. 28, 2000; U.S.
Provisional Patent Application Ser. No. 60/203,567, filed May 11,
2000; and U.S. Provisional Patent Application Ser. No. 60/215,895,
filed Jul. 5, 2000, which applications are each incorporated herein
by reference in their entirety.
Claims
What is claimed is:
1. A method of increasing antigen-specific T lymphocyte activity in
a CD4+ T cell-deficient individual, comprising administering a
formulation comprising an immunostimulatory nucleic acid molecule
and an antigen in an amount effective to increase antigen-specific
CTL activity, wherein the immunostimulatory nucleic acid is
covalently linked to the antigen.
2. The method of claim 1, wherein the immunostimulatory nucleic
acid comprises the sequence 5' C-G 3'.
3. The method of claim 1, wherein the antigen is associated with an
intracellular pathogen.
4. The method of claim 1, wherein the antigen is a tumor-associated
antigen.
5. The method of claim 1, wherein the immunostimulatory nucleic
acid molecule comprises a nucleotide sequence selected from the
group consisting of
5'-purine-purine-cytosine-guanine-pyrimidine-pyrimidine-3';
5'-purine-TCG-pyrimidine-pyrimidine-3'; and 5'-(TGC).sub.n -3',
where n.gtoreq.1.
6. The method of claim 1, wherein the individual has a reduced
number of CD4.sup.+ T lymphocytes due to a primary
immunodeficiency.
7. The method of claim 1, wherein the individual has a reduced
number of CD4.sup.+ T lymphocytes due to an acquired
immunodeficiency.
8. The method of claim 7, wherein the acquired immunodeficiency is
a temporary immunodeficiency due to a treatment selected from the
group consisting of radiation therapy to treat a cancer,
chemotherapy to treat a cancer, immunosuppression following bone
marrow transplantation, immunosuppression caused by treatment for
an autoimmune disease, and immunosuppression following organ
transplantation.
9. The method of claim 7, wherein the acquired immunodeficiency is
acquired immunodeficiency syndrome.
10. The method of claim 1, wherein said immunostimulatory nucleic
acid molecule is administered to a mucosal tissue.
11. The method of claim 1, wherein said immunostimulatory nucleic
acid molecule is administered systemically.
Description
FIELD OF THE INVENTION
This invention relates to methods of modulating an immune response,
and in particular to methods of increasing an antigen-specific
cytotoxic T lymphocyte response.
BACKGROUND OF THE INVENTION
Immunostimulatory nucleic acid molecules were initially discovered
in the mycobacterial genome as DNA sequences that selectively
enhance NK cell activity (Yamamoto, et al. (1992) Microbiol.
Immunol. 36:983-997). Uptake of mycobacterial DNA or has been shown
to activate cells of the innate immune system, such as NK cells and
macrophages and stimulating a type-1 like response (Roman, et al.
(1997) Nature Med. 3:849-854). Further, administration of
immunostimulatory nucleic acid molecules has been shown to induce B
cell proliferation (Messina, et al. (1991) J. Immunol.
147:1759-1764), stimulate production of cytokines, such as
interferons (IFNs), IL-12, IL-18 and TNF-.alpha. (Sparwasser, et
al. (1998) Eur. J. Immunol. 28:2045-2054; Sparwasser, et al. (1997)
Eur. J. Immunol. 27:1671-1679; Stacey, et al. (1996) J. Immunol.
157:2116-2122) and up-regulate co-stimulatory receptors
(Martin-Orozco, et al. (1999) Int. Immun. 11:111-118; Sparwasser,
et al. (1998) Eur. J. Immunol. 28:2045-2054) by these cells.
Cytotoxic T Lymphocytes (CTL) are critical effector cells in the
control of cells infected with intracellular pathogens and in the
control of MHC class I+ tumors. Induction of CTL is a primary goal
of many vaccine strategies. Accumulating evidence indicates that
one of the pathways of CTL priming in vivo is through
"cross-priming," which involves the uptake and re-presentation of
soluble, exogenous antigens by bone marrow-derived
antigen-presenting cells (APCs), e.g., dendritic cells. Depending
on the activation state of the "cross-presenting" APC, responding T
cells can either be activated or tolerized. The nature of the
specific requirements for these disparate outcomes is currently a
topic of intense interest, as elucidation of such would aid in the
design of vaccines as well as in the modulation of anti-tumor CTL
responses. Current models of cross-priming consist of two steps; a
"licensing" interaction between antigen presenting cells (APC) and
helper T cells (T.sub.h), followed by an activating interaction
between "licensed" APC and cytotoxic T lymphocytes (CTL). Thus, in
current models, there is a requirement for T.sub.h cells in
cross-priming of CTL.
Immunodeficiency can arise from a variety of causes, including
primary immunodeficiencies, e.g., due to a heritable defect; and
acquired immunodeficiencies, e.g., due to cancer chemotherapy, or
due to infection with a pathogen, e.g., human immunodeficiency
virus. Immunodeficient individuals are more vulnerable to
infectious diseases than individuals with healthy immune systems.
Antibiotics can control bacterial infections, but long-term
treatment with antibiotics is not without risk of adverse side
effects. Control of intracellular pathogens, including viruses,
bacteria, and protozoans, poses a greater challenge for treatment.
Immunodeficient individuals may also be more vulnerable to growth
of cancer cells than individuals with healthy immune systems.
Treatment of these individuals with conventional anti-cancer
therapeutic agents is not always feasible.
The current methodologies for inducing a CTL response include
vaccines which use attenuated viruses or DNA vaccines. There is a
need in the art for more effective ways of increasing an
antigen-specific CTL response in an individual. Furthermore, there
is a need in the art for alternative methods of enhancing immune
functions in immunodeficient individuals. The present invention
addresses these needs by providing methods for increasing cytotoxic
T lymphocyte (CTL) activity. The methods are useful for increasing
an antigen-specific CTL response in an individual to any soluble
antigen. The methods are also useful for increasing an
antigen-specific CTL response in CD4.sup.+ -deficient individuals
and individuals at risk for becoming CD4.sup.+ deficient.
SUMMARY OF THE INVENTION
The invention provides methods for T helper-independent activation
of an antigen-specific cytotoxic T lymphocyte response in an
individual. The methods generally involve administering to an
individual an immunostimulatory nucleic acid molecule in an amount
effective to increase an antigen-specific CTL response in the
individual. The invention further provides methods for increasing
chemokine secretion, which can block HIV infection.
The methods are useful for generating both a CTL response and a
humoral response to a soluble exogenous antigen. Thus, an
immunostimulatory nucleic acid molecule, when administered together
with a soluble, exogenous antigen, results in cross-priming of
CTLs. Therefore, the methods are useful in generating an immune
response, particularly a CTL response, to a cell infected with an
intracellular pathogen, or to a tumor cell expressing a
tumor-specific or tumor-associated antigen.
The methods are also useful in treating individuals with a reduced
number of functional CD4.sup.+ T cells ("CD4.sup.+ -deficient
individuals" or "CD4.sup.+ -low individuals") compared to normal
individuals, e.g. individuals affected by an acquired or primary
immunodeficiency, as well as those at risk for becoming
immunodeficient.
The immunostimulatory nucleic acid molecules may be administered in
a formulation alone, or together with an antigen, e.g., admixed or
linked or conjugated to an antigen or antigenic epitope. In many
embodiments, the antigen is a soluble, exogenous antigen. The
methods are useful in stimulating, or increasing antigen-specific
CTL activity to any of a variety of target antigens, e.g., an
antigen expressed in a cell, or an antigen expressed on the surface
of a cell or cell population. In some embodiments, methods are
provided for increasing CTL activity toward pathogen-infected
cells. In other embodiments, methods are provided for increasing
CTL activity toward a tumor cell.
The invention further provides methods for increasing
tumor-specific immunity in an individual. The methods generally
involve administering to an individual an immunostimulatory nucleic
acid molecule in an amount effective to increase tumor-specific
immunity in an individual. The methods are useful to treat cancer,
e.g., to inhibit the growth of cancer cells. The methods are also
useful as a preventive measure, e.g., to inhibit the probability
that cancerous cell growth will occur, or that a previously treated
cancer will recur. The methods are particularly useful for
decreasing a tumor load in a CD4.sup.+ T-cell deficient individual,
and in individuals at risk for becoming CD4.sup.+ deficient.
The invention further provides methods of immunizing against and/or
treating an infectious disease in an individual. The methods
generally involve administering to an individual an
immunostimulatory nucleic acid molecule in an amount effective to
increase antigen-specific CTL activity. The methods are
particularly useful in immunizing against and/or treating
infectious diseases due to intracellular pathogens. The methods are
also useful for treating infectious disease in a CD4.sup.+ T-cell
deficient individual, and in individuals at risk for becoming
CD4.sup.+ deficient.
The present invention further provides compositions and methods for
increasing secretion of a chemokine from a eukaryotic cell, which
in turn inhibits infection of a cell by pathogens that establish
infection in a host, or cause disease by, interaction with a
chemokine receptor. The methods generally involve contacting a cell
with a composition comprising an immunostimulatory nucleic acid
molecule. Accordingly, the invention further provides methods of
reducing infection of a cell by a pathogen, comprising contacting a
cell with an immunostimulatory nucleic acid molecule such that
chemokine secretion is increased, and infection is reduced.
Chemokine secretion may be antigen specific, where both
immunostimulatory nucleic acid molecule and antigen are
administered, or antigen non-specific, where immunostimulatory
nucleic acid molecule is administered in the absence of exogenously
provided antigen.
Immunostimulatory nucleic acid molecules induce secretion of
chemokines that bind to chemokine receptors. Certain chemokine
receptors are used by pathogenic microorganisms to enter and infect
a cell. Increasing synthesis of such chemokines serves to
competitively inhibit binding of the pathogenic microorganism to
the chemokine receptor. Accordingly, in further aspects, the
present invention provides compositions and methods for increasing
secretion of a chemokine from a eukaryotic cell, which in turn
inhibits infection of a cell by pathogens that establish infection
in a host, or cause disease by, interaction with a chemokine
receptor. The methods generally involve contacting a cell with a
composition comprising an immunostimulatory nucleic acid molecule.
Accordingly, the invention further provides methods of reducing
infection of a cell by a pathogen, comprising contacting a cell
with an immunostimulatory nucleic acid molecule such that chemokine
secretion is increased, and infection is reduced. Chemokine
secretion may be antigen specific, where both immunostimulatory
nucleic acid molecule and antigen are administered, or antigen
non-specific, where immunostimulatory nucleic acid molecule is
administered in the absence of exogenously provided antigen.
These and other objects, advantages, and features of the invention
will become apparent to those persons skilled in the art upon
reading the details of the invention as more fully described
below.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a graph depicting the effect of vaccination with
protein-ISS conjugates on antigen-specific CTL activity. Animals
were injected intradermally with protein-ISS conjugate (open
squares), using hen egg ovalbumin (OVA) as a model antigen; OVA+ISS
(open diamonds); pACB-OVA (closed circles); OVA alone (closed
triangles); protein-mutated ISS conjugate (open diamonds); or
target control (open squares). Open circles indicate no
treatment.
FIGS. 2A-C are graphs depicting the effects of vaccination with
protein-ISS conjugates on the Th1 immune response. Total
splenocytes were restimulated as described in Example 2, and
IFN.gamma. levels (FIG. 2A) were measured. IgG1 titers (FIG. 2B),
and IgG2a titers (FIG. 2C) were measured in serum.
FIGS. 3A-C are graphs depicting MHC Class-I restricted CTL
activation in CD4 -/- by protein-ISS conjugates in wild type (FIG.
3A), CD4-/- (FIG. 3B), and MHC class II-/- (FIG. 3C) mice. Mice
were injected intradermally on days zero and 14 with either
protein-ISS conjugate (squares); OVA+ISS (diamonds); or OVA alone
(circles).
FIGS. 4A-C are graphs depicting protective immunity conferred by
vaccination with protein-ISS conjugates in preventive and
therapeutic models of cancer.
FIG. 5 is a graph depicting specific lysis versus effector:target
ratio for CTL from chimeric mice made from wild-type mice and
TAP.sup.-/- bone-marrow injected with ISS+OVA (TAP.sup.-/31
.fwdarw.wt); wild-type mice with wild-type bone marrow injected
with ISS+OVA (wt.fwdarw.wt); wild-type mice injected with ISS+OVA
(wt); and wild-type mice not injected with ISS+OVA (no
treatment).
FIG. 6 is a graph depicting specific lysis versus effector:target
ratio for CTL from wild-type injected with ISS+OVA (wt);
CD40.sup.-/- mice injected with ISS+OVA; wild-type mice pre-treated
with anti-CD40 ligand and injected with ISS+OVA (wt, anti-CD40 L);
wild-type mice injected with OVA alone (OVA); and wild-type mice
not injected with ISS+OVA (no treatment).
FIG. 7 is a graph depicting specific lysis versus effector:target
ratio for CTL from wild-type injected with ISS+OVA (wt); wild-type
mice pre-treated with anti-B7-1/-2 and injected with ISS+OVA (anti
B7-1/-2); wild-type mice pre-treated with anti-B7-1/-2 and
anti-CD40 ligand antibody, and injected with ISS+OVA (anti B7-1/-2;
anti CD40 L); CD28.sup.-/- mice injected with ISS+OVA; and
CD28.sup.-/- mice pre-treated with anti-CD40 ligand antibody, and
injected with ISS+OVA (CD28.sup.-/- ; anti-CD40L).
FIG. 8 is a graph depicting specific lysis versus effector:target
ratio for CTL from wild-type injected with ISS+OVA (wt);
IL-12.sup.-/- mice injected with ISS+OVA; IL-12.sup.-/- mice
pre-treated with anti-CD40L antibody and anti-B7-1/-2 antibody,
then injected with ISS+OVA (IL-12.sup.-/- ; anti-CD40L;
anti-B7-1/-2); wild-type mice injected with OVA alone (wt, OVA
alone); and wild-type mice not injected with ISS+OVA (no
treatment).
FIG. 9 is a bar graph depicting production of MIP1.alpha. by mouse
splenocytes in response to immunization with ISS and gp120.
FIG. 10 is a bar graph depicting production of MIP1.beta. by mouse
splenocytes in response to immunization with ISS and gp120.
FIG. 11 is a bar graph depicting production of RANTES by mouse
splenocytes in response to immunization with ISS and gp120.
FIGS. 12A-D are graphs depicting antigen-specific immunoglobulin
(FIG. 12A), cytokine (FIG. 12B), and chemokine (FIGS. 12C and 12D)
responses in mice injected intradermally with ISS-based gp120
vaccines.
FIGS. 13A-E are graphs depicting systemic antigen-specific
immunoglobulin (FIG. 13A), mucosal antigen-specific immunoglobulin
(FIG. 13B), cytokine (FIG. 13C), and chemokine (FIGS. 13D and 13E)
responses in mice immunized intranasally with ISS-based gp120
vaccines.
FIGS. 14A-D are graphs depicting splenic and mucosal CTL activity
in mice immunized intradermally (FIG. 14A) or intranasally (FIG.
14B). Mucosal CTL activity from lamina propria (FIG. 14C) and
Peyer's patch (FIG. 14D) lymphocytes was determined 12 weeks after
initiation of i.n. or i.d. immunization.
FIGS. 15A-C are graphs depicting MHC Class I-restricted IFN.gamma.
(FIG. 15A) and chemokine (FIGS. 15B and 15C) responses in mice
immunized intradermally with ISS-based gp120 vaccines.
FIGS. 16A-E are graphs depicting MHC Class I-restricted cytokine
(FIGS. 16A and 16D), chemokine (FIGS. 16B, C, and D) and CTL
activity (FIG. 16E) elicited by gp120:ISS vaccination in normal
(untreated) or CD4-depleted (treated with anti-CD4 Ab) mice.
DETAILED DESCRIPTION OF THE INVENTION
The immune system can react to the presence of a foreign antigen by
generating antigen-specific CD4.sup.+ (helper) T cells and
CD8.sup.+ (cytotoxic) T cells. CD4.sup.+ T cells are sometimes
classified as Th1 or Th2, depending on the cytokine profile
produced. The present invention relates to the observation that an
immunostimulatory nucleic acid molecule can stimulate an
antigen-specific cytotoxic T lymphocyte (CTL) response even in the
absence of CD4.sup.+ T helper cells. This observation is counter to
the accepted model of a requirement for CTL activation. Current
models posit that an antigen-presenting cell (APC), must have an
initial "licensing" interaction with Th cells before the Th cells
can activate CTL. Previous work describing the APC response to
immunostimulatory nucleic acid molecule stimulation (e.g.,
upregulation of cytokines and co-stimulatory molecules) suggested
that APCs deliver the stimulatory signal to T helper cells. The
present inventors have made the surprising discovery that, contrary
to this model, immunostimulatory nucleic acid molecules are capable
of increasing an antigen-specific CTL response, even in the absence
of in a CD4.sup.+ T lymphocytes. In addition, immunostimulatory
nucleic acid molecules increase chemokine secretion, which
chemokines are competitive inhibitors of HIV for binding to HIV
receptors.
Without wishing to be bound by theory, immunostimulatory nucleic
acid molecules may replace some or all of the "licensing" effects
on APCs, indicating that the Th1 phenotype and CTL activation are
independent, rather than linked. Thus, the immunostimulatory
nucleic acid molecule allows the APC to activate directly
antigen-specific CTL activity. The present inventors' observations
thus make it possible, for the first time, to use immunostimulatory
nucleic acid molecules to increase a CTL response in CD4.sup.+ T
helper cell-deficient individuals.
Accordingly, the present invention provides methods of inducing or
increasing antigen-specific CTL activity in an individual via
cross-presentation, comprising administering an immunostimulatory
nucleic acid molecule and a soluble exogenous antigen to the
individual. The methods generally involve administering to an
individual an immunostimulatory nucleic acid molecule, which may
optionally be administered with an antigen, particularly a soluble
exogenous antigen. The methods can be used to increase or induce a
CTL response to various undesired cells or cell populations, e.g.,
pathogen-infected cells, and tumor cells.
The invention further provides methods of inducing CTL activity in
CD4-deficieint individuals or to individuals with a healthy, intact
immune system, but who are at risk for becoming CD4.sup.+
deficient. The methods generally involve administering to an
individual an immunostimulatory nucleic acid molecule (which may
optionally be administered with an antigen, particularly a soluble
exogenous antigen), and are useful in increasing or inducing a CTL
response to various undesired cells or cell populations, e.g.,
pathogen-infected cells, and tumor cells.
The present invention further provides compositions and methods for
increasing chemokine secretion from a eukaryotic cell, particularly
to inhibit infection of the cell by a pathogen that establishes
infection or otherwise causes disease or symptoms of disease in a
host by interaction with a chemokine receptor. This aspect of the
invention is based on the unexpected discovery that certain
polynucleotides, termed immunostimulatory nucleic acid molecules,
can increase secretion of chemokines from cells that normally
produce chemokines. For example, increased chemokine production,
particularly of chemokines that bind HIV co-receptors, can reduce
the incidence of HIV entry into a cell. Thus, the invention further
provides methods of reducing susceptibility to infection of a
susceptible eukaryotic cell by a pathogen, as well as methods for
treating an infection by a pathogen. The methods involve
administering an immunostimulatory nucleic acid molecule to an
individual to increase secretion of a chemokine that binds to a
chemokine receptor which serves as a co-receptor for infection by a
pathogen. The secreted chemokine binds to the chemokine receptor
and reduces pathogen entry into the cell, or otherwise reduces the
undesirable effects of pathogen interaction with the cell.
Before the present invention is described, it is to be understood
that this invention is not limited to particular embodiments
described, as such may, of course, vary. It is also to be
understood that the terminology used herein is for the purpose of
describing particular embodiments only, and is not intended to be
limiting, since the scope of the present invention will be limited
only by the appended claims.
Unless defined otherwise, all technical and scientific terms used
herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this invention belongs. Although
any methods and materials similar or equivalent to those described
herein can be used in the practice or testing of the present
invention, the preferred methods and materials are now described.
All publications mentioned herein are incorporated herein by
reference to disclose and describe the methods and/or materials in
connection with which the publications are cited.
It must be noted that as used herein and in the appended claims,
the singular forms "a", "and", and "the" include plural referents
unless the context clearly dictates otherwise. Thus, for example,
reference to "an immunostimulatory nucleic acid molecule" includes
a plurality of such molecules and reference to "the tumor cell"
includes reference to one or more tumor cells and equivalents
thereof known to those skilled in the art, and so forth.
The publications discussed herein are provided solely for their
disclosure prior to the filing date of the present application.
Nothing herein is to be construed as an admission that the present
invention is not entitled to antedate such publication by virtue of
prior invention. Further, the dates of publication provided may be
different from the actual publication dates which may need to be
independently confirmed.
Definitions
The terms "oligonucleotide," "polynucleotide," and "nucleic acid
molecule", used interchangeably herein, refer to a polymeric forms
of nucleotides of any length, either ribonucleotides or
deoxyribonucleotides. Thus, this term includes, but is not limited
to, single-, double-, or multi-stranded DNA or RNA, genomic DNA,
cDNA, DNA-RNA hybrids, or a polymer comprising purine and
pyrimidine bases or other natural, chemically or biochemically
modified, non-natural, or derivatized nucleotide bases. The
backbone of the polynucleotide can comprise sugars and phosphate
groups (as may typically be found in RNA or DNA), or modified or
substituted sugar or phosphate groups. Alternatively, the backbone
of the polynucleotide can comprise a polymer of synthetic subunits
such as phosphoramidites, and/or phosphorothioates, and thus can be
an oligodeoxynucleoside phosphoramidate or a mixed
phosphoramidate-phosphodiester oligomer. Peyrottes et al. (1996)
Nucl. Acids Res. 24:1841-1848; Chaturvedi et al. (1996) Nucl. Acids
Res. 24:2318-2323. The polynucleotide may comprise one or more
L-nucleosides. A polynucleotide may comprise modified nucleotides,
such as methylated nucleotides and nucleotide analogs, uracyl,
other sugars, and linking groups such as fluororibose and thioate,
and nucleotide branches. The sequence of nucleotides may be
interrupted by non-nucleotide components. A polynucleotide may be
further modified after polymerization, such as by conjugation with
a labeling component. Other types of modifications included in this
definition are caps, substitution of one or more of the naturally
occurring nucleotides with an analog, and introduction of means for
attaching the polynucleotide to proteins, metal ions, labeling
components, other polynucleotides, or a solid support.
The terms "polypeptide," "peptide," and "protein", used
interchangeably herein, refer to a polymeric form of amino acids of
any length, which can include coded and non-coded amino acids,
chemically or biochemically modified or derivatized amino acids,
and polypeptides having modified peptide backbones. The term
includes polypeptide chains modified or derivatized in any manner,
including, but not limited to, glycosylation, formylation,
cyclization, acetylation, phosphorylation, and the like. The term
includes naturally-occurring peptides, synthetic peptides, and
peptides comprising one or more amino acid analogs. The term
includes fusion proteins, including, but not limited to, fusion
proteins with a heterologous amino acid sequence, fusions with
heterologous and homologous leader sequences, with or without
N-terminal methionine residues; immunologically tagged proteins;
and the like.
The term "tumor-associated antigen" is a term well understood in
the art, and refers to surface molecules that are differentially
expressed in tumor cells relative to non-cancerous cells of the
same cell type. As used herein, "tumor-associated antigen" includes
not only complete tumor-associated antigens, but also
epitope-comprising portions (fragments) thereof. A tumor-associated
antigen (TAA) may be one found in nature, or may be a synthetic
version of a TAA found in nature, or may be a variant of a
naturally-occurring TAA, e.g., a variant which has enhanced
immunogenic properties.
"A peptide associated with a pathogenic organism," as used herein,
is a peptide (or fragment or analog thereof) that is normally a
part of a pathogenic organism, or is produced by a pathogenic
organism. Generally, a peptide associated with a pathogenic
organism is one that is recognized as foreign by a normal
individual with a healthy, intact immune system, e.g., the peptide
is displayed together with an MHC Class I molecule on the surface
of a cell, where it is recognized by a CD8.sup.+ lymphocyte.
The terms "antigen" and "epitope" are well understood in the art
and refer to the portion of a macromolecule which is specifically
recognized by a component of the immune system, e.g., an antibody
or a T-cell antigen receptor. As used herein, the term "antigen"
encompasses antigenic epitopes, e.g., fragments of an antigen which
are antigenic epitopes. Epitopes are recognized by antibodies in
solution, e.g. free from other molecules. Epitopes are recognized
by T-cell antigen receptor when the epitope is associated with a
class I or class II major histocompatibility complex molecule.
The terms "preventing," "reducing," and "inhibiting," used
interchangeably herein in the context of pathogen infection refer
to reducing the incidence of pathogen infection of a cell which is
susceptible to infection by the pathogen. Reducing pathogen
infection refers to reducing any parameter or event which leads to
pathogen entry into a cell, including, but not limited to, reducing
co-receptor-mediated fusion; reducing entry of the pathogen into
the cell; reducing binding of the pathogen to a cell-surface
chemokine receptor; and reducing binding of the pathogen to a
cell-surface CD4 molecule. The terms also refer to reducing
susceptibility of a cell to infection by a pathogen. The terms also
refer to reducing any undesired effect of binding of a pathogen to
the cell. As used herein, "a cell which is susceptible to infection
by a pathogen" is a cell which can be infected by a pathogen that
establishes infection or otherwise causes disease or symptoms of
disease in a host by interaction with a chemokine receptor.
As used herein the term "isolated" is meant to describe a compound
of interest (e.g., a virus, a peptide, etc.) that is in an
environment different from that in which the compound naturally
occurs. "Isolated" is meant to include compounds that are within
samples that are substantially enriched for the compound of
interest and/or in which the compound of interest is partially or
substantially purified.
As used herein, the term "substantially purified" refers to a
compound that is removed from its natural environment and is at
least 60% free, preferably 75% free, and most preferably 90% free
from other components with which it is naturally associated.
The terms "immunomodulatory nucleic acid molecule,"
"immunostimulatory nucleic acid molecule," "ISS," "ISS-PN," and
"ISS-ODN," are used interchangeably herein to refer to a
polynucleotide that comprises at least one immunomodulatory nucleic
acid moiety. The terms "immunomodulatory," and "immunostimulatory,"
as used herein in reference to a nucleic acid molecule, refer to
the ability of a nucleic acid molecule to modulate an immune
response in a vertebrate host. In particular, these terms refer to
the ability of an immunostimulatory nucleic acid molecule to
increase an immune response in a vertebrate host, particularly to
increase a CTL response, particularly an antigen-specific CTL
response.
The terms, "increasing," "inducing," and "enhancing," used
interchangeably herein with reference to a CTL response, refer to
any increase in a CTL response over background, and include
inducing a CTL response over an absence of a measurable CTL
response, or increasing CTL response over a previously measurable
CTL response.
The terms "CD4.sup.+ -deficient" and "CD4.sup.+ -low" are used
interchangeably herein, and, as used herein, refer to a state of an
individual in whom the number of CD4.sup.+ T lymphocytes is reduced
compared to an individual with a healthy, intact immune system.
CD4.sup.+ deficiency includes a state in which the number of
functional CD4.sup.+ T lymphocytes is less than about 600 CD4.sup.+
T cells/mm.sup.3 blood; a state in which the number of functional
CD4.sup.+ T cells is reduced compared to a healthy, normal state
for a given individual; and a state in which functional CD4.sup.+ T
cells are completely absent.
As used herein, a "CD4.sup.+ -deficient individual" is one who has
a reduced number of functional CD4.sup.+ -T cells, regardless of
the reason, when compared to an individual having a normal, intact
immune system. In general, the number of functional CD4.sup.+ -T
cells that is within a normal range is known for various mammalian
species. In human blood, e.g., the number of functional CD4.sup.+
-T cells which is considered to be in a normal range is from about
600 to about 1500 CD4.sup.+ -T cells/mm.sup.3 blood. An individual
having a number of CD4.sup.+ -T cells below the normal range, e.g.,
below about 600/mm.sup.3, may be considered "CD4.sup.+ -deficient."
Thus, a CD4.sup.+ -deficient individual may have a low CD4.sup.+ T
cell count, or even no detectable CD4.sup.+ cells. A CD4.sup.+
-deficient individual includes an individual who has a lower than
normal number of functional CD4.sup.+ -T cells due to a primary or
an acquired immunodeficiency.
A "functional CD4.sup.+ -T cell" is a term well understood in the
art and refers to a CD4.sup.+ -T cell which is capable of providing
T cell help, directly or indirectly, to effect one or more of the
following responses: CTL activation; antibody production;
macrophage activation; mast cell growth; and eosinophil growth and
differentiation.
As used herein, the terms "immunodeficient," "immunosuppressed,"
and "immunocompromised," used interchangeably herein, refer to a
state of a CD4.sup.+ -deficient individual.
As used herein, the term "soluble exogenous antigen" refers to an
antigen that a cell takes up from its environment, and processes
intracellularly. A "soluble exogenous antigen" is distinguished
from an antigen that is synthesized intracellularly (e.g.,
translated in the cell cytoplasm).
As used herein, the terms "treatment", "treating", and the like,
refer to obtaining a desired pharmacologic and/or physiologic
effect. The effect may be prophylactic in terms of completely or
partially preventing a disease or symptom thereof and/or may be
therapeutic in terms of a partial or complete cure for a disease
and/or adverse affect attributable to the disease. "Treatment", as
used herein, covers any treatment of a disease in a mammal,
particularly in a human, and includes: (a) preventing the disease
from occurring in a subject which may be predisposed to the disease
but has not yet been diagnosed as having it; (b) inhibiting the
disease, i.e., arresting its development; and (c) relieving the
disease, e.g., causing regression of the disease, e.g., to
completely or partially remove symptoms of the disease.
The term "biological sample" encompasses a variety of sample types
obtained from an organism and can be used in a diagnostic or
monitoring assay. The term encompasses blood and other liquid
samples of biological origin, solid tissue samples, such as a
biopsy specimen or tissue cultures or cells derived therefrom and
the progeny thereof. The term encompasses samples that have been
manipulated in any way after their procurement, such as by
treatment with reagents, solubilization, or enrichment for certain
components. The term encompasses a clinical sample, and also
includes cells in cell culture, cell supernatants, cell lysates,
serum, plasma, biological fluids, and tissue samples.
The terms "cancer", "neoplasm", "tumor", and "carcinoma", are used
interchangeably herein to refer to cells which exhibit relatively
autonomous growth, so that they exhibit an aberrant growth
phenotype characterized by a significant loss of control of cell
proliferation. Cancerous cells can be benign or malignant.
By "individual" or "host" or "subject" or "patient" is meant any
mammalian subject for whom diagnosis, treatment, or therapy is
desired, particularly humans. Other subjects may include cattle,
dogs, cats, guinea pigs, rabbits, rats, mice, horses, and so
on.
Methods of Increasing an Antigen-Specific CTL Response in Vivo
The invention provides methods for induction of a CTL response to
any exogenous soluble antigen via a process of cross-presentation.
In addition, the invention provides methods for T
helper-independent activation of an antigen-specific cytotoxic T
lymphocyte response in an individual; methods for decreasing the
number of infectious pathogens in an individual; methods for
decreasing tumor load in an individual; and methods of treating an
infectious disease in an individual. The methods generally involve
administering to an individual an immunostimulatory nucleic acid
molecule (either alone or in combination with one or more antigens)
in an amount effective to increase an antigen-specific CTL response
in the individual and/or to decrease a tumor load in an individual
and/or to prevent and/or reduce an infectious disease in an
individual.
During an immune response, an antigen presenting cell (APC)
presents antigen to T lymphocytes, and the result may be production
of antigen-specific antibody, and activation of antigen-specific
cytotoxic cells which serve to destroy cells displaying foreign
antigen on their cell surface. It was previously believed that
CD4.sup.+ cells were required for CTL activation. Without wishing
to be bound by theory, immunostimulatory nucleic acid molecules may
bypass the requirement for CD4.sup.+ cells, and may induce APC's to
activate a CTL response directly, even in the absence of CD4.sup.+
cells, or in the presence of an insufficient number of functional
CD4.sup.+ cells. The present invention provides a means for
increasing antigen-specific CTL activity even in the absence of
CD4.sup.+ cells.
The results presented in the Examples also demonstrate that an
immunostimulatory nucleic acid molecule can, when administered
together with a soluble exogenous antigen, increase both an
antigen-specific CTL response to the soluble antigen and
cross-reacting epitopes, as well as an antigen-specific humoral
response to the soluble antigen and cross-reacting epitopes.
T lymphocytes capable of antigen recognition are generally
classified as "CD4.sup.+ " or "CD8.sup.+," depending on whether a
CD4 or a CD8 molecule is displayed on the cell surface. CD4.sup.+
cells recognize exogenously-produced antigen which has been taken
up by an antigen presenting cell (APC), processed, and displayed on
the APC cell surface together with a major histocompatibility
complex (MHC) class II molecule. In general, CD4.sup.+ T cells
provide the signals to activate other cells, e.g., CD4.sup.+ cells
activate CD8.sup.+ cells, to induce B cell to produce antibodies,
or to activate macrophages. In contrast, CD8.sup.+ cells are
cytotoxic, and recognize antigen produced from within a cell and
displayed on the cell surface together with an MHC Class I
molecule.
In general, CD4.sup.+ helper T (Th) cells are divided into broad
groups based on their specific profiles of cytokine production:
Th1, Th2, and Th0. "Th1" cells are T lymphocytes that release
predominantly the cytokines IL-2 and IFN-.gamma., which cytokines
in turn promote T cell proliferation, facilitate macrophage
activation, and enhance the cytolytic activity of natural killer
(NK) cells and antigen-specific cytotoxic T cells (CTL). In
contrast, the cytokines predominantly released by Th2 cells are
IL-4, IL-5, and IL-10. IL-4 and IL-5 are known to mediate antibody
isotype switching towards IgE or IgA response, and promote
eosinophil recruitment, skewing the immune system toward an
"allergic" type of response. ThO cells release a set of cytokines
with characteristics of both Th1-type and Th2-type responses. While
the categorization of T cells as Th1, Th2, or Th0 is helpful in
describing the differences in immune response, it should be
understood that it is more accurate to view the T cells and the
responses they mediate as forming a continuum, with Th1 and Th2
cells at opposite ends of the scale, and Th0 cells providing the
middle of the spectrum. Therefore, it should be understood that the
use of these terms herein is only to describe the predominant
nature of the immune response elicited, and is not meant to be
limiting to an immune response that is only of the type indicated.
Thus, for example, reference to a "type-1" or "Th1" immune response
is not meant to exclude the presence of a "type-2" or "Th2" immune
response, and vice versa.
The immunostimulatory nucleic acid molecule may be administered
before, simultaneously with (e.g., in admixture with antigen, or
covalently or non-covalently bound, directly or via a linker, to an
antigen or antigenic epitope), or after the subject is exposed to
antigen. Exposure to antigen may occur by intentionally introducing
the antigen into the subject via a systemic or mucosal route, e.g.,
intranasally, intrarectally, intravenously, subcutaneously,
intradermally, or intraperitoneally, and the like, e.g., by a
clinician. Alternatively, exposure to antigen may occur
accidentally or naturally (e.g., by happenstance), e.g., by the
usual routes of exposure of a subject to plant, animal, and other
antigens, such as by inhalation, accidental skin exposure,
ingestion, and the like.
Methods of T helper-independent Activation of an Antigen-specific
CTL Response
The present invention provides methods of increasing an
antigen-specific CTL response in an individual, comprising
administering a formulation comprising an immunostimulatory nucleic
acid molecule to the individual.
An antigen-specific CTL response may be directed to an
intracellular pathogen, such as a virus, an intracellular
bacterium, fungus, or protozoan; or may be directed to a
tumor-associated antigen. Pathogens include microorganisms that are
commonly pathogenic in healthy individuals with an intact immune
system, as well as microorganisms that cause opportunistic
infections in individuals who are immunocompromised.
In general, the methods for increasing an antigen-specific CTL
response are effective to increase an antigen-specific CTL response
by at least about 10%, at least about 20%, at least about 25%, at
least about 50%, at least about 75%, at least about 100% (or
two-fold), at least about 5-fold, at least about 10-fold, at least
about 20-fold, at least about 50-fold, or at least about 100-fold
or more, when compared to a suitable control. Thus, in these
embodiments, an "effective amount" of an immunostimulatory nucleic
acid molecule is an amount sufficient to increase an
antigen-specific CTL response in an individual by at least about
10%, at least about 20%, at least about 25%, at least about 50%, at
least about 75%, at least about 100% (or two-fold), at least about
5-fold, at least about 10-fold, at least about 20-fold, at least
about 50-fold, or at least about 100-fold or more, when compared to
a suitable control. In an experimental animal system, a suitable
control may be a genetically identical animal not treated with the
immunostimulatory nucleic acid molecule. In non-experimental
systems, a suitable control may be the level of antigen-specific
CTL present before administering the immunostimulatory nucleic acid
molecule. Other suitable controls may be a placebo control.
In some embodiments, an immunostimulatory nucleic acid molecule is
co-administered with a soluble exogenous antigen. In certain
embodiments, the immunostimulatory nucleic acid molecule and
soluble exogenous antigen are admixed with one another; in certain
other embodiments, the immunostimulatory nucleic acid molecule and
soluble exogenous antigen are linked to one another (e.g., either
covalently or non-covalently, e.g., to place the antigen and the
immunostimulatory nucleic acid molecule in spatial proximity at a
distance sufficient to provide for the desired immunomodulatory
effect). Co-administration of an immunostimulatory nucleic acid
molecule and a soluble exogenous antigen results in an increase in
both antigen-specific CTL response and antigen-specific humoral
response. An antigen-specific CTL response to a soluble exogenous
antigen encompasses a CTL response to an epitope that is shared
between the soluble exogenous antigen and another protein.
Whether an antigen-specific CTL response is increased can be
determined using any of a number of assays known in the art,
including, but not limited to, measuring specific lysis by CTL of
target cells expressing antigen on their surface, which target
cells have incorporated a detectable label which is released from
target cells upon lysis, and can be measured, using, e.g., an assay
such as that described in the Examples, a .sup.51 Cr-release assay,
a lanthanide fluorescence-based cytolysis assay, and the like.
An immunostimulatory nucleic acid molecule can also elicit
production of IFN.gamma. in CD4-deficient individuals. Thus, in
some embodiments, the invention provides methods of increasing
IFN.gamma. production in a CD4+ T cell deficient individual,
comprising administering a formulation comprising an
immunostimulatory nucleic acid molecule to the individual. In many
embodiments, an immunostimulatory nucleic acid molecule is
administered together with (e.g., in admixture, as a conjugate,
etc.) an antigen. In these embodiments, IFN.gamma. is produced in
an antigen-specific manner, e.g., IFN.gamma. is produced in
response to the antigen administered, to an epitope contained on
the administered antigen, or to a cross-reactive antigen or
epitope, but not to an unrelated antigen. IFN.gamma. is produced in
an antigen-specific manner by CD8.sup.+ cells in CD4.sup.+
-deficient individuals. In the context of IFN.gamma. production, an
"effective amount" of an immunostimulatory nucleic acid molecule is
an amount sufficient to increase production of IFN.gamma. in an
individual by at least about 10%, at least about 20%, at least
about 25%, at least about 50%, at least about 75%, at least about
100% (or two-fold), at least about 5-fold, at least about 10-fold,
at least about 20-fold, at least about 50-fold, or at least about
100-fold or more, when compared to a suitable control, as described
above.
Whether IFN.gamma. production is increased can be determined using
any known assay. A non-limiting example of such an assay is an
enzyme-linked immunosorbent assay, using antibody specific for
IFN.gamma..
Methods of Decreasing Tumor Load in an Individual
The present invention further provides methods for decreasing tumor
load in an individual, comprising administering a formulation
comprising an immunostimulatory nucleic acid molecule to the
individual, in an amount effective to reduce the tumor load.
The methods are effective to reduce a tumor load by at least about
5%, at least about 10%, at least about 20%, at least about 25%, at
least about 50%, at least about 75%, at least about 85%, or at
least about 90%, up to total eradication of the tumor, when
compared to a suitable control. Thus, in these embodiments, an
"effective amount" of an immunostimulatory nucleic acid molecule is
an amount sufficient to reduce a tumor load by at least about 5%,
at least about 10%, at least about 20%, at least about 25%, at
least about 50%, at least about 75%, at least about 85%, or at
least about 90%, up to total eradication of the tumor, when
compared to a suitable control. In an experimental animal system, a
suitable control may be a genetically identical animal not treated
with the immunostimulatory nucleic acid molecule. In
non-experimental systems, a suitable control may be the tumor load
present before administering the immunostimulatory nucleic acid
molecule. Other suitable controls may be a placebo control.
Whether a tumor load has been decreased can be determined using any
known method, including, but not limited to, measuring solid tumor
mass; counting the number of tumor cells using cytological assays;
fluorescence-activated cell sorting (e.g., using antibody specific
for a tumor-associated antigen); computed tomography scanning,
magnetic resonance imaging, and/or x-ray imaging of the tumor to
estimate and/or monitor tumor size; measuring the amount of
tumor-associated antigen in a biological sample, e.g., blood; and
the like.
Methods of Preventing or Treating an Infectious Disease in an
Individual
The present invention further provides methods for preventing or
treating an infectious disease in an individual, comprising
administering a formulation comprising an immunostimulatory nucleic
acid molecule to the individual, in an amount effective to prevent
or treat the disease. The methods are particularly useful for
preventing or treating infectious diseases caused by intracellular
pathogens, such as viruses, intracellular bacteria, fungi and
parasites (e.g. protozoans). In particular, opportunistic
infections can be treated using the methods of the invention.
"Preventing an infectious disease," as used herein, refers to
reducing the likelihood that an individual, upon infection by a
pathogenic organism, will exhibit the usual symptoms of a disease
caused by a pathogenic organism.
"Treating an infectious disease," as used herein, encompasses
reducing the number of pathogenic agents in the individual (e.g.,
reducing viral load) and/or reducing a parameter associated with
the infectious disease, including, but not limited to, reduction of
a level of a product produced by the infectious agent (e.g., a
toxin, an antigen, and the like); and reducing an undesired
physiological response to the infectious agent (e.g., fever, tissue
edema, and the like).
The methods are effective to treat an infectious disease by at
least about 5%, at least about 10%, at least about 20%, at least
about 25%, at least about 50%, at least about 75%, at least about
85%, or at least about 90%, up to total eradication of the
infecting pathogen and/or an associated parameter, when compared to
a suitable control. Thus, in these embodiments, an "effective
amount" of an immunostimulatory nucleic acid molecule is an amount
sufficient to treat an infectious disease, e.g., to reduce the
number of pathogens and/or reduce a parameter associated with the
presence of a pathogen, by at least about 5%, at least about 10%,
at least about 20%, at least about 25%, at least about 50%, at
least about 75%, at least about 85%, or at least about 90%, up to
total eradication of the infectious disease, when compared to a
suitable control. In an experimental animal system, a suitable
control may be a genetically identical animal not treated with the
immunostimulatory nucleic acid molecule. In non-experimental
systems, a suitable control may be the infectious disease present
before administering the immunostimulatory nucleic acid molecule.
Other suitable controls may be a placebo control.
Whether an infectious disease has been treated can be determined in
any of a number of ways, including but not limited to, measuring
the number of infectious agents in the individual being treated,
using methods standard in the art; measuring a parameter caused by
the presence of the pathogen in the individual, e.g., measuring the
levels of a toxin produced by the pathogen; measuring body
temperature; measuring the level of any product produced by the
pathogen; measuring or assessing any undesired physiological
parameter associated with the presence of an infectious agent in an
individual. Measuring the number of infectious agents can be
accomplished by any conventional assay, such as those typically
used in clinical laboratories, for evaluating numbers of pathogens
present in a biological sample obtained from an individual. Such
methods have been amply described in the literature, including,
e.g., Medical Microbiology 3rd Ed., (1998) P. R. Murray et al.,
eds. Mosby-Year Book, Inc. A level of a product, including a toxin,
produced by a pathogen can be measured using conventional
immunological assays, using antibody which detects the product,
including, but not limited to enzyme-linked immunosorbent assays
(ELISA), radioimmunoassays. Other assays, include in vivo assays
for toxins.
Subjects Suitable for Treatment with the Methods of the
Invention
Subjects suitable for treatment with the methods of the invention
include an individual who has been infected with a pathogenic
microorganism; an individual who is susceptible to infection by a
pathogenic microorganism, but who has not yet been infected; and an
individual who has a tumor.
Subjects particularly suitable for treatment with the methods of
the invention include CD4.sup.+ -deficient individuals, e.g.,
individuals who have lower than normal numbers of functional
CD4.sup.+ T lymphocytes. As used herein, the term "normal
individual" refers to an individual having CD4.sup.+ T lymphocyte
levels and function(s) within the normal range in the population,
for humans, typically 600 to 1500 CD4.sup.+ T lymphocytes per
mm.sup.3 blood. CD4.sup.+ -deficient individuals individuals who
have an acquired immunodeficiency, or a primary immunodeficiency.
An acquired immunodeficiency may be a temporary CD4.sup.+
deficiency, such as one caused by radiation therapy, or
chemotherapy, as described below.
Also suitable for treatment with the methods of the invention are
individuals with healthy, intact immune systems, but who are at
risk for becoming CD4.sup.+ deficient ("at-risk" individuals).
At-risk individuals include, but are not limited to, individuals
who have a greater likelihood than the general population of
becoming CD4.sup.+ deficient. Individuals at risk for becoming
CD4.sup.+ deficient include, but are not limited to, individuals at
risk for HIV infection due to sexual activity with HIV-infected
individuals; intravenous drug users; individuals who may have been
exposed to HIV-infected blood, blood products, or other
HIV-contaminated body fluids; babies who are being nursed by
HIV-infected mothers; individuals who were previously treated for
cancer, e.g., by chemotherapy or radiotherapy, and who are being
monitored for recurrence of the cancer for which they were
previously treated; and individuals who have undergone bone marrow
transplantation or any other organ transplantation.
A reduction of normal levels and/or function of CD4.sup.+ T
lymphocytes compared to a normal individual can result from a
variety of disorders, diseases infections or conditions, including
immunosuppressed conditions due to leukemia, renal failure;
autoimmune disorders, including, but not limited to, systemic lupus
erythematosus, rheumatoid arthritis, auto-immune thyroiditis,
scleroderma, inflammatory bowel disease; various cancers and
tumors; viral infections, including, but not limited to, human
immunodeficiency virus (HIV); bacterial infections; and parasitic
infections.
A reduction of normal levels and/or function of CD4.sup.+ T
lymphocytes compared to a normal individual can also result from an
immundeficiency disease or disorder of genetic origin, or due to
aging. Examples of these are immunodeficiency diseases associated
with aging and those of genetic origin, including, but not limited
to, hyperimmunoglobulin M syndrome, CD40 ligand deficiency, IL-2
receptor deficiency, .gamma.-chain deficiency, common variable
immunodeficiency, Chediak-Higashi syndrome, and Wiskott-Aldrich
syndrome.
A reduction of normal levels and/or function of CD4.sup.+ T
lymphocytes compared to a normal individual can also result from
treatment with specific pharmacological agents, including, but not
limited to chemotherapeutic agents to treat cancer; certain
immunotherapeutic agents; radiation therapy; immunosuppressive
agents used in conjunction with bone marrow transplantation; and
immunosuppressive agents used in conjunction with organ
transplantation.
Accordingly, individuals who may benefit from treatment using the
methods of the present invention include, but are not limited to,
individuals with various cancers, including, but not limited to,
leukemia, Hodgkin's disease, lung cancer, colon cancer, gliomas,
renal cell carcinoma, etc.; individuals with various bacterial,
protozoan, and viral infections, including, but not limited to,
patients with acquired immunodeficiency syndrome (AIDS),
cytomegalovirus infections, malaria, Epstein Barr Virus, etc.;
individuals infected with intracellular pathogens, including, but
not limited to, individuals with leprosy, tuberculosis, leishmania;
individuals with autoimmune diseases, including, but not limited to
systemic lupus erythematosus, rheumatoid arthritis, scleroderma,
autoimmune thyroiditis; and individuals who have undergone stem
cell replacement therapy, organ transplantation, bone marrow
transplant, chemotherapy, radiotherapy and the like.
Methods of Increasing Chemokine Secretion
The present invention provides methods for increasing chemokine
production and secretion by a cell. The methods are useful for
treating various disorders which are mediated by cells expressing
chemokine receptors. In some embodiments, the methods are carried
out in vitro or ex vivo. In these embodiments, the methods
generally involve contacting the cell with an immunostimulatory
nucleic acid molecule in an amount sufficient to increase secretion
of a chemokine. In other embodiments, the methods are carried out
in vivo. In these embodiments, the methods generally involve
administering to an individual an immunostimulatory nucleic acid
molecule in an amount sufficient to increase secretion of a
chemokine. In some embodiments, the invention provides methods for
increasing chemokine production and secretion in an antigen
non-specific manner. In these embodiments, cells are contacted
with, or individuals are administered with, immunostimulatory
nucleic acid molecule without antigen. In other embodiments, the
invention provides methods for increasing chemokine production and
secretion in an antigen-specific manner. In these embodiments,
immunostimulatory nucleic acid molecule and antigen are brought
into contact with cells, or administered to an individual.
The methods of the invention increase secretion of a chemokine from
a cell that normally produces a chemokine, particularly those cells
that are susceptible to infection by a pathogen. Cells that
normally produce chemokines include, but are not limited to, T
lymphocytes, macrophages, monocytes, dendritic cells and related
antigen-presenting cells (APCs), B lymphocytes, epithelial cells,
fibroblasts, endothelial cells, basophils, eosinophils,
neutrophils, natural killer cells, and bone marrow stem cells.
Chemokines whose secretion is increased by contacting a cell that
normally produces a chemokine with an immunostimulatory nucleic
acid molecule include, but are not limited to, MIP-1.alpha., and
MIP-1.beta.. Other chemokines which may have increased secretion in
response to immunostimulatory nucleic acid include, but are not
necessarily limited to, RANTES, SDF-1, MCP-1, MCP-2, MCP-3, MCP-4,
eotaxin, eotaxin-2,I-309/TCA3, ATAC, HCC-1, HCC-2, HCC-3,
LARC/MIP-3.alpha., PARC, TARC, CK.beta.4, CK.beta.6, CK.beta.7,
CK.beta.8, CK.beta.9, CK.beta.11, CK.beta.12, and CK.beta.13, C10,
an interleukin-8 (IL-8) family member; GRO.alpha., GRO.beta.,
GRO.gamma., mouse KC, mouse MIP-2, ENA-78, GCP-2,
PBP/CTAPIII/.beta.-TG/NAP-2, IP-10/mouse CRG, Mig, PBSF/SDF-1, a
member of the platelet factor 4 (PF4) family, lymphotactin, or an
equivalent in any mammalian species of any of the foregoing.
In some embodiments, the cells are susceptible to infection with a
pathogen that exploits a chemokine receptor to establish infection
and/or cause disease symptoms, e.g., an immunodeficiency virus. In
some of these embodiments, the cells are macrophages and/or
monocytes and/or T cells. In particular embodiments, the cells are
macrophages and/or monocytes, and/or T lymphocytes, and the
chemokines are MIP-1.alpha., and/or MIP-1.beta., and/or RANTES.
In some embodiments, methods are provided for increasing chemokine
secretion in an antigen non-specific manner. In these embodiments,
an immunostimulatory nucleic acid molecule is brought into contact
with a cell, or administered to an individual, in the absence of
exogenously provided antigen, i.e., antigen is not intentionally
introduced into the individual, either before, simultaneously with,
or after introduction of the immunostimulatory nucleic acid
molecule into the individual.
In particular embodiments, production and secretion of a chemokine
is antigen-specific. The term "antigen-specific" is one well
understood in the art, and refers to chemokine production in
response to the antigen with which the individual is immunized, or
to closely related ("cross-reactive") antigens, e.g., antigens that
share one or more epitopes with the immunizing antigen. In in vivo
embodiments, the method generally involves administering to an
individual an immunostimulatory nucleic acid molecule and an
antigen, wherein the immunostimulatory nucleic acid molecule is
administered in an amount sufficient to increase secretion of a
chemokine in an antigen-specific manner. In in vitro or ex vivo
embodiments, the method generally involves contacting a cell with
an immunostimulatory nucleic acid molecule and an antigen, wherein
the cell is contacted with immunostimulatory in an amount
sufficient to increase secretion of a chemokine in an
antigen-specific manner.
The immunostimulatory nucleic acid molecule and the antigen may be
administered substantially simultaneously, or the immunostimulatory
nucleic acid molecule may be administered before or after the
antigen. Generally, the immunostimulatory nucleic acid molecule and
the antigen are administered within about 72 hours, about 48 hours,
about 24 hours, about 12 hours, about 8 hours, about 4 hours, about
2 hours, about I hour, or about 30 minutes or less, of each
other.
Antigen may be administered separately from the immunostimulatory
nucleic acid molecule, in admixture with immunostimulatory nucleic
acid molecule, or the immunostimulatory nucleic acid and antigen
can be proximately associated with (e.g., conjugated or brought
into spatial proximation by other means, as described in more
detail below) to one or more immunostimulatory nucleic acid
molecules. Generally, and most preferably, an immunomodulatory
nucleic acid and an antigen are proximately associated at a
distance effective to enhance the immune response generated
compared to the administration of the ISS and antigen as an
admixture. For a detailed discussion of method for proximate
association of a polynucleotide and an antigen see, e.g., PCT
Publication WO 00/21556, incorporated herein by reference.
Whether chemokine secretion is increased in an antigen-specific
manner can be readily determined by those skilled in the art using
standard methods. As one non-limiting example, splenocytes from an
individual immunized with immunostimulatory nucleic acid molecule
plus antigen are cultured in the presence of the immunizing
antigen, and secretion of chemokines measured using any known
method, as described below.
In vitro and ex vivo methods of the invention comprise contacting a
cell that normally produces a chemokine with an immunostimulatory
nucleic acid molecule. In these embodiments, contacting a cell that
normally produces a chemokine with an immunostimulatory nucleic
acid molecule increases chemokine secretion from the cell by at
least about 10%, at least about 25%, at least about 30%, at least
about 50%, at least about 75%, at least about 100% (or two-fold),
at least about five fold, at least about 10 fold, at least about 15
fold, at least about 25 fold, at least about 50 fold, at least
about 75 fold, at least about 100 fold, at least about 200 fold, at
least about 300 fold, at least about 400 fold, at least about 500
fold, at least about 600 fold, at least about 700 fold, at least
about 800 fold, at least about 900 fold, at least about 1000 fold,
at least about 2000 fold, at least about 3000 fold, at least about
4000 fold, at least about 5000 fold, or at least about 10,000 fold
or more, when compared the level of secretion of the chemokine from
the cell not contacted with the immunostimulatory nucleic acid
molecule.
In vivo methods of the invention comprise administering to an
individual an immunostimulatory nucleic acid molecule in an amount
sufficient to increase secretion of a chemokine from a cell that
normally produces a chemokine. A "sufficient amount," used
interchangeably in this context with "an effective amount," is an
amount of immunostimulatory nucleic acid molecule sufficient to
increase chemokine secretion such that the level of chemokine
produced is increased by at least about 10%, at least about 25%, at
least about 30%, at least about 50%, at least about 75%, at least
about 100% (or two-fold), at least about five fold, at least about
10 fold, at least about 15 fold, at least about 25 fold, at least
about 50 fold, at least about 75 fold, at least about 100 fold, at
least about 200 fold, at least about 300 fold, at least about 400
fold, at least about 500 fold, at least about 600 fold, at least
about 700 fold, at least about 800 fold, at least about 900 fold,
at least about 1000 fold, at least about 2000 fold, at least about
3000 fold, at least about 4000 fold, at least about 5000 fold, or
at least about 10,000 fold or more, when compared the level of
chemokine in the individual before being administered with the
immunostimulatory nucleic acid molecule.
Whether, and to what extent, an immunostimulatory nucleic acid
molecule increases chemokine secretion from a cell that normally
produces (e.g., is capable of producing) can be readily determined
using any known assay method. The amount of chemokine secreted from
a cell can be determined quantitatively (e.g., the amount secreted
measured) or semi-quantitatively (e.g., the amount secreted
relative to a control determined). Levels of chemokine can be
determined using any method known in the art, including a
biochemical assay, an immunological assay, or a biological assay.
Immunological assays include, but are not limited to,
radioimmunoassays, and enzyme-linked immunosorbent assays (ELISA),
a number of which are commercially available. Assays can be
conducted in vitro, e.g., by adding an immunostimulatory nucleic
acid molecule to the cell culture medium of an in vitro cell
culture, and, after a suitable time (e.g., about 10 minutes to
about 24 hours), determining the level of chemokine in the cell
culture supernatant.
Biological assays include, but are not limited to, in vitro assays
to detect pathogen binding to and/or entry into a cell bearing a
chemokine receptor on its surface, which receptor serves as a
receptor or co-receptor for infection by the pathogen or as a
receptor or co-receptor for a pathogen-derived ligand that elicits
disease symptoms or causes disease. Any known assay to determine
infection of a cell with a pathogen can be used. For example,
binding or infection by an immunodeficiency virus can be detected
by syncitia formation, cytopathic effects, production of an
immunodeficiency virus-encoded polypeptide, e.g. p24, and/or
reverse transcriptase, and/or gp120.
As one non-limiting example, the following protocol can be used.
Peripheral blood mononuclear cells (PBMC) cultures are infected
with a virus stock. Virus is harvested when p24 or reverse
transcriptase (RT) is detected in the supernatant. Dilutions of a
solution (e.g., a cell culture supernatant) are mixed with target
phytohemagglutinin-(PHA-) and IL-2-stimulated PBMCs and incubated
at 37.degree. C. for 30 minutes, and are then exposed to an equal
volume of virus supernatant containing 1000 times the median tissue
culture infectious dose (TCID50), and reincubated at 37.degree. C.
for 3 hours. Input virus is then washed out before adding growth
medium containing appropriate chemokine concentrations. The
cultures are incubated at 37 C. for up to 12 days with medium
changes twice weekly but without further addition of chemokine.
Virus production into the supernatant is assessed by measurement of
RT activity using a sensitive nonradioactive method (e.g., a
commercially available assay, e.g., the Retrosys RT activity kit
from Innovagen AB, Lund, Sweden). Simmons et al. (1997) Science
276:276-279.
Disorders Amenable to Treatment by the Methods of the Invention
Diseases or conditions of humans or other mammals which are
amenable to treatment by increasing chemokine secretion include,
but are not limited to, immunosuppression, such as that in
individuals with immunodeficiency syndromes such as acquired
immunodeficiency syndrome (AIDS); infection by an immunodeficiency
virus, including, but not limited to human immunodeficiency virus
(HIV) (including any known subtype), simian immunodeficiency virus,
and feline immunodeficiency virus; radiation therapy, chemotherapy,
immunosuppressive therapy for an autoimmune disease, or other drug
therapy which causes immunosuppression; immunosuppression due to
congenital deficiency in receptor function or other causes; chronic
infectious diseases, including, but not limited to, hepatitis B and
hepatitis C infections; and infectious diseases, such as parasitic
diseases, including but not limited to, leshmaniasis, helminth
infections, such as nematodes, trematodes, cestodes, visceral
worms, visceral larva migrans, and the like.
Methods of Reducing Entry of a Pathogen into a Cell
The present invention further provides methods for reducing entry
of a pathogen, e.g., an immunodeficiency virus, into a cell. The
methods generally involve contacting the cell with an
immunostimulatory nucleic acid molecule. The methods are useful for
reducing infection with an immunodeficiency virus in an
individual.
In the context of methods of reducing pathogen entry into a
susceptible cell, an effective amount of an immunostimulatory
nucleic acid molecule is one that increases chemokine secretion
from a cell and reduces infection by the pathogen into the same
cell or cells in the vicinity of the chemokine-producing cell. The
cell secreting chemokine and the cell susceptible to infection by
the pathogen may be the same cell, but need not be.
As used herein, "reducing pathogen entry into a cell susceptible to
pathogen infection" encompasses reducing pathogen entry into a cell
susceptible to pathogen infection, reducing pathogen binding to a
cell susceptible to pathogen infection. In this context, the terms
"reducing" and "inhibiting" and "preventing" are used
interchangeably herein.
Methods of the invention for reducing pathogen entry into a cell
susceptible to pathogen infection are also useful for treating a
pathogen infection. "Treating a pathogen infection," as used
herein, includes, but is not limited to, preventing an infection in
an individual who does not yet have a clinically detectable
infection; reducing the probability of an infection in an
individual who does not yet have a clinically detectable infection;
reducing spread of pathogen from an infected cell to a cell not yet
infected but susceptible to infection; improving one or more
indicia of an infection. For example, treating an HIV infection,
includes, but is not limited to, preventing HIV infection, reducing
the probability of HIV infection, reducing the spread of HIV from
an infected cell to a susceptible cell, reducing viral load in an
HIV-infected individual, reducing an amount of virally-encoded
polypeptide(s) in an HIV-infected individual, and increasing CD4 T
cell count in an HIV-infected individual.
Methods of determining whether the methods of the invention are
effective in reducing pathogen-induced disease in a susceptible
cell include any known test for infection by a given pathogen,
including, but not limited to, measuring the number of pathogens in
a biological sample from a host, e.g., by using a PCR with primers
specific for a nucleotide sequence in the pathogen; counting the
number of pathogens in the host; detecting or measuring a
polypeptide or other product produced by the pathogen; and
measuring an indicia of pathogen infection.
For example, methods of determining whether the methods of the
invention are effective in reducing HIV entry into a cell, and/or
treating an HIV infection, are any known test for indicia of HIV
infection, including, but not limited to, measuring viral load,
e.g., by measuring the amount of HIV in a biological sample, e.g.,
using a polymerase chain reaction (PCR) with primers specific for
an HIV polynucleotide sequence; detecting and/or measuring a
polypeptide encoded by HIV, e.g., p24, gp120, reverse
transcriptase, using, e.g., an immunological assay with an antibody
specific for the polypeptide; and measuring CD4 cell count in the
individual. Methods of assaying an HIV infection (or any indicia
associated with an HIV infection) are known in the art, and have
been described in numerous publications such as HIV Protocols
(Methods in Molecular Medicine, 17) N. L. Michael and J. H. Kim,
eds. (1999) Humana Press.
Subjects suitable for treatment with the methods of the invention
include, but are not limited to, individuals infected with a
pathogen; and individuals not yet infected with the pathogen, but
at risk for becoming infected. For example, subjects suitable for
treatment with the methods of the invention include, but are not
limited to, individuals who have been diagnosed as having an HIV
infection; individuals at risk for HIV infection due to sexual
activity with HIV-infected individuals; intravenous drug users;
individuals who may have been exposed to HIV-infected blood, blood
products, or other HIV-contaminated body fluids; babies who are
being nursed by HIV-infected mothers.
Immunostimulatory Nucleic Acid Molecules Suitable for Use in the
Methods of the Invention
The term "polynucleotide," as used in the context of
immunostimulatory nucleic acid molecules, is a polynucleotide as
defined above, and encompasses, inter alia, single- and
double-stranded oligonucleotides (including deoxyribonucleotides,
ribonucleotides, or both), modified oligonucleotides, and
oligonucleosides, alone or as part of a larger nucleic acid
construct, or as part of a conjugate with a non-nucleic acid
molecule such as a polypeptides. Thus immunostimulatory nucleic
acid molecules may be, for example, single-stranded DNA (ssDNA),
double-stranded DNA (dsDNA), single-stranded RNA (ssRNA) or
double-stranded RNA (dsRNA). Immunostimulatory nucleic acid
molecules also encompasses crude, detoxified bacterial (e.g.,
mycobacterial) RNA or DNA, as well as enriched plasmids enriched
for immunostimulatory nucleic acid molecules. In some embodiments,
an "immunostimulatory nucleic acid molecules-enriched plasmid"
refers to a linear or circular plasmid that comprises or is
engineered to comprise a greater number of CpG motifs than normally
found in mammalian DNA. Exemplary immunostimulatory nucleic acid
molecules-enriched plasmids are described in, for example, Roman et
al. (1997) Nat Med. 3(8):849-54. Modifications of oligonucleotides
include, but are not limited to, modifications of the 3'OH or 5'OH
group, modifications of the nucleotide base, modifications of the
sugar component, and modifications of the phosphate group.
An immunostimulatory nucleic acid molecule may comprise at least
one nucleoside comprising an L-sugar. The L-sugar may be
deoxyribose, ribose, pentose, deoxypentose, hexose, deoxyhexose,
glucose, galactose, arabinose, xylose, lyxose, or a sugar "analog"
cyclopentyl group. The L-sugar may be in pyranosyl or furanosyl
form.
Immunostimulatory nucleic acid molecules generally do not provide
for, nor is there any requirement that they provide for, expression
of any amino acid sequence encoded by the polynucleotide, and thus
the sequence of a immunostimulatory nucleic acid molecule may be,
and generally is, non-coding. Immunostimulatory nucleic acid
molecules may comprise a linear double or single-stranded molecule,
a circular molecule, or can comprise both linear and circular
segments. Immunostimulatory nucleic acid molecules may be
single-stranded, or may be completely or partially
double-stranded.
In some embodiments, an immunostimulatory nucleic acid molecule of
the invention is an oligonucleotide, e.g., consists of a sequence
of from about 6 to about 200, from about 10 to about 100, from
about 12 to about 50, or from about 15 to about 25, nucleotides in
length.
In other embodiments, an immunostimulatory nucleic acid molecule is
part of a larger nucleotide construct (e.g., a plasmid vector, a
viral vector, or other such construct). A wide variety of plasmid
and viral vector are known in the art, and need not be elaborated
upon here. A large number of such vectors has been described in
various publications, including, e.g., Current Protocols in
Molecular Biology, (F. M. Ausubel, et al., Eds. 1987, and updates).
Many vectors are commercially available.
Immunostimulatory Nucleic Acid Molecules Comprising a CpG Motif
In some embodiments, the immunostimulatory nucleic acid molecules
used in the invention comprise at least one unmethylated CpG motif.
In general, these immunostimulatory nucleic acid molecules increase
a Th1 response in an individual. The relative position of any CpG
sequence in a polynucleotide having immunostimulatory activity in
certain mammalian species (e.g., rodents) is 5'-CG-3' (i.e., the C
is in the 5' position with respect to the G in the 3' position).
Immunostimulatory nucleic acid molecules can be conveniently
obtained by substituting the cytosine in the CpG dinucleotide with
another nucleotide, particularly a purine nucleotide.
Exemplary immunostimulatory nucleic acid molecules useful in the
invention include, but are not necessarily limited to, those
comprising the following core nucleotide sequences: 1) hexameric
core sequences comprising "CpG" motifs or comprising XpY motifs,
where X cannot be C if Y is G and vice-versa; 2) octameric core
sequences comprising "CpG" motifs or comprising XpY motifs, where X
cannot be C if Y is G and vice-versa; and 3) inosine and/or uracil
substitutions for nucleotides in the foregoing hexameric or
octameric sequences for use as RNA immunostimulatory nucleic acid
molecule (e.g., substituting uracil for thymine and/or substituting
inosine for a purine nucleotide). As used herein, "core sequence"
in the context of an immunostimulatory nucleic acid molecule refers
to a minimal sequence that provides for, factilitates, or confers
the immunostimulatory activity of the nucleic acid molecule.
Exemplary consensus CpG motifs of immunostimulatory nucleic acid
molecules useful in the invention include, but are not necessarily
limited to: 5'-Purine-Purine-[C]-[G]-Pyrimidine-Pyrimidine-3', in
which the immunostimulatory nucleic acid molecule comprises a CpG
motif flanked by at least two purine nucleotides (e.g., GG, GA, AG,
AA, II, etc.,) and at least two pyrimidine nucleotides (CC, TT, CT,
TC, UU, etc.); 5'-Purine-TCG-Pyrimidine-Pyrimidine-3';
5'-[TCG].sub.n -3', where n is any integer that is 1 or greater,
e.g., to provide a poly-TCG immunostimulatory nucleic acid molecule
(e.g., where n=3, the polynucleotide comprises the sequence
5'-TCGTCGTCG-3'); and 5'-Purine-Purine
-CG-Pyrimidine-Pyrimidine-CG-3'.
The core structure of immunostimulatory nucleic acid molecules
useful in the invention may be flanked upstream and/or downstream
by any number or composition of nucleotides or nucleosides. In some
embodiments, the core sequence of immunostimulatory nucleic acid
molecules are at least 6 bases or 8 bases in length, and the
complete immunostimulatory nucleic acid molecules (core sequences
plus flanking sequences 5', 3' or both) are usually between 6 bases
or 8 bases, and up to about 200 bases in length to enhance uptake
of the immunostimulatory nucleic acid molecules. Those of ordinary
skill in the art will be familiar with, or can readily identify,
reported nucleotide sequences of known immunostimulatory nucleic
acid molecules for reference in preparing immunostimulatory nucleic
acid molecules, see, e.g., Yamamoto, et al., (1992) Microbiol.
Immunol., 36:983; Ballas, et al., (1996) J. Immunol., 157:1840;
Klinman, et al., (1997) J. Immunol, 158:3635; Sato, et al., (1996)
Science, 273:352, each of which are incorporated herein by
reference. In addition, immunostimulatory nucleic acid molecules
useful in the invention have been described in, for example, PCT
publication nos. WO 98/16427, WO 98/55495, and WO 99/11275.
Exemplary DNA-based immunostimulatory nucleic acid molecules useful
in the invention include, but are not necessarily limited to,
polynucleotides comprising the following nucleotide sequences:
AGCGCT, AGCGCC, AGCGTT, AGCGTC, AACGCT, AACGCC, AACGTT, AACGTC,
GGCGCT, GGCGCC, GGCGTT, GGCGTC, GACGCT, GACGCC, GACGTT, GACGTC,
GTCGTC, GTCGCT, GTCGTT, GTCGCC, ATCGTC, ATCGCT, ATCGTT, ATCGCC,
TCGTCG, and TCGTCGTCG.
Exemplary DNA-based immunostimulatory nucleic acid molecules useful
in the invention include, but are not necessarily limited to,
polynucleotides comprising the following octameric nucleotide
sequences: AGCGCTCG, AGCGCCCG, AGCGTTCG, AGCGTCCG, AACGCTCG,
AACGCCCG, AACGTTCG, AACGTCCG, GGCGCTCG, GGCGCCCG, GGCGTTCG,
GGCGTCCG, GACGCTCG, GACGCCCG, GACGTTCG, and GACGTCCG.
Immunostimulatory nucleic acid molecules useful in the invention
can comprise one or more of any of the above CpG motifs. For
example, immunostimulatory nucleic acid molecules useful in the
invention can comprise a single instance or multiple instances
(e.g., 2, 3, 5 or more) of the same CpG motif. Alternatively, the
immunostimulatory nucleic acid molecules can comprises multiple CpG
motifs (e.g., 2, 3, 5 or more) where at least two of the multiple
CpG motifs have different consensus sequences, or where all CpG
motifs in the immunostimulatory nucleic acid molecules have
different consensus sequences.
Immunostimulatory nucleic acid molecules useful in the invention
may or may not include palindromic regions. If present, a
palindrome may extend only to a CpG motif, if present, in the core
hexamer or octamer sequence, or may encompass more of the hexamer
or octamer sequence as well as flanking nucleotide sequences.
Modifications
Immunostimulatory nucleic acid molecules of the invention can be
modified in a variety of ways. For example, the immunostimulatory
nucleic acid molecules can comprise backbone phosphate group
modifications (e.g., methylphosphonate, phosphorothioate,
phosphoroamidate and phosphorodithioate internucleotide linkages),
which modifications can, for example, confer inherent
anti-microbial activity on the immunostimulatory nucleic acid
molecule and enhance their stability in vivo, making them
particularly useful in therapeutic applications. A particularly
useful phosphate group modification is the conversion to the
phosphorothioate or phosphorodithioate forms of an
immunostimulatory nucleic acid molecule. In addition to their
potentially anti-microbial properties, phosphorothioates and
phosphorodithioates are more resistant to degradation in vivo than
their unmodified oligonucleotide counterparts, increasing the
half-lives of the immunostimulatory nucleic acid molecules and
making them more available to the subject being treated.
Other modified immunostimulatory nucleic acid molecules encompassed
by the present invention include immunostimulatory nucleic acid
molecules having modifications at the 5' end, the 3' end, or both
the 5' and 3' ends. For example, the 5' and/or 3' end can be
covalently or non-covalently associated with a molecule (either
nucleic acid, non-nucleic acid, or both) to, for example, increase
the bio-availability of the immunostimulatory nucleic acid
molecules, increase the efficiency of uptake where desirable,
facilitate delivery to cells of interest, and the like. Exemplary
molecules for conjugation to the immunostimulatory nucleic acid
molecules include, but are not necessarily limited to, cholesterol,
phospholipids, fatty acids, sterols, oligosaccharides, polypeptides
(e.g., immunoglobulins), peptides, antigens (e.g., peptides, small
molecules, etc.), linear or circular nucleic acid molecules (e.g.,
a plasmid), and the like. Additional immunostimulatory nucleic acid
conjugates, and methods for making same, are known in the art and
described in, for example, WO 98/16427 and WO 98/55495. Thus, the
term "immunostimulatory nucleic acid molecule" includes conjugates
comprising an immunostimulatory nucleic acid molecule. The
immunostimulatory nucleic acid molecule and the antigen may be
administered substantially simultaneously, or the immunostimulatory
nucleic acid molecule may be administered before or after the
antigen. Generally, the immunostimulatory nucleic acid molecule and
the antigen are administered within about 72 hours, about 48 hours,
about 24 hours, about 12 hours, about 8 hours, about 4 hours, about
2 hours, about 1 hour, or about 30 minutes or less, of each
other.
Immunostimulatory nucleic acid molecule may be administered
separately from antigen, in admixture with antigen, or the
immunostimulatory nucleic acid can be proximately associated with
(e.g., conjugated or brought into spatial proximation by other
means, as described in more detail below) one or more antigens (or
the antigen can be proximately associated with one or more
immunostimulatory nucleic acid molecules). Generally, and most
preferably, an immunomodulatory nucleic acid and an antigen are
proximately associated at a distance effective to enhance the
immune response generated compared to the administration of the ISS
and antigen as an admixture. For a detailed discussion of method
for proximate association of a polynucleotide and an antigen see,
e.g., PCT Publication WO 00/21556, incorporated herein by
reference.
In one embodiment, the immunostimulatory nucleic acid molecule and
the antigen are provided as conjugates. Particular conjugates which
may be useful in the methods of the present invention include
conjugates of an immunostimulatory nucleic acid molecule and a
polypeptide associated with a tumor; and conjugates of an
immunostimulatory nucleic acid molecule and a peptide associated
with an pathogenic organism.
The polypeptide may be a naturally-occurring polypeptide associated
with a tumor or with a pathogenic organism; or a synthetic analog
of a naturally-occurring polypeptide associated with a tumor or
with a pathogenic organism. A peptoid corresponding to a
naturally-occurring polypeptide associated with a tumor or with a
pathogenic organism. Peptoid compounds and methods for their
preparation are described in WO 91/19735.
Any of a variety of known tumor-specific antigens or
tumor-associated antigens (TAA) can be used in a conjugate with an
immunostimulatory nucleic acid molecule. The entire TAA may be, but
need not be, used. Instead, a portion of a TAA, e.g., an epitope,
may be used. Tumor-associated antigens (or epitope-containing
fragments thereof) which may be used into YFV include, but are not
limited to, MAGE-2, MAGE-3, MUC-1, MUC-2, HER-2, high molecular
weight melanoma-associated antigen MAA, GD2, carcinoembryonic
antigen (CEA), TAG-72, ovarian-associated antigens OV-TL3 and
MOV18, TUAN, alpha-feto protein (AFP), OFP, CA-125, CA-50, CA-19-9,
renal tumor-associated antigen G250, EGP-40 (also known as EpCAM),
S100 (malignant melanoma-associated antigen), p53, and p21ras. A
synthetic analog of any TAA (or epitope thereof), including any of
the foregoing, may be used. Furthermore, combinations of one or
more TAAs (or epitopes thereof) may be included in the conjugate.
For example, two or more TAA epitopes may be conjugated in tandem
to an immunostimulatory nucleic acid molecule, with or without an
intervening linker molecule.
Any of a variety of polypeptides associated with intracellular
pathogens may be used in a conjugate with an immunostimulatory
nucleic acid molecule. Polypeptides and peptide epitopes associated
with intracellular pathogens are any polypeptide associated with
(e.g., encoded by) an intracellular pathogen, fragments of which
are displayed together with MHC Class I molecule on the surface of
the infected cell such that they are recognized by, e.g., bound by
a T-cell antigen receptor on the surface of, a CD8.sup.+
lymphocyte. Polypeptides and peptide epitopes associated with
intracellular pathogens are known in the art and include, but are
not limited to, antigens associated with human immunodeficiency
virus, e.g., HIV gp120, or an antigenic fragment thereof;
cytomegalovirus antigens; Mycobacterium antigens (e g.,
Mycobacterium avium, Mycobacterium tuberculosis, and the like);
Pneumocystic carinii (PCP) antigens; malarial antigens, including,
but not limited to, antigens associated with Plasmodium falciparum
or any other malarial species, such as 41-3, AMA-1, CSP, PFEMP-1,
GBP-130, MSP-1, PFS-16, SERP, etc.; fungal antigens; yeast antigens
(e.g., an antigen of a Candida spp.); toxoplasma antigens,
including, but not limited to, antigens associated with Toxoplasma
gondii, Toxoplasma encephalitis, or any other Toxoplasma species;
Epstein-Barr virus (EBV) antigens; and the like.
A polypeptide may be conjugated directly or indirectly, e.g., via a
linker molecule, to an immunostimulatory nucleic acid molecule. A
wide variety of linker molecules are known in the art and can be
used in the conjugates. The linkage from the peptide to the
oligonucleotide may be through a peptide reactive side chain, or
the N- or C-terminus of the peptide. Linkage from the
oligonucleotide to the peptide may be at either the 3' or 5'
terminus, or internal. A linker may be an organic, inorganic, or
semi-organic molecule, and may be a polymer of an organic molecule,
an inorganic molecule, or a co-polymer comprising both inorganic
and organic molecules.
If present, the linker molecules are generally of sufficient length
to permit oligonucleotides and/or polynucleotides and a linked
polypeptide to allow some flexible movement between the
oligonucleotide and the polypeptide. The linker molecules are
generally about 6-50 atoms long. The linker molecules may also be,
for example, aryl acetylene, ethylene glycol oligomers containing
2-10 monomer units, diamines, diacids, amino acids, or combinations
thereof. Other linker molecules which can bind to oligonucleotides
may be used in light of this disclosure.
Peptides may be synthesized chemically or enzymatically, may be
produced recombinantly, may be isolated from a natural source, or a
combination of the foregoing. Peptides may be isolated from natural
sources using standard methods of protein purification known in the
art, including, but not limited to, HPLC, exclusion chromatography,
gel electrophoresis, affinity chromatography, or other purification
technique. One may employ solid phase peptide synthesis techniques,
where such techniques are known to those of skill in the art. See
Jones, The Chemical Synthesis of Peptides (Clarendon Press,
Oxford)(1994). Generally, in such methods a peptide is produced
through the sequential additional of activated monomeric units to a
solid phase bound growing peptide chain. Well-established
recombinant DNA techniques can be employed for production of
peptides.
Formulations
In general, immunostimulatory nucleic acid molecules are prepared
in a pharmaceutically acceptable composition for delivery to a
host. Pharmaceutically acceptable carriers preferred for use with
the immunostimulatory nucleic acid molecules of the invention may
include sterile aqueous of non-aqueous solutions, suspensions, and
emulsions. Examples of non-aqueous solvents are propylene glycol,
polyethylene glycol, vegetable oils such as olive oil, and
injectable organic esters such as ethyl oleate. Aqueous carriers
include water, alcoholic/ aqueous solutions, emulsions or
suspensions, and microparticles, including saline and buffered
media. Parenteral vehicles include sodium chloride solution,
Ringer's dextrose, dextrose and sodium chloride, lactated Ringer's
or fixed oils. Intravenous vehicles include fluid and nutrient
replenishers, electrolyte replenishers (such as those based on
Ringer's dextrose), and the like. A composition comprising a
immunostimulatory nucleic acid molecule may also be lyophilized
using means well known in the art, for subsequent reconstitution
and use according to the invention.
In general, the pharmaceutical compositions can be prepared in
various forms, such as granules, tablets, pills, suppositories,
capsules, suspensions, salves, lotions and the like. Pharmaceutical
grade organic or inorganic carriers and/or diluents suitable for
oral and topical use can be used to make up compositions comprising
the therapeutically-active compounds. Diluents known to the art
include aqueous media, vegetable and animal oils and fats.
Stabilizing agents, wetting and emulsifying agents, salts for
varying the osmotic pressure or buffers for securing an adequate pH
value, and skin penetration enhancers can be used as auxiliary
agents. Preservatives and other additives may also be present such
as, for example, antimicrobials, antioxidants, chelating agents,
and inert gases and the like. In one embodiment, as discussed
above, the immunostimulatory nucleic acid molecule formulation
comprises an additional anti-mycobacterial agent.
Immunostimulatory nucleic acid molecules can be administered in the
absence of agents or compounds that might facilitate uptake by
target cells (e.g., as a "naked" polynucleotide, e.g., a
polynucleotide that is not encapsulated by a viral particle, a
liposome, or any other macromolecule). Immunostimulatory nucleic
acid molecules can be administered with compounds that facilitate
uptake of immunostimulatory nucleic acid molecules by target cells
(e.g., by macrophages) or otherwise enhance transport of an
immunostimulatory nucleic acid molecule to a treatment site for
action. Absorption promoters, detergents and chemical irritants
(e.g., keratinolytic agents) can enhance transmission of an
immunostimulatory nucleic acid molecule composition into a target
tissue (e.g., through the skin). For general principles regarding
absorption promoters and detergents which have been used with
success in mucosal delivery of organic and peptide-based drugs,
see, e.g., Chien, Novel Drug Delivery Systems, Ch. 4 (Marcel
Dekker, 1992). Examples of suitable nasal absorption promoters in
particular are set forth at Chien, supra at Ch. 5, Tables 2 and 3;
milder agents are preferred. Suitable agents for use in the method
of this invention for mucosal/nasal delivery are also described in
Chang, et al., Nasal Drug Delivery, "Treatise on Controlled Drug
Delivery", Ch. 9 and Tables 3-4B thereof, (Marcel Dekker, 1992).
Suitable agents which are known to enhance absorption of drugs
through skin are described in Sloan, Use of Solubility Parameters
from Regular Solution Theory to Describe Partitioning-Driven
Processes, Ch. 5, "Prodrugs: Topical and Ocular Drug Delivery"
(Marcel Dekker, 1992), and at places elsewhere in the text. All of
these references are incorporated herein for the sole purpose of
illustrating the level of knowledge and skill in the art concerning
drug delivery techniques.
A colloidal dispersion system may be used for targeted delivery of
the immunostimulatory nucleic acid molecules to specific tissue.
Colloidal dispersion systems include macromolecule complexes,
nanocapsules, microspheres, beads, and lipid-based systems
including oil-in-water emulsions, micelles, mixed micelles, and
liposomes.
Liposomes are artificial membrane vesicles which are useful as
delivery vehicles in vitro and in vivo. It has been shown that
large unilamellar vesicles (LUV), which range in size from 0.2-4.0
Fm can encapsulate a substantial percentage of an aqueous buffer
comprising large macromolecules. RNA and DNA can be encapsulated
within the aqueous interior and be delivered to cells in a
biologically active form (Fraley, et al., (1981) Trends Biochem.
Sci., 6:77). The composition of the liposome is usually a
combination of phospholipids, particularly
high-phase-transition-temperature phospholipids, usually in
combination with steroids, especially cholesterol. Other
phospholipids or other lipids may also be used. The physical
characteristics of liposomes depend on pH, ionic strength, and the
presence of divalent cations. Examples of lipids useful in liposome
production include phosphatidyl compounds, such as
phosphatidylglycerol, phosphatidylcholine, phosphatidylserine,
phosphatidylethanolamine, sphingolipids, cerebrosides, and
gangliosides. Particularly useful are diacylphosphatidylglycerols,
where the lipid moiety contains from 14-18 carbon atoms,
particularly from 16-18 carbon atoms, and is saturated.
Illustrative phospholipids include egg phosphatidylcholine,
dipalmitoylphosphatidylcholine and
distearoylphosphatidylcholine.
Where desired, targeting of liposomes can be classified based on
anatomical and mechanistic factors. Anatomical classification is
based on the level of selectivity, for example, organ-specific,
cell-specific, and organelle-specific. Mechanistic targeting can be
distinguished based upon whether it is passive or active. Passive
targeting utilizes the natural tendency of liposomes to distribute
to cells of the reticulo-endothelial system (RES) in organs which
contain sinusoidal capillaries. Active targeting, on the other
hand, involves alteration of the liposome by coupling the liposome
to a specific ligand such as a monoclonal antibody, sugar,
glycolipid, or protein, or by changing the composition or size of
the liposome in order to achieve targeting to organs and cell types
other than the naturally occurring sites of localization.
The surface of the targeted delivery system may be modified in a
variety of ways. In the case of a liposomal targeted delivery
system, lipid groups can be incorporated into the lipid bilayer of
the liposome in order to maintain the targeting ligand in stable
association with the liposomal bilayer. Various well known linking
groups can be used for joining the lipid chains to the targeting
ligand (see, e.g., Yanagawa, et al., (1988) Nuc. Acids Symp. Ser.,
19:189; Grabarek, et al., (1990) Anal. Biochem., 185:131; Staros,
et al., (1986) Anal. Biochem. 156:220 and Boujrad, et al., (1993)
Proc. Natl. Acad. Sci. USA, 90:5728). Targeted delivery of
immunostimulatory nucleic acid molecules can also be achieved by
conjugation of the immunostimulatory nucleic acid molecules to a
the surface of viral and non-viral recombinant expression vectors,
to an antigen or other ligand, to a monoclonal antibody or to any
molecule which has the desired binding specificity.
An immunostimulatory nucleic acid molecule can be administered to
an individual in combination (e.g., in the same formulation or in
separate formulations) with another therapeutic agent ("combination
therapy"). The immunostimulatory nucleic acid molecule can be
administered in admixture with another therapeutic agent or can be
administered in a separate formulation. When administered in
separate formulations, an immunostimulatory nucleic acid molecule
and another therapeutic agent can be administered substantially
simultaneously (e.g., within about 60 minutes, about 50 minutes,
about 40 minutes, about 30 minutes, about 20 minutes, about 10
minutes, about 5 minutes, or about 1 minute of each other) or
separated in time by about 1 hour, about 2 hours, about 4 hours,
about 6 hours, about 10 hours, about 12 hours, about 24 hours,
about 36 hours, or about 72 hours, or more.
Therapeutic agents that can be administered in combination therapy,
such as anti-inflammatory, anti-viral, anti-fungal,
anti-mycobacterial, antibiotic, amoebicidal, trichomonocidal,
analgesic, anti-neoplastic, anti-hypertensives, anti-microbial
and/or steroid drugs, to treat antiviral infections. In some
embodiments, patients with a viral or bacterial infection are
treated with a combination of one or more immunostimulatory nucleic
acid molecules with one or more of the following; beta-lactam
antibiotics, tetracyclines, chloramphenicol, neomycin, gramicidin,
bacitracin, sulfonamides, nitrofurazone, nalidixic acid, cortisone,
hydrocortisone, betamethasone, dexamethasone, fluocortolone,
prednisolone, triamcinolone, indomethacin, sulindac, acyclovir,
amantadine, rimantadine, recombinant soluble CD4 (rsCD4),
anti-receptor antibodies (e.g., for rhinoviruses), nevirapine,
cidofovir (Vistide.TM.), trisodium phosphonoformate (Foscamet.TM.),
famcyclovir, pencyclovir, valacyclovir, nucleic acid/replication
inhibitors, interferon, zidovudine (AZT, Retrovir.TM.), didanosine
(dideoxyinosine, ddI, Videx.TM.), stavudine (d4T, Zerit.TM.),
zalcitabine (dideoxycytosine, ddC, Hivid.TM.), nevirapine
(Viramune.TM.), lamivudine (Epivir.TM., 3TC), protease inhibitors,
saquinavir (Invirase.TM., Fortovase.TM.), ritonavir (Norvir.TM.),
nelfinavir (Viracept.TM.), efavirenz (Sustiva.TM.), abacavir
(Ziagen.TM.), amprenavir (Agenerase.TM.) indinavir (Crixivan.TM.),
ganciclovir, AzDU, delavirdine (Rescriptor.TM.), kaletra, trizivir,
rifampin, clathiromycin, erythropoietin, colony stimulating factors
(G-CSF and GM-CSF), non-nucleoside reverse transcriptase
inhibitors, nucleoside inhibitors, adriamycin, fluorouracil,
methotrexate, asparaginase and combinations thereof.
Routes of Administration
Immunostimulatory nucleic acid molecules are administered to an
individual using any available method and route suitable for drug
delivery, including in vivo and ex vivo methods, as well as
systemic, mucosal, and localized routes of administration.
Conventional and pharmaceutically acceptable routes of
administration include intranasal, intramuscular, intratracheal,
intratumoral, subcutaneous, intradermal, topical application,
intravenous, rectal, nasal, oral and other parenteral routes of
administration. Routes of administration may be combined, if
desired, or adjusted depending upon the immunostimulatory nucleic
acid and/or the desired effect on the immune response. The
immunostimulatory nucleic acid composition can be administered in a
single dose or in multiple doses, and may encompass administration
of booster doses, to elicit and/or maintain the desired effect on
the immune response.
Immunostimulatory nucleic acid molecules can be administered to a
host using any available conventional methods and routes suitable
for delivery of conventional drugs, including systemic or localized
routes. In general, routes of administration contemplated by the
invention include, but are not necessarily limited to, enteral,
parenteral, or inhalational routes. Inhalational routes may be
preferred in cases of pulmonary involvement, particularly in view
of the activity of certain immunostimulatory nucleic acid molecules
as a mucosal adjuvant.
Inhalational routes of administration (e.g., intranasal,
intrapulmonary, and the like) are particularly useful in
stimulating an immune response for prevention or treatment of
infections of the respiratory tract. Such means include inhalation
of aerosol suspensions or insufflation of the polynucleotide
compositions of the invention. Nebulizer devices, metered dose
inhalers, and the like suitable for delivery of polynucleotide
compositions to the nasal mucosa, trachea and bronchioli are
well-known in the art and will therefore not be described in detail
here. For general review in regard to intranasal drug delivery,
see, e.g., Chien, Novel Drug Delivery Systems, Ch. 5 (Marcel
Dekker, 1992).
Parenteral routes of administration other than inhalation
administration include, but are not necessarily limited to,
topical, transdermal, subcutaneous, intramuscular, intraorbital,
intraspinal, intrastemal, and intravenous routes, i.e., any route
of administration other than through the alimentary canal.
Parenteral administration can be carried to effect systemic or
local delivery of immunostimulatory nucleic acid molecules.
Systemic administration typically involves intravenous,
intradermal, subcutaneous, or intramuscular administration or
systemically absorbed topical or mucosal administration of
pharmaceutical preparations. Mucosal administration includes
administration to the respiratory tissue, e.g., by inhalation,
nasal drops, ocular drop, etc.; anal or vaginal routes of
administration, e.g., by suppositories; and the like.
Immunostimulatory nucleic acid molecules can also be delivered to
the subject by enteral administration. Enteral routes of
administration include, but are not necessarily limited to, oral
and rectal (e.g., using a suppository) delivery.
Methods of administration of immunostimulatory nucleic acid
molecules through the skin or mucosa include, but are not
necessarily limited to, topical application of a suitable
pharmaceutical preparation, transdermal transmission, injection and
epidermal administration. For transdermal transmission, absorption
promoters or iontophoresis are suitable methods. For review
regarding such methods, those of ordinary skill in the art may wish
to consult Chien, supra at Ch. 7. Iontophoretic transmission may be
accomplished using commercially available "patches" which deliver
their product continuously via electric pulses through unbroken
skin for periods of several days or more. An exemplary patch
product for use in this method is the LECTRO PATCH.TM.
(manufactured by General Medical Company, Los Angeles, Calif.)
which electronically maintains reservoir electrodes at neutral pH
and can be adapted to provide dosages of differing concentrations,
to dose continuously and/or to dose periodically.
Epidermal administration can be accomplished by mechanically or
chemically irritating the outermost layer of the epidermis
sufficiently to provoke an immune response to the irritant. An
exemplary device for use in epidermal administration employs a
multiplicity of very narrow diameter, short tynes which can be used
to scratch immunostimulatory nucleic acid molecules coated onto the
tynes into the skin. The device included in the MONO-VACC.TM.
tuberculin test (manufactured by Pasteur Merieux, Lyon, France) is
suitable for use in epidermal administration of immunostimulatory
nucleic acid molecules.
The invention also contemplates opthalmic administration of
immunostimulatory nucleic acid molecules, which generally involves
invasive or topical application of a pharmaceutical preparation to
the eye. Eye drops, topical cremes and injectable liquids are all
examples of suitable formulations for delivering drugs to the
eye.
Dosages
Although the dosage used will vary depending on the clinical goals
to be achieved, a suitable dosage range is one which provides up to
about 1 .mu.g to about 1,000 .mu.g or about 10,000 .mu.g of
immunostimulatory nucleic acid molecule can be administered in a
single dosage. Alternatively, a target dosage of immunostimulatory
nucleic acid molecule can be considered to be about 1-10 .mu.M in a
sample of host blood drawn within the first 24-48 hours after
administration of immunostimulatory nucleic acid molecules. Based
on current studies, immunostimulatory nucleic acid molecules are
believed to have little or no toxicity at these dosage levels.
It should be noted that the immunotherapeutic activity of
immunostimulatory nucleic acid molecules is generally
dose-dependent. Therefore, to increase immunostimulatory nucleic
acid molecules potency by a magnitude of two, each single dose is
doubled in concentration. Increased dosages may be needed to
achieve the desired therapeutic goal. The invention thus
contemplates administration of "booster" doses to provide and
maintain a desired immune response. For example, immunostimulatory
nucleic acid molecules may be administered at intervals ranging
from at least every two weeks to every four weeks (e.g., monthly
intervals) (e.g., every four weeks).
EXAMPLES
The following examples are put forth so as to provide those of
ordinary skill in the art with a complete disclosure and
description of how to make and use the present invention, and are
not intended to limit the scope of what the inventors regard as
their invention nor are they intended to represent that the
experiments below are all or the only experiments performed.
Efforts have been made to ensure accuracy with respect to numbers
used (e.g. amounts, temperature, etc.) but some experimental errors
and deviations should be accounted for. Unless indicated otherwise,
parts are parts by weight, molecular weight is weight average
molecular weight, temperature is in degrees Celsius, and pressure
is at or near atmospheric.
Example 1
Conjugates of OVA and an Immunostimulatory Nucleic Acid Molecule
Induce High Antigen-specific CTL Activity
Methods
Protein immunostimulatory sequence oligonucleotide (ISS-ODN) (PIC)
conjugate synthesis
All chemicals were purchased from Sigma (St. Louis, Mo.) unless
otherwise noted. Ovalbumin (chicken egg albumin, Grade VI) was
activated with 20-fold molar excess of
sulfosuccinimidyl-4-(N-maleimidomethyl)
cyclohexane-1-carboxylate(sulfo-SMCC, Pierce, Rockford, Ill.) at
room temperature for one hour. This modified the amino side chains
of L-lysine residues by the addition of maleimide groups. Residual
reagents were removed by chromatography on a G-25 desalting column
(Amersham Pharmacia Biotech, Piscataway, N.J.).
5'-disulfide-ISS-ODN were reduced with 200 mM TRIS (2-carboxyethyl)
phosphine (TCEP, Pierce) at room temperature for one hour, and
residual reagents were removed by chromatography on a G-25
desalting column. The resulting 5'-thio-ISS-ODN were mixed with the
modified OVA at a 5:1 molar ratio (ISS-ODN:OVA) and incubated
overnight at room temperature. 5' Disulfide-linked phosphorothioate
ISS-ODN, sequence 5'-disulfide-TGACTGTGAACGTTCGAGATGA-3' (SEQ ID
NO:1) and mutated ODN, sequence
5'-disulfide-TGACTGTGAACCTTCGAGATGA-3' (SEQ ID NO:2) were purchased
from Tri-Link Biotechnology (San Diego, Calif.). Non-reducing
SDS-PAGE was performed using Novex (San Diego, Calif.) 10-20%
Tricine mini-gels run at a constant voltage of 100 V. Protein
concentration was determined by Bradford assay (Bio-Rad, Hercules,
Calif.). PIC samples were determined to be LPS-free by Limulus
amebocyte lysate assay (BioWhittaker, Walkersville, Md.).
Vaccines
Single stranded phosphorothioate ISS-ODN, sequence 5'-TGACTGTGAACGT
TCGAGATGA-3' (SEQ ID NO:3) were purchased from Tri-Link
Biotechnology. Plasmid pACB-OVA was as described. Corr et al.
(1997) J. Immunol. 159:4999-5004; and Raz et al. (1996) Proc. Natl.
Acad. Sci. USA 93:5141-5145.
Peptides
H-2.sup.b MHC class I-restricted peptides were purchased from
Peptido Genics Research (Fullerton, Calif.). OVA peptide: NH.sub.2
-SIINFEKL-COOH (SEQ ID NO:4). Influenza virus nucleoprotein (NP)
peptide (negative control): NH.sub.2 -ASNENMETM-COOH (SEQ ID
NO:5).
CTL Assay
The CTL assay was conducted as follows. Briefly, 2.times.10.sup.6
effector splenocytes were restimulated in culture for five days
with 1.8.times.10.sup.7 OVA peptide-pulsed stimulator splenocytes
and 50 U/ ml recombinant human IL-2 (PharMingen) in RPMI culture
medium (Irvine Scientific, Santa Ana, Calif.) supplemented with 10%
heatBinactivated fetal calf serum (FCS), 50 mM
.beta.-mercaptoethanol (Sigma), 2 mM L-glutamine, 100 U/ ml
penicillin, and 100 .mu.g/ ml streptomycin (RP 10). After
restimulation, viable lymphocytes were recovered by centrifugation
over Ficoll lympholyte M (Cedarlane Laboratories, Ltd., Ontario,
Canada) at room temperature for 20 minutes. Cells were washed once
in RP2 (RPMI+2% FCS) and then serially-diluted to several effector
to target cell ratios (E:T) in 96-well U-bottom culture plates
(Costar, Cambridge, Mass.) in colorless RPMI (Irvine Scientific)
supplemented with 2% bovine serum albumin (Sigma), 2 mM
L-glutamine, 100 U/ml penicillin, and 100 .mu.g/ml streptomycin.
Target EL4 cells were pulsed with OVA or NP peptide at 37.degree.
C. for one hour, then washed three times with colorless RPMI.
Plates were incubated for 4 hours, and supernatants recovered.
Specific lysis was assayed with the CytoTox 96 kit (Promega,
Madison, Wis.) according to the manufacturer's instructions.
Results
Synthesis of OVA-ISS Conjugates
Hen egg ovalbumin (OVA) was used as a model antigen in the series
of experiments described herein. The OVA-ISS-conjugates were
prepared as described above. PIC was qualitatively evaluated by
non-reducing sodium dodecyl sulfate-polyacrylamide gel
electrophoresis (SDS-PAGE). Bands corresponding to PIC were
visualized by short-wave UV shadowing on a silica gel thin layer
chromatography plate, followed by Coomassie G-250 staining to
detect protein bands. A ladder is visible corresponding to
increasing ISS-ODN:OVA ratios in the conjugate. PIC at ISS-ODN:OVA
ratios higher than 1:1 stain poorly with Coomassie blue due to the
high concentration of acidic ODN. The average molar ratio of
ISS-ODN:OVA in this series of experiments was .about.2.4:1.
Conjugate was also synthesized with mutated ODN that do not contain
CpG dinucleotides, and this mutated PIC (designated "mPIC") was
used as a control.
PIC Vaccination Induces High Antigen-specific CTL Activity
To determine if PIC is more efficient than co-administration of OVA
and ISS-ODN or plasmid DNA vaccine, wild type (wt) C57B1/6 mice
were immunized with PIC and the resultant CTL activity was
evaluated. For comparison, test groups were immunized with mPIC,
OVA+ISS-ODN co-administration, pACB-OVA (a plasmid DNA vaccine that
contains ISS motifs), and OVA alone. An untreated group was also
included. In secondary CTL assays, PIC vaccination resulted in
remarkably high activity, with 91.+-.5% specific lysis observed at
a 25:1 effector to target (E:T) ratio and 92.+-.4% at a 1:1 ratio,
indicating that activity was at a plateau even at a high
dilution.
These results are shown in FIG. 1. Test animals were immunized
intradermally (i.d.) at the tail base on days zero and 14 with the
following vaccines: PIC (50 .mu.g, closed square), OVA+ISS-ODN
co-administration (50 .mu.gg each, closed diamond), mPIC (50 .mu.g,
open diamond), pACB-OVA (50 .mu.g, closed circle), or OVA alone (50
.mu.g, closed triangle). Vaccines were diluted in sterile normal
saline solution. At six weeks, total splenocytes were isolated and
restimulated in culture for five days. Secondary CTL activity was
determined by LDH release. Targets were EL-4 cells loaded with
either MHC class I-restricted OVA peptide or influenza virus
nucleoprotein peptide (target control, open square). Error bars
indicate the standard error of the mean. Data are averaged from
four to five mice per group, and are representative of four
experiments.
At a 0.2:1 E:T ratio, specific lysis was 64.+-.10%. This activity
was significantly higher than that observed in OVA+ISS
co-administration, despite the higher molar ratio of ISS-ODN:OVA
protein in the latter treatment (6:1 in the co-administration vs.
.about.2.4:1 in the PIC).
PIC also elicited higher levels of CTL activity than pACB-OVA
vaccination. Animals immunized with mPIC exhibited low CTL activity
(33.+-.2% specific lysis at 25:1 ratio), which is comparable to the
non-specific adjuvant activity of mutated oligonucleotide. OVA
administration alone did not stimulate CTL activity. Target cells
loaded with an irrelevant MHC class I-restricted peptide were not
lysed by splenocytes from OVA PIC-immunized mice, indicating that
the observed response was antigen-specific. These results show that
vaccination with PIC resulted in higher antigen-specific CTL
activity than other ISS-based vaccines.
Example 2
Conjugates of OVA and an Immunostimulatory Nucleic Acid Molecule
Induces a Th1-like Response
Methods
Cytokine ELISA
Purified rat anti-mouse IFN.gamma. capture antibody and purified,
biotinylated rat anti-mouse IFN.sub..gamma. detecting antibody were
purchased from PharMingen (San Diego, Calif.). IL-4 capture and
detecting antibodies (Duoset) were purchased from Genzyme
(Cambridge, Mass.). Briefly, splenocytes were isolated as described
in the previous section, and 5.times.10.sup.5 splenocytes were
aliquoted in triplicate into 96 well culture plates (Costar) in a
total volume of 200 .mu.l RP10 with and without 50 .mu.g/ml
ovalbumin (Sigma). Cultures were incubated at 37.degree. C. with 5%
CO.sub.2 for three days, and then aliquots of tissue culture
supernatant were removed for cytokine ELISA. Half-area 96 well
plates (Costar) were coated with capture antibody diluted 1:1000 in
carbonate buffer (15 mM Na.sub.2 CO.sub.3, 35 mM NaHCO.sub.3, pH
9.6), overnight at 4.degree. C. Plates were washed with 1.times.BBS
(160 mM NaCl, 40 mM NaOH, 200 mM Boric acid, pH 8.0) and then
blocked for two hours at 37.degree. C. with blocking buffer (1% BSA
in BBS). Plates were washed and incubated with tissue culture
supernates diluted 1:2 in blocking buffer overnight at 4.degree. C.
Plates were washed and incubated with detecting antibody diluted
1:1000 in blocking buffer at room temperature for one hour. Plates
were washed and incubated with streptavidin-HRP conjugate (Zymed,
South San Francisco, Calif.) diluted 1:2000 in blocking buffer at
room temperature for one hour. Plates were washed and incubated
with TMB substrate (Moss, Incorporated, Hanover, Md.). The reaction
was stopped with 1M phosphoric acid (Sigma) and the plates were
read at 450 nm on a Molecular Devices ThermoMax microplate reader
(Sunnyvale, Calif.).
Ig ELISA
Alkaline phosphatase-conjugated goat anti-mouse IgG.sub.1 and
IgG.sub.2a were purchased from Southern Biotechnology Associates
(Birmingham, Ala.). Plates were coated with serum serially diluted
in blocking buffer overnight at 4.degree. C. Plates were washed and
incubated with detecting antibody diluted 1:2000 in blocking
buffer. Plates were washed and incubated with 4-nitrophenyl
phosphate substrate (Roche Diagnostics, Basel, Switzerland). Plates
were read at 405 nm as described above.
Results
PIC Vaccination Induces a T.sub.h 1-like Immune Response
Total splenocyte cytokine production and antigen-specific isotype
switching to IgG.sub.2a were examined to assess the T helper
response to PIC vaccination. Splenocytes from the groups described
in the previous section were re-stimulated in culture, and tissue
culture supernatants were collected at day 3 for cytokine ELISA.
PIC and OVA+ISS-ODN co-administration induced comparable levels
(3800.+-.1800 and 3600.+-.1100 pg/ml, respectively) of IFN.gamma.,
a Th1-associated cytokine, in response to OVA stimulation. The
results are shown in FIG. 2A. By comparison, pACB-OVA and mPIC
vaccination resulted in IFN.sub..gamma. production approximately
20% and 10% of this amount, respectively. IL-4, a Th2-associated
cytokine, was not detected in any of the groups.
IFN.gamma. is a switch factor for IgG2a, and isotype switching to
IgG2a is also a marker for Th1-biased immune responses. Serum was
collected at week 6 and assayed for OVA-specific IgG.sub.1 and
IgG.sub.2a by immunoglobulin ELISA. The results are shown in FIGS.
3B and 3C. PIC induced a substantial isotype switch to IgG.sub.2a,
similar to co-administration of OVA+ISS-ODN. PIC vaccination also
produced a higher titer of IgG.sub.1 +IgG.sub.2a, suggesting that
the magnitude of the T.sub.h and concomitant B cell response was
higher. Immunization with mPIC resulted in antigen-specific
IgG.sub.1 production without isotype switching to IgG.sub.2a. These
data indicate that PIC vaccination promoted a T.sub.h 1-like helper
phenotype as measured by IFN.sub..gamma. production and IgG.sub.2a
isotype switching.
Total splenocytes were isolated as described in Example 1.
Splenocytes were restimulated as described above, and IFN.gamma.
concentration in day three supernatants was determined by cytokine
ELISA. Values for IFN.gamma. concentration are shown in FIG. 2A.
IgG.sub.1 and IgG.sub.2a titers in week six serum from immunized
mice are shown in FIGS. 2B and 2C, respectively. Relative titer was
determined by isotype-specific ELISA. Error bars indicate the
standard error of the mean. Data are averaged from four to five
mice per group, and are representative of four experiments.
Example 3
Induction of CTL Activity by a Conjugate of OVA and an
Immunostimulatory Nucleic Acid Molecule is Independent of MHC Class
II-restricted T Cell Help
Results
Induction of CTL Activity by PIC is Independent of MHC Class
II-restricted Help
To test the hypothesis that CTL induction and T.sub.h 1-bias are
independent in PIC vaccination, CD4.sup.-/- and MHC class
II.sup.-/- gene-deficient mice were vaccinated according to the
protocol described in Example 1. MHC class II.sup.-/- mice were
included to assess the contribution of MHC class II-restricted T
cell help by CD4.sup.- /CD8.sup.- lymphocytes. The CTL responses of
wt mice to PIC, OVA and ISS-ODN co-administration, and OVA alone
are shown in FIG. 3A. Vaccination with either PIC or OVA+ISS-ODN
elicited high antigen-specific CTL activity (61.+-.3% and 54.+-.2%
specific lysis at a 25:1 E:T ratio, respectively) from CD4.sup.-/-
mice, as shown in FIG. 3B. These vaccines also stimulated CTL
activity (83.+-.3% and 65.+-.4% specific lysis, respectively) from
MHC class II.sup.-/- mice, as shown in FIG. 3C. OVA alone did not
elicit CTL activity in these groups. Plasmid pACB-OVA did not
stimulate antigen-specific CTL activity in CD4.sup.-/- mice.
Neither CD4.sup.-/- nor MHC class II.sup.-/- mice generated a
T.sub.h 1-biased immune response to PIC vaccination as measured by
IFN.sub..gamma. and IgG.sub.2a production. Therefore, activation of
CTL activity by ISS adjuvant was independent of MHC class
II-restricted T cell help. Interestingly, effector function from
CD4.sup.-/- and MHC class II.sup.-/- mice immunized with
OVA+ISS-ODN was more rapidly diluted at 5:1 and 1:1 E:T ratios
compared to PIC vaccination, suggesting that co-administration was
less efficient than PIC under conditions where T cell help was not
available.
FIGS. 3A-C show the results of the above-described experiments
performed in wild type (FIG. 3A), CD4.sup.-/- (FIG. 3B), and MHC
class II.sup.-/- (FIG. 3C) gene-deficient animals. Animals were
vaccinated i.d. at the tail base on days zero and 14 with either
PIC (50 .mu.g, square), OVA+ISS-ODN (50 .mu.g each, diamond), or
OVA alone (50 .mu.g, circle). CTL activity was determined as
described in Example 1. Error bars indicate the standard error of
the mean. Data are averaged from four mice per group, and are
representative of two experiments.
Example 4
Vaccination with a Conjugate of OVA and an Immunostimulatory
Nucleic Acid Molecule Results in Protective Immunity in Both
Preventive and Therapeutic Models of Cancer
Results
Vaccination with PIC Results in Protective Immunity in Mouse Models
of Cancer
To assess the in vivo effectiveness of PIC vaccination, two mouse
models of cancer were examined. In a preventive model of tumor
vaccination, C57B1/6 mice were vaccinated with PIC and other
ISS-based vaccines, as well as controls. The test animals were
vaccinated twice, then received a lethal tumor challenge of
E.G7-OVA or EL-4 cells, and tumor growth was followed for six
weeks. Porgador et al. (1996). J. Immunol. 156:2918-2926.
Vaccination with PIC suppressed tumor growth, as shown in FIG. 4A.
Vaccination with pACB-OVA also inhibited tumor growth, but to a
lesser degree. OVA+ISS-ODN initially appeared to slow growth of
tumor, but at later time points, this effect was reduced. Neither
ISS-ODN nor OVA protein alone appeared to significantly retard
tumor growth. Similarly, vaccination with mPIC, which does not
contain CpG dinucleotides, did not confer protection. Immunization
with ISS-based vaccines did not prevent the growth of EL-4 cells,
the parental line that does not express OVA, indicating that the
protective effect was antigen-specific. Treatment with ISS-based
vaccines also did not appear to affect overall survival, in that
there was no evidence of increased, non-tumor-related morbidity or
mortality among groups that demonstrated tumor immunity over the
susceptible groups.
PIC appeared to be the most effective vaccine for stimulating
resistance to tumor growth in the preventive model, so it was also
tested in a therapeutic model of cancer. Test animals received
tumor challenge on day zero, and were subsequently immunized either
on days zero, 6, and 11 (early), or on days 6, 11, and 15 (late).
Early vaccination with PIC resulted in profound suppression of
tumor growth relative to controls, as shown in FIG. 4B. Late
vaccination with PIC induced tumor regression by 14 days, with
subsequent suppression of tumor growth. These results showed that
vaccination with PIC resulted in protective immunity against tumor
expressing OVA in both preventive and therapeutic models of
cancer.
Preventive model (FIG. 4A). Test animals were vaccinated i.d. at
the tail base on days zero and 14 with the following vaccines: PIC
(50 .mu.g, closed square), mPIC (50 .mu.g, open square),
OVA+ISS-ODN co-administration (50 .mu.g each, closed diamond),
pACB-OVA (50 .mu.g, closed triangle), or OVA alone (50 .mu.g,
closed circle). On day 28, each group received a lethal challenge
of 20.times.10.sup.6 E.G7-OVA cells sub-cutaneously (s.c.) in the
right flank, and tumor growth was followed over the subsequent six
weeks. The observed difference in tumor growth is statistically
significant between the PIC and mPIC groups (two-tailed t test,
p=0.05), PIC and OVA alone (p<0.02), and PIC and no treatment
(p<0.025).
Therapeutic model (FIG. 4B). Test animals received s.c. tumor
challenge on day zero and early (days zero, 6, and 11, open square)
or late (days 6, 11, and 15, closed square) i.d. vaccination with
PIC (50 .mu.g). The observed difference in tumor growth between the
PIC treatment groups and untreated controls is statistically
significant (p<0.005).
PIC-induced Anti-tumor Immunity is Dependent on CD8.sup.+ CTL and
Independent of CD4.sup.+ Cell Help
PIC efficiently promotes CTL activity and T.sub.h 1-biased immune
responses. To assess the roles of CD8.sup.+ CTL activity and
CD4.sup.+ T.sub.h -dependent mechanisms in anti-tumor immunity,
CD4.sup.-/- and CD8.sup.-/- gene-deficient mice received
subcutaneous tumor challenge on day zero and were immunized with
PIC on days zero, 3, and 7. CD4.sup.-/- and wt control animals
exhibited similar suppression of tumor growth, whereas CD8.sup.-/-
mice did not suppress tumor growth, as shown in FIG. 4C. As
expected, CD4.sup.-/- animals did not exhibit a T.sub.h 1-biased
immune response, while CD8.sup.-/- mice had a response similar to
wt animals. These results showed that protective anti-tumor
immunity induced by PIC is mediated by CD8.sup.+ CTL activity,
rather than T.sub.h -dependent mechanisms.
Therapeutic model in CD4.sup.-/- (closed square) and CD8.sup.-/-
(open square) gene-deficient mice (FIG. 4C). Gene-deficient animals
received s.c. tumor challenge on day zero and were immunized i.d.
with PIC (50 .mu.g) on days zero, 3, and 7. The observed difference
in tumor growth between CD4.sup.-/- and CD8.sup.-/- groups is
statistically significant (p<0.005). Tumor growth in all three
plots is expressed as tumor index=square root (length.times.width).
Data are averaged from six mice per group and are representative of
two experiments each.
Example 5
Characterization of the Requirements for ISS-mediated Activation of
CTL
Protocols
Mice were vaccinated with ISS+OVA as described in Example 1. CTL
assays were conducted, as described in Example 1.
Bone marrow chimeras were created using a standard protocol.
Briefly, femurs were harvested from TAP-/- and C57BL/6 wt donors.
Bone marrow was flushed out, and a single-cell suspension in cell
culture medium was made. After allowing debris to settle, the top
layer of the suspension was transferred to a fresh tube. Cells were
subsequently treated with anti-Thy1, anti-CD4, and anti-CD8
antibodies plus complement. The final cell culture was pelleted,
the re-suspended in cell culture medium at about 10.sup.8
cells/ml.
Results
ISS-based Vaccines Require TAP Activity for Priming of CTL
Transporters associated with Antigen Processing (TAP) are
heterodimeric proteins associated with the endoplasmic reticulum
membrane, and are required for antigen presentation by MHC Class I
molecules.
Bone marrow from TAP.sup.-/- mice were introduced into wild type
mice to create chimeras. The TAP.fwdarw.wt bone marrow chimeras
were vaccinated, and CTL assays were conducted. As shown in FIG. 5,
TAP.fwdarw.wt chimeras failed to generate antigen-specific CTL,
whereas wt.fwdarw.wt chimeras did generate antigen-specific CTL,
demonstrating that TAP is required for cross-presentation promoted
by ISS+OVA immunization.
CD40 Signaling is not Essential for ISS-mediated CTL Activation
CD40 is a molecule found on the surface of activated macrophages
and B cells, and interacts with CD40 ligand, which is expressed on
the surface of effector T cells. Current models of cross-priming to
soluble protein antigens suggest that APC require an initial
"licensing" interaction with Th cells before they can prime naive
CTL, and this interaction requires CD40 signaling.
CD40.sup.-/- mice, CD40 ligand.sup.-/- mice, and wild-type mice
pre-treated with anti-CD40 ligand antibody were vaccinated as
described in Example 1. As shown in FIG. 6, wt mice immunized with
ISS+OVA demonstrated antigen-specific CTL activity of 80.+-.2%
specific lysis at a 25:1 effector:target (E:T) ratio. Lytic
activity from splenocytes of CD40-/- mice (68.+-.2% at 25:1 E:T)
and wt mice pre-treated with anti-CD40L monoclonal antibody (mAb)
(78.+-.7% at 25:1 E:T ratio) did not differ significantly from that
of untreated wt mice. Thus, in contrast to current models for
cross-priming to soluble protein antigens, CD40 signaling is not
essential for direct activation of CTL by ISS-based vaccines.
Activation of CTL by ISS Vaccine Requires B7-CD28 Signaling
Effector T cells are activated when their antigen-specific
receptors and either the CD4 or CD8 co-receptors bind to
peptide:MHC complexes. However, stimulation of naive T cells to
proliferate and differentiate into armed effector T cells requires
a co-stimulatory signal. Binding of a B7 molecule on the surface of
an APC to a CD28 molecule on the surface of T cells is an example
of molecular interaction which provides the required co-stimulatory
signal.
Wild-type mice were pre-treated with blocking antibodies to the
co-stimulatory molecules B7-1 and -2, then vaccinated as described
in Example 1. CD28.sup.-/- mice were vaccinated as described in
Example 1. As shown in FIG. 7, vaccination of wild-type mice
pre-treated with blocking antibodies to B7-1 and B7-2, or
vaccination of CD28.sup.-/- mice, resulted in a 52-80% reduction in
CTL activity, compared to wild-type mice. These data indicate that
the co-stimulatory signal provided by the B7-1/-2-CD28 interaction
is required for ISS-mediated CTL activation.
Addition of anti-CD40 ligand (anti-CD40L) to the
anti-B7-1/-2-treated mice, or to the CD28.sup.-/- mice had no
effect on CTL activation, supporting the above conclusion that
CD40/CD40-ligand interactions are not essential for ISS-mediated
CTL activation.
IL-12 Contributes to ISS-mediated Priming of CTL
IL-12 is a pro-inflammatory cytokine produced by activated
macrophages and other APC, and has been shown to promote priming of
CTL.
IL-12.sup.-/- mice, wild-type mice, and IL-12.sup.-/- mice
pre-treated with anti-B7-1/-2 antibody were vaccinated as described
in Example 1. As shown in FIG. 8, IL-12.sup.-/- mice showed an 35%
reduction in CTL activation, while IL-12.sup.-/- mice pre-treated
with anti-B7-1/-2 antibody showed a 70% reduction in CTL
activation, compared to wild-type mice. These data indicate that
IL-12 contributes to ISS-mediated priming of CTL, but does not
synergize with B7 signaling at the activation step.
The above results indicate that ISS-based vaccines bypass T cell
help in this system by providing both co-stimulation and
cross-presentation.
Example 6
Induction of Chemokines by Immunostimulatory Sequences (ISS)
Bone marrow derived macrophages (BMDM) were obtained from femurs of
BALB/c mice and grown in tissue culture for one week. After one
week in culture, BMDM were stimulated with ISS (1 .mu.g/ml), M-ODN
(control-ODN, 1 .mu./ml), or lipopolysaccharide (LPS) (10
.mu.g/ml). ISS has the sequence 5'-TGACTGTGAACGTTCGAGATGAB3' (SEQ
ID NO:3); and mutated, control ODN )M-ODN) has the sequence
5'-TGACTGTGAACCTTCGAGATGAB3' (SEQ ID NO:6).
Twenty-four hours after stimulation, supernatants were collected
and chemokine levels were detected and measured using an
enzyme-linked immunosorbent assay (ELISA) from Pharmingen. The
results are shown in Table 1, below.
TABLE 1 MIP-1.alpha. MIP-1.beta. RANTES (pg/ml) (pg/ml) (pg/ml)
Media <100 <200 <2 LPS 310 .+-. 55 2810 .+-. 210 21 .+-. 5
ISS-ODN (1 .mu.g) 4222 .+-. 350 4560 .+-. 1230 20 .+-. 8 M-ODN (1
.mu.g) <100 <200 <2
The data presented in Table 1 show that BMDM from BALB/c mice
exposed in culture to ISS secrete high levels of MIP-1.alpha. and
MIP-1.beta., and lower levels of RANTES. The level of MIP-1.alpha.
and MIP-1.beta. secretion exceeded that from lipopolysaccharide
(LPS)-treated BMDM. The level of RANTES secretion from
ISS-LPS-treated BMDM was about the same. A mutant oligonucleotide
lacking a critical CpG motif did not stimulate secretion of any of
the chemokines tested.
Example 7
Induction of a gp120-specific Chemokine Response
Female BALB/c mice aged 4-6 weeks were immunized with gp120 (10
.mu.g) alone, with gp120 with ISS (50 .mu.g), or M-ODN (50 .mu.g),
or with gp120:ISS conjugate (10 .mu.g based on gp120 content).
Immunizations were given by either an intradermal (i.d.) or
intranasal (i.n.) routes on 3 occasions spaced 2 weeks apart. Mice
were sacrificed and splenocytes were isolated by routine methods at
week 12. Gp120-specific chemokine responses by CD4.sup.+ cells were
evaluated by incubation of 5.times.10.sup.5 splenocytes in 96-well
plates in a final volume of 200 .mu.l of RPMI 1640 supplemented
with gp120 at 10 .mu.g/ml. In control cultures, splenocytes were
incubated in RPMI 1640 without added gp120. Culture supernatants
were harvested at 72 hours and analyzed by ELISA. The data are
shown in FIGS. 9-11. MIP1.alpha., MIP1.beta., and RANTES were
detected at the indicated levels in supernatants of splenocytes
isolated from mice administered with ISS mixed with gp120, or in
supernatants of splenocytes from mice administered with ISS:gp120
conjugates, when the isolated splenocytes were cultured in the
presence of gp120. Only very low levels of MIP1.alpha., MIP1.beta.,
and RANTES could be detected in splenocytes isolated from mice
administered with gp120 alone, or from mice administered with gp120
mixed with M-ODN. Neither MIP1.alpha., MIP1.beta., nor RANTES was
detected in supernatants of splenocytes cultured in the absence of
gp120. The data demonstrate that splenocytes derived from mice
immunized with ISS and gp120 (either as a mixture or as a
conjugate) and cultured with gp120 produce CCR5-binding chemokines
MIP1.alpha., MIP1.beta., and RANTES in a gp120-specific manner. In
contrast to the gp120-specific, CCR5 binding chemokine response
(i.e., MIP1.alpha., MIP1.beta., and RANTES) presented in FIGS.
9-11, the stem cell-derived factor-1 (SCF-1; a CXCR4-binding
chemokine) was not produced by splenocytes cultured with gp120.
Example 8
Immunostimulatory DNA-based Vaccines Elicit Multi-faceted Immune
Responses Against HIV at Systemic and Mucosal Sites
Materials and Methods
Reagents: HIV gp120 protein was obtained from Quality Biological,
Inc. (Gaithersburg, Md.). ISS and mutated phosphorothioate
oligodeoxynucleotides (mODN) were purchased from Trilink
Biotechnologies (San Diego, Calif.). The sequence of the ISS used
in these studies is 5'-TGACTGTGAACGTTCGAGATGA-3' (SEQ ID NO:3). The
mODN has the sequence 5'-TGACTGTGAACCTTAGAGATGA-3' (SEQ ID NO:7).
gp120:ISS and gp120:mODN conjugates were produced in a three-step
process as previously described. Cho et al. (2000) Nat. Biotech.
18:509-514; and Gallucci et al. (1999) Nat. Med. 5:1249-1255.
Introduction of maleimido groups onto gp120 molecules was achieved
by incubation with a 20 molar excess of sulfo-SMCC
(sulfosuccinimidyl 4-(N-maleimidomethyl)-cyclohexane-1-carboxylate)
(Pierce Chemicals, Rockford, Ill.) for 2 hours followed by
purification on a NAP-25 Column (Amersham-Pharmacia, Uppsala,
Sweden). 5' activation of oligodeoxynucleotides was carried out by
incubation with 0.2M TCEP (tricarboxyethylphosphine, Pierce
Chemicals) and activated oligodeoxynucleotides were subsequently
purified on a NAP-10 column. Maleimido-modified gp120 and
thiol-activated oligodeoxynucleotides were then incubated together
overnight, and free oligodeoxynucleotides were removed by
filtration using an Amicon-50 spin column (Amicon, Inc., Beverly,
Mass.). The conjugate was analyzed by SDS-PAGE. After
electrophoresis, the samples were transferred onto nitrocellulose
membranes and visualized by chemiluminescent detection of
anti-gp120 antibody (Western blotting) or by autoradiography after
hybridization with complementary .sup.32 P-.gamma.-ATP-labeled
oligodeoxynucleotides (Southwestern blotting).
Immunization protocols: Female BALB/c mice (Jackson Laboratories,
Bar Harbor, Me.) aged 4-6 weeks were immunized with gp120 (10
.mu.g) alone or with ISS (50 .mu.g) or mODN (50 .mu.g).
Alternatively, mice were vaccinated with gp120:ISS or gp120:mODN
conjugate (10 .mu.g based on gp120 content). For intradermal (i.d.)
immunization, reagents were delivered in 50 .mu.l of saline by
injection into the base of the tail. For intranasal (i.n.)
vaccination, reagents were applied topically in 30 .mu.l of saline
divided equally and delivered to each nare of lightly anesthetized
mice. Immunizations were delivered on 3 occasions spaced 2 weeks
apart. For CD4 T cell depletion, mice received 1 mg of GK 1.5 mAb
(Bio Express, West Lebanon, N.H.) intraperitoneally (i.p.) on 3
occasions, 4 weeks apart. With the use of flow cytometry, we
determined that mice receiving GK 1.5 mAb, had <1% of the
peripheral blood and splenic CD4 T cell counts of untreated mice
throughout the course of these experiments. All animal procedures
followed UCSD's animal care guidelines.
Sample collection and processing: Serum was obtained by
retro-orbital bleeds during week 12. Vaginal washes were obtained
during week 12 by lavage with 50 .mu.L of PBS. Samples were spun to
remove cellular debris, and frozen at -70.degree. C. until the IgA
assay was performed. Feces were collected at week 12 and IgA
extracted by routine methods. Briefly, 3-6 pieces of freshly voided
feces were collected and subsequently dried in a Speed Vac
Concentrator. After drying, net dry weights were recorded, and the
material was resuspended in PBS with 5% nonfat dry milk and
protease inhibitors at a ratio of 20 .mu.L/mg of feces to
standardize for variability in the amount of fecal material
collected. The solid matter was resuspended by vortexing for 12
hours followed by centrifugation at 16,000.times.g for 10 minutes
to separate residual solids from supernatant. Supernatants were
frozen at -70 C. until the IgA assay was performed.
Splenocytes (1.times.10.sup.8 /mouse), Peyer's patch lymphocytes
(1.times.10.sup.7 /mouse), and lamina propria lymphocytes
(1.5.times.10.sup.6 /moue) were recovered 12 weeks after the
initiation of immunization, by routine methods. Briefly, spleens
were harvested and teased to make single cell suspensions.
Intestines were isolated, stripped of mesenteric fat, and Peyer's
patches excised. The tissue was washed, and incubated in digestion
media (collagenase VIII-300 U/ml, Sigma, St. Louis, Mo.; Dnase
1-1.5 .mu.g/mL, Sigma) for 1 hour. Single cell suspensions were
obtained by pouring the digestion mixture over a fine nylon sieve.
Cells were subsequently washed and Peyer's patch lymphocytes
separated on a 75%/40% Percoll gradient. Lamina propria lymphocytes
were isolated by opening residual intestinal tissue longitudinally,
washing extensively, cutting intestines into short segments, and
incubating in 1 mM EDTA to remove the epithelial layer. After EDTA
treatment, the tissue was washed in RPMI (Irvine Scientific,
Irvine, Calif.) supplemented with 10% heat-inactivated fetal calf
serum (Gibco BRL, Gaithersburg, Md.), 2 mM L-glutamine (Cellgro,
Natham, Va.), 100 U/mL penicillin and 100 .mu.g/mL streptomycin
(Pen/Strep, Cellgro), and fungizone (Gibco BRL). The tissue was
poured over a coarse sieve and residual tissue was incubated with
digestion media. The lamina propria lymphocyte digestion mixture
was poured over a fine nylon sieve to obtain a single cell
suspension and then lymphocytes were purified on a 75%/40% Percoll
gradient. These procedures resulted in >90% viability of all
lymphocyte preparations.
Immunologic assays: Antibody levels were determined by routine
ELISA techniques. Antibody levels are expressed in units/mL based
on pooled high titer anti-gp120 standards. The undiluted IgG and
IgG2a standards and the IgA standard were given arbitrary
concentrations of 200,000, and 80,192 U/ml, respectively. Samples
were compared to the standard curve on each plate using the
DeltaSOFT II v. 3.66 program (Biometallics, Princeton, N.J.).
For CTL assays, 7.times.10.sup.6 splenocytes, Peyer's patch
lymphocytes, or lamina propria lymphocytes were cultured in
supplemented RPMI with 6.times.10.sup.6 mitomycin C-treated naive
splenocytes in the presence of recombinant human IL-2 (50 IU/mL,
PharMingen, San Diego, Calif.) and a HIV-1 class I
(H2.sup.d)-restricted gp120 peptide, (p18-I10; R-G-P-G-R-A-F-V-T-I;
4 .mu.g/mL) (SEQ ID NO:8). After 5 days, restimulated cells were
harvested and specific lysis of target cells was measured using the
Cytotox 96 assay kit according to the manufacturer's instructions
(Promega, Madison, Wis.).
IFN.gamma., MIP1.alpha., and MIP1.beta. responses were evaluated by
incubation of splenocytes, Peyer's patch lymphocytes or lamina
propria lymphocytes at 5.times.10.sup.5 cells/ml in 96 well plates
in a final volume of 200 .mu.L of supplemented RPMI with gp120 (10
.mu.g/mL) or p18-I10 (4 .mu.g/mL). Culture supernatants were
harvested at 72 hours and analyzed by ELISA for IFN.gamma.
(PharMingen), MIP1.alpha., MIP1.beta., or RANTES content (R&D
Systems, Inc., Minneapolis, Minn.), according to the
manufacturers's recommendations. Each culture supernatant was
compared to the standard curve on the plate using the DeltaSOFT II
v. 3.66 program.
ELISPOT assays were performed using nitrocellulose-backed 96 well
plates (Millipore, Bedford, Mass.). Plates were coated with 50
.mu.l of PBS containing rat anti-mouse IFN.gamma. antibody
(PharMingen) at 10 .mu.g/mL or goat anti-mouse MIP1.alpha. antibody
(R&D) at 5 .mu.g/mL and incubated overnight at 4.degree. C.
Wells were washed with BBS/0.05% Tween-20 and then blocked with 200
.mu.L of supplemented RPMI for one hour at 37.degree. C. Serial
dilutions of splenocytes from each mouse starting at
2.times.10.sup.6 cells/well were then plated and incubated in
triplicate wells in media alone or with gp120 (10 .mu.g/mL) or
P18-I10 (4 .mu.g/mL). After 24 hours, wells were washed and
biotinylated anti-IFN.gamma. (PharMingen) or biotinylated
anti-MIP1.alpha. (R&D) was added to the appropriate wells for
two hours at room temperature. Wells were then washed and
horseradish peroxidase-streptavidin conjugate (Zymed, South San
Francisco, Calif.) was added for one hour at room temperature.
Plates were then developed by adding TMB Membrane Substrate
(Kierkegaard and Perry Laboratories, Gaithersburg, Md.) per the
manufacturer's instructions. Plates were dried and spots counted
using a dissecting microscope. The number of peptide-specific
cytokine-secreting cells was determined as a frequency of total CD8
T cells by using a correction factor based on the fraction of CD8 T
cells present in spleens of untreated and CD4-depleted mice as
determined by flow cytometry.
Statistical analyses: Statistical analyses were performed using the
GraphPad Prism program (GraphPad Software, Inc., San Diego,
Calif.). The significance of differences in means between multiple
groups was determined using one-way analysis of variance (ANOVA)
with Bonferroni's post-test analysis. When only two groups were
compared, the significance of differences in means between the two
groups was determined by unpaired t-test. Significant differences
were defined as p<0.05.
Results
Synthesis of the gp120:ISS Conjugate
Because the optimal antigenic targets for HIV vaccine development
have not yet been established, the present studies with gp120
represent a proof of principle for the application of ISS-based
immunization strategies to the generation of improved immunity to
other and better HIV target antigens as they are identified. We
generated the gp120:ISS conjugate to determine whether ISS
conjugation might generate an improved immune response to this
relatively poorly immunogenic HIV antigen. ODNs containing ISS (7.5
kD) were conjugated to gp120 protein (120 kD) as described in the
methods. Coomasie blue staining after SDS-PAGE of the gp120:ISS
conjugate revealed a 140 kD band, reflecting a protein:ODN ratio of
approximately 1:3. Western blot analysis with anti-gp120 antibody
and southwestern blot analysis with radioactively labeled ODNs
complementary to the ISS confirmed successful conjugation.
Conjugation of gp120 to a non-stimulatory, mutated ODN (mODN) for
use as a control was also performed and verified by the same
methods.
Intradermal immunization with ISS-based gp120 vaccines elicits a
Th1-biased immune response and chemokine secretion.
To determine if ISS could improve humoral and cytokine responses to
gp120, BALB/c mice were immunized intradermally (i.d.) with
co-administered gp120+ISS or with gp120:ISS conjugate. For
comparison, control mice were immunized with gp120 alone,
gp120+mODN, or gp120:mODN conjugate. In pilot experiments, ISS
co-administered with gp120 at a dose similar to that present in the
conjugate (1.3 .mu.g of ISS per mouse), led to immune responses
similar to those seen after immunization with gp120 alone.
Therefore, in subsequent studies where unconjugated ISS was
co-delivered with gp120, a 40-fold higher dose of ISS (50 .mu.g)
was used.
gp120 is a poor antigenic target for the generation of HIV
neutralizing antibodies. Therefore, humoral immune responses to the
vaccination reagents under study were determined by measuring
antigen-specific total IgG and IgG2a (Th1 dependent) levels from
serum collected twelve weeks after initiation of immunization (FIG.
12A). Compared with controls, mice i.d. immunized with gp120+ISS or
gp120:ISS conjugate showed significantly higher levels of total IgG
and IgG2a (p<0.001). In addition, both gp120+ISS
co-administration and gp120:ISS immunization improved IgGI
responses relative to control immunizations.
IFN.gamma. production is a hallmark feature of Th1 biased immunity
and contributes to protection against many viral infections.
Therefore, the CD4 T cell IFN.gamma. response of immunized mice was
determined by culture of splenocytes with gp120 and analysis of
supernatants by ELISA (FIG. 12B). IFN.gamma. production was
significantly higher for mice immunized with gp120+ISS (p<0.05)
or gp120:ISS conjugate (p<0.001) vs. control immunized mice.
Furthermore, gp120:ISS conjugate was more effective at inducing an
IFN.gamma. response than gp120+ISS (p<0.001).
The CCR5 chemokine receptor acts as a co-receptor for HIV entry
into cells and competitive inhibition of this virus/co-receptor
interaction by .beta.-chemokines (MIP1.alpha., MIP1.beta., and
RANTES) inhibits the intercellular spread of HIV and the natural
progression of the infection to AIDS. The ability of ISS to induce
CCR5 specific .beta.-chemokine production from macrophages in an
antigen-independent manner led us to investigate whether ISS-based
vaccines could elicit their antigen-specific production.
Antigen-specific secretion of MIP1.alpha., MIP1.beta., and RANTES
was assessed by ELISA of supernatants from splenocytes cultured
with gp120 (FIG. 12C and 12D). Mice immunized with gp120:ISS
conjugate demonstrated significantly stronger MIP1.alpha. and
MIP1.beta. responses than controls (p<0.001) or
gp120+ISS-immunized mice (p<0.001 for MIP1.alpha. and p<0.05
for MIP1.beta.). However, while less effective then gp 120:ISS
conjugate, gp120+ISS co-administration also elicited significant
MIP1.beta. but not MIP1.alpha. production. gp120-specific RANTES
production was not appreciably induced above background levels in
this series of experiments.
Intranasal immunization with ISS-based gp120 vaccines elicits
systemic and mucosal immune responses.
Protection against HIV infection is likely to require immunity at
mucosal sites, as 1) its spread is principally by sexual
transmission, 2) the intestinal mucosa represents an important site
for the initial replication of the virus, and 3) mucosal but not
systemic immunity provides protection against mucosal challenge in
models of viral infection. As mucosal immunity is best elicited by
vaccine delivery to mucosal sites, the immunization reagents
described in the previous sections were administered intranasally
(i.n.) to mice at the same doses used for i.d. immunization, and
both systemic and mucosal immune parameters were measured. Similar
to i.d. immunization, i.n. immunization with gp120+ISS or gp120:ISS
conjugate elicited significantly higher levels of serum IgG and
IgG2a than controls (p<0.001) (FIG. 13A). However, unlike i.d.
immunization, i.n. immunization with gp120+ISS induced a weaker IgG
(p<0.05) and IgG2a (p<0.001) response than the conjugate.
Furthermore, i.n. vaccination with gp120/ISS or gp120:ISS conjugate
also induced a vigorous secretory IgA response detected in vaginal
washes and fecal samples (p<0.001 vs. controls) (FIG. 13B). In
contrast, i.d. vaccination with these reagents failed to elicit a
significant mucosal IgA response. Finally, i.n. immunization with
either gp120+ISS or gp120:ISS conjugate elicited significantly more
gp120-specific IFN.gamma., MIP1.alpha., and MIP1.beta. production
than control vaccinations (p<0.001 for IFN.gamma., p<0.05 for
MIP1.alpha. and MIP1.beta.; FIGS. 13C-E).
ISS-based gp120 vaccines elicit systemic and mucosal CTL
activity.
Since an effective CD8 CTL response is important in preventing and
controlling HIV infection, the ability of ISS-based gp120
immunization to elicit antigen-specific CTL activity was next
determined. Both i.d. (FIG. 14A) and i.n. (FIG. 14B) administration
of gp120:ISS conjugate elicited similar levels of high specific
lysis in splenic CTL assays. However, while i.d. administration of
gp120+ISS elicited CTL activity that was similar to the conjugate,
i.n. administration of gp120+ISS elicited a significantly lower CTL
response (p<0.05). In addition to systemic CTL activity, i.n.
gp120:ISS conjugate delivery and to a much lesser extent gp120+ISS
co-administration induced mucosal CTL responses as measured with
lamina propria (FIG. 14C) and Peyer's patch lymphocytes (FIG. 14D).
However, consistent with the poor secretory IgA response seen after
systemic vaccination, both i.d. gp120+ISS and gp120:ISS conjugate
immunizations induced only weak CTL responses at these mucosal
sites.
ISS-based gp120 vaccines elicit MHC class I-restricted cytokine and
chemokine responses.
The cytokine and chemokine data described in the previous sections
reflect MHC class II-dependent responses, as intact gp120 protein
was used to stimulate cells. Cytokine and chemokine secretion by CD
8 T cells, in addition to CTL responses, are important for
controlling HIV infection, while CD4 T cell deficiency is a
characteristic feature of AIDS. Therefore, the ability of ISS-based
vaccines to induce cytokine and chemokine responses from CD8 T
cells was investigated. Splenocytes from immunized mice were
restimulated in vitro with MHC class I (H2.sup.d)-restricted gp120
peptide and cytokine and chemokine production in culture
supernatants was subsequently determined by ELISA (FIGS. 15A-C).
Mice immunized i.d. with either gp120+ISS or gp120:ISS conjugate
demonstrated significant CD8 T cell production of IFN.gamma.,
MIP1.alpha., and MIP1.beta. compared to control immunized mice.
Similar results were seen with i.n. gp120+ISS and gp120:conjugate
vaccination.
The class I restricted cytokine, chemokine, and CTL responses
elicited by gp120:ISS immunization are CD4 T cell-independent.
During the course of HIV infection, CD4 T cells are depleted.
Therefore, it would be important for a therapeutic AIDS vaccine to
elicit robust immunity in the absence of CD4 T cells. The ability
of ISS-based vaccines to elicit cytokine, chemokine, and CTL
responses from CD8 T cells led us to investigate whether these
responses required CD4 T cell help. Previous investigations have
demonstrated that ovalbumin:ISS (OVA:ISS) conjugate vaccination
induces equivalent CTL responses in CD4 knockout and wild type
mice, while the CTL response of OVA+ISS vaccinated CD4 knockout
mice is compromised. Therefore, gp120:ISS conjugate was used to
i.d. immunize mice depleted of CD4 T cells with anti-CD4 mAb and
non-CD4 T cell depleted mice, to compare their CD8 T cell
responses. Splenocytes from gp120:ISS conjugate immunized CD4 T
cell-depleted mice that were restimulated with a class I restricted
gp120 peptide demonstrated a retained ability to secrete
antigen-specific IFN.gamma. (FIG. 16A), MIP1.alpha. (FIG. 16B), and
MIP1.beta. (FIG. 16C) relative to splenocytes from immunized mice
that were not CD4 T cell depleted.
Furthermore, by ELISPOT analysis, gp120:ISS conjugate immunized CD4
T cell depleted and non-CD4 T cell depleted mice had equivalent
frequencies of CD8 T cells producing IFN.gamma. and MIP1.alpha. in
response to incubation with a class I restricted gp120 peptide
(FIG. 16D). Consistent with these results, antigen-specific CTL
activity was also retained in CD4 T cell depleted mice (FIG. 16E).
As expected, restimulation of splenocytes from immunized CD4 T cell
depleted mice with gp120 protein failed to elicit cytokine or
chemokine responses. Furthermore, CD4 T cell depleted mice were
unable to generate a detectable antibody response after gp120:ISS
conjugate immunization in spite of their development of CD8 T cell
immunity. Similar to i.d. immunized mice, CD4 T cell depleted mice
immunized i.n. with gp120:ISS conjugate also showed retained CD8 T
cell responses.
While the present invention has been described with reference to
the specific embodiments thereof, it should be understood by those
skilled in the art that various changes may be made and equivalents
may be substituted without departing from the true spirit and scope
of the invention. In addition, many modifications may be made to
adapt a particular situation, material, composition of matter,
process, process step or steps, to the objective, spirit and scope
of the present invention. All such modifications are intended to be
within the scope of the claims appended hereto.
SEQUENCE LISTING <100> GENERAL INFORMATION: <160>
NUMBER OF SEQ ID NOS: 8 <200> SEQUENCE CHARACTERISTICS:
<210> SEQ ID NO 1 <211> LENGTH: 22 <212> TYPE:
DNA <213> ORGANISM: Artificial Sequence <220> FEATURE:
<223> OTHER INFORMATION: Disulfide-linked phosphorothioate
ISS-ODN <400> SEQUENCE: 1 tgactgtgaa cgttcgagat ga 22
<200> SEQUENCE CHARACTERISTICS: <210> SEQ ID NO 2
<211> LENGTH: 22 <212> TYPE: DNA <213> ORGANISM:
Artificial Sequence <220> FEATURE: <223> OTHER
INFORMATION: mutated ODN <400> SEQUENCE: 2 tgactgtgaa
ccttcgagat ga 22 <200> SEQUENCE CHARACTERISTICS: <210>
SEQ ID NO 3 <211> LENGTH: 22 <212> TYPE: DNA
<213> ORGANISM: Artificial Sequence <220> FEATURE:
<223> OTHER INFORMATION: phosphorothioate ISS-ODN <400>
SEQUENCE: 3 tgactgtgaa cgttcgagat ga 22 <200> SEQUENCE
CHARACTERISTICS: <210> SEQ ID NO 4 <211> LENGTH: 8
<212> TYPE: PRT <213> ORGANISM: Artificial Sequence
<220> FEATURE: <223> OTHER INFORMATION: OVA peptide
<400> SEQUENCE: 4 Ser Ile Ile Asn Phe Glu Lys Leu 1 5
<200> SEQUENCE CHARACTERISTICS: <210> SEQ ID NO 5
<211> LENGTH: 9 <212> TYPE: PRT <213> ORGANISM:
Artificial Sequence <220> FEATURE: <223> OTHER
INFORMATION: Influenza virus nucleoprotein peptide <400>
SEQUENCE: 5 Ala Ser Asn Glu Asn Met Glu Thr Met 1 5 <200>
SEQUENCE CHARACTERISTICS: <210> SEQ ID NO 6 <211>
LENGTH: 22 <212> TYPE: DNA <213> ORGANISM: Artificial
Sequence <220> FEATURE: <223> OTHER INFORMATION:
mutated control ODN <400> SEQUENCE: 6 tgactgtgaa ccttcgagat
ga 22 <200> SEQUENCE CHARACTERISTICS: <210> SEQ ID NO 7
<211> LENGTH: 22 <212> TYPE: DNA <213> ORGANISM:
Artificial Sequence <220> FEATURE: <223> OTHER
INFORMATION: mODN <400> SEQUENCE: 7 tgactgtgaa ccttagagat ga
22 <200> SEQUENCE CHARACTERISTICS: <210> SEQ ID NO 8
<211> LENGTH: 10 <212> TYPE: PRT <213> ORGANISM:
Artificial Sequence <220> FEATURE: <223> OTHER
INFORMATION: HIV-1 class I-restricted gp120 peptide <400>
SEQUENCE: 8 Arg Gly Pro Gly Arg Ala Phe Val Thr Ile 1 5 10
* * * * *