U.S. patent application number 10/732783 was filed with the patent office on 2004-06-24 for treatment and prevention of immunodeficiency virus infection by administration of non-pyrogenic derivatives of lipid a.
Invention is credited to Crowley, Richard, Hone, David M., Lewis, George.
Application Number | 20040120924 10/732783 |
Document ID | / |
Family ID | 25470910 |
Filed Date | 2004-06-24 |
United States Patent
Application |
20040120924 |
Kind Code |
A1 |
Hone, David M. ; et
al. |
June 24, 2004 |
Treatment and prevention of immunodeficiency virus infection by
administration of non-pyrogenic derivatives of lipid A
Abstract
The present inventors have found that certain preparations
containing LPS and/or lipid A variants, derivatives, and/or analogs
demonstrate non-pyrogenic properties and exhibit anti-viral
activities. In particular, non-pyrogenic preparations of LPS, lipid
A, LPS antagonists and lipid A antagonists, and derivatives thereof
induce .beta. chemokine secretion, such as MIP-1.beta., but not
proinflammatory cytokines, such as TNF.alpha., IL-1.beta. and IL-6.
Non-pyrogenic preparations of the invention have been demonstrated
by the Applicant to suppress HIV replication in human peripheral
blood monocytes, as described by way of example herein. The present
invention provides preparations of LPS or lipid A variants, analogs
and derivatives of decreased or absent pyrogenicity which can be
used as therapeutics for the treatment or prevention of
immunodeficiency virus infection and its consequences.
Inventors: |
Hone, David M.; (Ellicott
City, MD) ; Crowley, Richard; (Gaithersburg, MD)
; Lewis, George; (Baltimore, MD) |
Correspondence
Address: |
INTELLECTUAL PROPERTY / TECHNOLOGY LAW
PO BOX 14329
RESEARCH TRIANGLE PARK
NC
27709
US
|
Family ID: |
25470910 |
Appl. No.: |
10/732783 |
Filed: |
December 10, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10732783 |
Dec 10, 2003 |
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09383709 |
Aug 26, 1999 |
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09383709 |
Aug 26, 1999 |
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08938106 |
Sep 26, 1997 |
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6368604 |
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Current U.S.
Class: |
424/85.1 ;
514/220; 514/46; 514/50; 514/54 |
Current CPC
Class: |
A61P 31/18 20180101;
A61K 39/02 20130101; Y02A 50/30 20180101; A61K 45/06 20130101; A61K
31/7024 20130101; Y02A 50/478 20180101 |
Class at
Publication: |
424/085.1 ;
514/054; 514/046; 514/050; 514/220 |
International
Class: |
A61K 031/739; A61K
031/7076; A61K 031/7072; A61K 038/19 |
Claims
What is claimed is:
1 A method of treating or preventing immunodeficiency virus
infection or a consequence thereof in a human subject in need of
such treatment or prevention comprising administering to the
subject an amount effective to treat or prevent immunodeficiency
virus infection or a consequence thereof of a composition
comprising a variant, derivative, or analog of lipopolysaccharide
or lipid A, which variant or derivative or analog (a) exhibits
substantially no pyrogenicity or reduced pyrogenicity relative to
lipopolysaccharide or lipid A, and (b) is active in inducing the
secretion of one or more .beta. chemokines but exhibits decreased
induction relative to lipopolysaccharide and lipid A of one or more
proinflammatory cytokines.
2. The method of claim 1 wherein the immunodeficiency virus is
human immunodeficiency virus.
3. The method of claim 2 which further comprises administering to
the subject a therapeutically effective amount of a chemokine.
4. The method of claim 3 which further comprises administering to
the subject a therapeutically effective amount of a chemokine
selected from the group consisting of RANTES, MIP-1.alpha. and
MIP-1.beta..
5. The method of claim 2 which further comprises administering to
the subject an anti-viral drug other than a lipopolysaccharide or
lipid A variant or analog or derivative of reduced or absent
pyrogenicity.
6. The method of claim 5 in which the anti-viral drug is selected
from one or more of the group consisting of AZT, 3TC, ddI, ddC,
3TC, and sequinavir.
7. The method of claim 5 in which the anti-viral drug is selected
from a protease inhibitor or a glycosylation inhibitor.
8. The method of claim 1 in which said lipopolysaccharide variant
is administered, which variant is isolated from a gram negative
bacterium.
9. The method of claim 8 in which the lipopolysaccharide variant is
isolated from a gram negative microorganism containing at least one
mutation in a gene selected from the group consisting of kdsA,
kdsB, htrB, msbB, lxp A, lxp B and kdt A.
10. The method of claim 8 in which the lipopolysaccharide variant
is obtained by a method comprising isolating a preparation
containing lipopolysaccharide from a gram negative microorganism
containing at least one mutation in one of the genes encoding
myristoyl transferase or one of the genes encoding lauroyl
transferase.
11. The method of claim 8 in which the lipopolysaccharide variant
is obtained by a method comprising isolating a preparation
containing lipopolysaccharide from a gram negative bacteria
selected from the group consisting of: Haemophilus influenzae,
Escherichia coli, Salmonella enterica, Klebsiella pneumoniae,
Bordella pertussis, Pseudomonas aeruginosa, Chlamydia psittaci, and
Legionella pneumophila.
12. The method of claim 8 in which the lipopolysaccharide variant
is isolated from an E. coli strain htrB1::Tn10 msbB::.omega.cam
double mutant.
13. The method of claim 8 in which the lipopolysaccharide variant
is isolated from Rhodobacter sphaeroides or Rhizobium
leguminosarum.
14. The method of claim 1 in which said derivative of a
lipopolysaccharide is administered, which derivative is obtained by
a method comprising modifying naturally occurring
lipopolysaccharide.
15. The method of claim 2 in which said derivative of a
lipopolysaccharide is administered, which is a derivative obtained
by a method comprising modifying naturally occurring
lipopolysaccharide.
16. The method of claim 14 in which the derivative is obtained by
treating a naturally occurring lipopolysaccharide with acyloxyacyl
hydrolase.
17. The method of claim 14 in which the derivative is obtained by
subjecting a naturally occurring lipopolysaccharide to alkaline
hydrolysis.
18. The method of claim 14 in which the derivative is obtained by
subjecting a naturally occurring lipopolysaccharide to
deacylation.
19. The method of claim 14 in which the derivative has a shortened
carbon backbone relative to the lipopolysaccharide.
20. The method of claim 14 in which the derivative is modified in
that one or more of the glucosamine residues are substituted with
galactosamine residues.
21. The method of claim 14 in which the derivative is a
nonphosphoryl or monophosphoryl form of the lipopolysaccharide.
22. The method of claim 14 in which the derivative is in a purified
form.
23. The method of claim 1 in which an analog is administered, which
analog is a synthetic analog of lipopolysaccharide or lipid A.
24. The method of claim 23 wherein the synthetic analog is lipid
X.
25. The method of claim 23 wherein the synthetic analog is lipid
IV.sub.A.
26. The method of claim 23 wherein the synthetic analog contains a
2-deoxy-2-aminogluconate residue in place of the
glucosamine-1-phosphate at the reducing end and bears a
galacturonic acid moiety instead of a phosphate at position 4'.
27. The method of claim 23 wherein the synthetic analog contains
the pentaacyl structure of the lipopolysaccharide found in
Rhodobacter sphaeroides.
28. The method of claim 23 wherein the synthetic analog lacks
phosphate and the glucosamine disaccharide is replaced by a
different chemical structure.
29. The method of claim 2 wherein the composition comprises a first
and second molecule selected from among said variant, derivative
and analog, in which the first and second molecules differ.
30. The method of claim 1 wherein said composition further
comprises a lipopolysaccharide or lipid A containing structure
isolated from a gram-negative microorganism.
31. The method of claim 30 wherein said variant, derivative, or
analog is a lipopolysaccharide antagonist, and said
lipopolysaccharide antagonist is in molar excess of the
lipopolysaccharide or lipid A containing structure.
32. A method of screening a preparation comprising a variant,
derivative or analog of lipopolysaccharide or lipid A, of reduced
or absent pyrogenicity, for anti-immunodeficiency virus activity
comprising assaying said preparation for the ability to inhibit
immunodeficiency virus replication or expression of
immunodeficiency virus RNA or protein or to alleviate symptoms of
an immunodeficiency virus-induced disorder.
33. The method of claim 32 in which the immunodeficiency virus is
HIV.
34. The method of claim 33 in which the preparation is assayed by a
method comprising measuring HIV-1 p24 antigen levels in cultured
hematopoietic cells acutely infected with HIV-1, which cells have
been contacted with the preparation; and comparing the measured
HIV-1 p24 antigen levels in the cells which have been contacted
with the lipopolysaccharide preparation with said levels in cells
not so contacted with the preparation, wherein a lower level in
said contacted cells indicates that the preparation has anti-HIV
activity.
35. The method of claim 33 in which the preparation is assayed by a
method comprising measuring the activity of a reporter gene product
expressed from a construct in which the HIV-1 LTR is operably
linked to said reporter gene, wherein said construct is present in
cultured cells which have been contacted with the preparation; and
comparing the measured expression of said reporter gene in the
cells which have been contacted with the preparation with said
levels in such cells not so contacted, wherein a lower level in
said contacted cells indicates that the preparation has anti-HIV
activity.
36. The method of claim 33 in which the preparation is assayed by a
method comprising measuring HIV-1 derived RNA transcripts or HIV-1
antigen levels in HIV-1 transgenic mice administered the
preparation; and comparing the measured transcript or antigen
levels in the mice which have been administered the preparation
with said levels in mice not so administered, wherein a lower level
in said administered mice indicates that the preparation has
anti-HIV activity.
37. The method of claim 33 in which the preparation is assayed by a
method comprising measuring SIV p27 antigen levels in the
peripheral blood mononuclear cells of SIV infected monkeys
administered the preparation; and comparing the measured antigen
levels in the monkeys which have been administered the preparation
with said levels in monkeys not so administered, wherein a lower
level in said administered monkeys indicates that the preparation
has anti-HIV activity.
38. A pharmaceutical composition comprising an amount effective to
treat or prevent immunodeficiency virus infection of a preparation
comprising a variant, derivative, or analog of lipopolysaccharide
or lipid A, that exhibits reduced or absent pyrogenicity; and a
pharmaceutically acceptable carrier.
39. The pharmaceutical composition of claim 38 which is formulated
as a controlled release formula.
40. The pharmaceutical composition of claim 38 which further
comprises a therapeutically effective amount of a chemokine.
41. The pharmaceutical composition of claim 40 in which the
chemokine is one or more of the chemokines selected from the group
consisting of RANTES, MIP-1.alpha. and MIP-1.beta..
42. The pharmaceutical composition of claim 38 in which the
variant, derivative, or analog stimulates .beta. chemokine
secretion but does not stimulate pyrogenic cytokine release.
43. The pharmaceutical composition of claim 42 which is formulated
as a controlled release formula.
44. The pharmaceutical composition of claim 42 which further
comprises a therapeutically effective amount of a chemokine.
45. The pharmaceutical composition of claim 37 which comprises a
lipopolysaccharide variant isolated from a gram negative
microorganism.
46. The pharmaceutical composition of claim 45 which is formulated
as a controlled release formula.
47. The pharmaceutical composition of claim 45 which further
comprises a therapeutically effective amount of a chemokine.
48. The pharmaceutical composition of claim 47 in which the
chemokine is one or more of the chemokines selected from the group
consisting of RANTES, MIP-1.alpha. and MIP-1.beta..
49. The pharmaceutical composition of claim 45 in which the
lipopolysaccharide variant is isolated from a gram negative
microorganism containing at least one mutation in a gene selected
from the group consisting of kdsA, kdsB, htrB, msbB, lxp A, lxp B
and kdt A.
50. The pharmaceutical composition of claim 49 which is formulated
as a controlled release formula.
51. The pharmaceutical composition of claim 49 which further
comprises a therapeutically effective amount of a chemokine.
52. The pharmaceutical composition of claim 45 in which the
lipopolysaccharide variant is isolated from an E. coli strain
htrB1::Tn10 msbB::.omega.cam double mutant.
53. The pharmaceutical composition of claim 52 which is formulated
as a controlled release formula.
54. The pharmaceutical composition of claim 52 which further
comprises a therapeutically effective amount of a chemokine.
55. The pharmaceutical composition of claim 37 which comprises said
lipopolysaccharide derivative, in which the lipopolysaccharide
derivative is derived from a modified naturally occurring
lipopolysaccharide.
56. The pharmaceutical composition of claim 55 which is formulated
as a controlled release formula.
57. The pharmaceutical composition of claim 55 which further
comprises a therapeutically effective amount of a chemokine.
58. A pharmaceutical composition comprising an amount of lipid X or
lipid IV.sub.A effective to treat or prevent immunodeficiency virus
infection; and a pharmaceutical carrier.
59. The pharmaceutical composition of claim 58 which is formulated
as a controlled release formula.
60. The pharmaceutical composition of claim 58 which further
comprises a therapeutically effective amount of a chemokine.
61. The method of claim 2 in which the variant, derivative, or
analog is in purified form.
62. The method of claim 9 in which the variant, derivative, or
analog is in purified form.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of co-pending application
Ser. No. 09/383,709 filed on Aug. 26, 1999, which claims priority
to U.S. patent application Ser. No. 08/938,106 filed Sep. 26, 1997,
now U.S. Pat. No. 6,368,604.
1. FIELD OF THE INVENTION
[0002] The present invention relates to lipopolysaccharide (LPS) or
lipid A variants, derivatives, and analogs with non-pyrogenic and
non-endotoxic properties as well as methods for treatment and
prevention of immunodeficiency virus infection, in particular HIV
infection, using these LPS or lipid A variants and analogs and
derivatives. The present invention also relates to LPS and lipid A
antagonists and their use as therapeutics in the treatment and
prevention of HIV infection. The LPS and lipid A variants,
derivatives, and analogs of the present invention preferably induce
the secretion of .beta. chemokines but exhibit decreased induction
relative to LPS and lipid A of secretion of proinflammatory
cytokines, such as IL-1.beta., IL-6 and TNF-.alpha.. The present
invention further relates to pharmaceutical compositions for the
treatment and prevention of HIV infection.
2. BACKGROUND OF THE INVENTION
2.1. The Human Immunodeficiency Virus
[0003] The human immunodeficiency virus (HIV) has been implicated
as the primary cause of the slowly degenerative immune system
disease termed acquired immune deficiency syndrome (AIDS)
(Barre-Sinoussi, F., et al., 1983, Science 224:868-870; Gallo, R.,
et al., 1984, Science 224:500-503). There are at least two distinct
types of HIV: HIV-1 (Barre-Sinoussi, F., et al., 1983, Science
220:868-870; Gallo, R., et al., 1984, Science 224:500-503) and
HIV-2 (Clavel, F., et al., 1986, Science 233:343-346; Guyader, M.,
et al., 1987, Nature 326:662-669). Further, a large amount of
genetic heterogeneity exists within populations of each of these
types. In humans, HIV replication occurs prominently in CD4.sup.+ T
lymphocyte populations, and HIV infection leads to depletion of
this cell type and eventually to immune incompetence, opportunistic
infections, neurological dysfunctions, neoplastic growth, and
ultimately death.
[0004] HIV is a member of the lentivirus family of retroviruses
(Teich, N., et al., 1984, RNA Tumor Viruses, Weiss, R., et al.,
eds., CSH-Press, pp. 949-956). Retroviruses are small enveloped
viruses that contain a single-stranded RNA genome, and replicate
via a DNA intermediate produced by a virally-encoded reverse
transcriptase, an RNA-dependent DNA polymerase (Varmus, H., 1988,
Science 240:1427-1439).
[0005] The HIV viral particle comprises a viral core, composed in
part of capsid proteins, together with the viral RNA genome and
those enzymes required for early replicative events. Myristylated
gag protein forms an outer shell around the viral core, which is,
in turn, surrounded by a lipid membrane envelope derived from the
infected cell membrane. The HIV envelope surface glycoproteins are
synthesized as a single 160 kilodalton precursor protein which is
cleaved by a cellular protease during viral budding into two
glycoproteins, gp41 and gp120. gp41 is a transmembrane glycoprotein
and gp120 is an extracellular glycoprotein which remains
non-covalently associated with gp41, possibly in a trimeric or
multimeric form (Hammarskjold, M., & Rekosh, D., 1989, Biochem.
Biophys. Acta 989:269-280).
[0006] HIV is targeted to CD4.sup.+ cells because a CD4 cell
surface protein (CD4) acts as the cellular receptor for the HIV-1
virus (Dalgleish, A., et al., 1984, Nature 112:763-767; Klatzmann
et al., 1984, Nature 312:767-768; Maddon et al., 1986, Cell
47:333-348). Viral entry into cells is dependent upon gp120 binding
the cellular CD4 receptor molecules (McDougal, J. S., et al., 1986,
Science 231:382-385; Maddon, P. J., et al., 1986, Cell 47:333-348),
explaining HIV's tropism for CD4.sup.+ cells, while gp41 anchors
the envelope glycoprotein complex in the viral membrane. While
these virus:cell interactions are necessary for infection, there is
evidence that additional virus:cell interactions are also
required.
2.2. HIV Treatment
[0007] HIV infection is pandemic and HIV-associated diseases
represent a major world health problem. Although considerable
effort is being put into the design of effective therapeutics,
currently no curative anti-retroviral drugs against AIDS exist. In
attempts to develop such drugs, several stages of the HIV life
cycle have been considered as targets for therapeutic intervention
(Mitsuya, H., et al., 1991, FASEB J. 5:2369-2381). Many viral
targets for intervention with HIV life cycle have been suggested,
as the prevailing view is that interference with a host cell
protein would have deleterious side effects. For example, virally
encoded reverse transcriptase has been one focus of drug
development. A number of reverse-transcriptase-targeted drugs,
including 2',3'-dideoxynucleoside analogs such as AZT, ddI, ddC,
and d4T have been developed which have been shown to been active
against HIV (Mitsuya, H., et al., 1991, Science 249:1533-1544).
[0008] The new treatment regimens for HIV-1 show that a combination
of anti-HIV compounds, which target reverse transcriptase (RT),
such as azidothymidine (AZT), lamivudine (3TC), dideoxyinosine
(ddI), dideoxycytidine (ddC) used in combination with an HIV-1
protease inhibitor have a far greater effect (2 to 3 logs
reduction) on viral load compared to AZT alone (about 1 log
reduction). For example, impressive results have recently been
obtained with a combination of AZT, ddI, 3TC and ritonavir
(Perelson, A. S., et al., 1996, Science 15:1582-1586). However, it
is likely that long-term use of combinations of these chemicals
will lead to toxicity, especially to the bone marrow. Long-term
cytotoxic therapy may also lead to suppression of CD8.sup.+ T
cells, which are essential to the control of HIV, via killer cell
activity (Blazevic, V., et al., 1995, AIDS Res. Hum. Retroviruses
11: 1335-1342) and by the release of suppressive factors, notably
the chemokines Rantes, MIP-1.alpha. and MIP-1.beta. (Cocchi, F., et
al., 1995, Science 210:1811-1815). Another major concern in
long-term chemical anti-retroviral therapy is the development of
HIV mutations with partial or complete resistance (Lange, J. M.,
1995, AIDS Res. Hum. Retroviruses 10:S77-82). It is thought that
such mutations may be an inevitable consequence of anti-viral
therapy. The pattern of disappearance of wild-type virus and
appearance of mutant virus due to treatment, combined with
coincidental decline in CD4.sup.+ T cell numbers strongly suggests
that, at least with some compounds, the appearance of viral mutants
is a major underlying factor in the failure of AIDS therapy.
[0009] Attempts are also being made to develop drugs which can
inhibit viral entry into the cell, the earliest stage of HIV
infection. Here, the focus has thus far been on CD4, the cell
surface receptor for HIV. Recombinant soluble CD4, for example, has
been shown to inhibit infection of CD4.sup.+ T cells by some HIV-1
strains (Smith, D. H., et al., 1987, Science 238:1704-1707).
Certain primary HIV-1 isolates, however, are relatively less
sensitive to inhibition by recombinant CD4 (Daar, E., et al., 1990,
Proc. Natl. Acad. Sci. USA 87:6574-6579). In addition, recombinant
soluble CD4 clinical trials have produced inconclusive results
(Schooley, R., et al., 1990, Ann. Int. Med. 112:247-253; Kahn, J.
O., et al., 1990, Ann. Int. Med. 112:254-261; Yarchoan, R., et al.,
1989, Proc. Vth Int. Conf. on AIDS, p. 564, MCP 137).
[0010] The late stages of HIV replication, which involve crucial
virus-specific processing of certain viral encoded proteins, have
also been suggested as possible anti-HIV drug targets. Late stage
processing is dependent on the activity of a viral protease, and
drugs are being developed which inhibit this protease (Erickson,
J., 1990, Science 249:527-533).
[0011] Recently, chemokines produced by CD8.sup.+ T cells have been
implicated in suppression of HIV infection (Paul, W. E., 1994, Cell
82:177; Bolognesi, D. P., 1993, Semin. Immunol. 5:203). The
chemokines RANTES, MIP-1.alpha. and MIP-1.beta., which are secreted
by CD8.sup.+ T cells, were shown to suppress HIV-1 p24 antigen
production in cells infected with HIV-1 or HIV-2 isolates in vitro
(Cocchi, F, et al., 1995, Science 270:1811-1815). These chemokines,
alone or in combination, effectively suppressed the replication of
several primary isolates of HIV-1, HIV-2 and SIV when tested in a
variety of in vitro assays (Cocchi et al. supra). The mechanism of
chemokine-mediated suppression was further delineated by a series
of independent reports showing that .beta. chemokine suppression
CCR5 serves as a co-receptor for macrophage-tropic NSI isolates of
HIV (Alkhatib et al., 1996, Science 272:1955; Dragic et al., 1996,
Nature 381:667; Choe et al., 1996, Cell 85:1135; Berson et al.,
1996, J. Virology 70:6288). However, this activity is highly
specific since .beta. chemokines blocked macrophage tropic NSI
isolates but had no significant effect on T cell-tropic SI isolates
of HIV-1 (Cocchi et al., supra; Alkhatib et al., supra). Thus,
these and other chemokines may prove useful in therapies for some
strains of HIV infection. The clinical outcome, however, of all
these and other candidate drugs is still in question.
[0012] Attention is also being given to the development of vaccines
for the treatment of HIV infection. The HIV-1 envelope proteins
(gp160, gp120, gp41) have been shown to be the major antigens for
anti-HIV antibodies present in AIDS patients (Barin et al., 1985,
Science 228:1094-1096). Thus far, therefore, these proteins seem to
be the most promising candidates to act as antigens for anti-HIV
vaccine development. Several groups have begun to use various
portions of gp160, gp120, and/or gp41 as immunogenic targets for
the host immune system. See for example, Ivanoff, L., et al., U.S.
Pat. No. 5,141,867; Saith, G., et al., PCT International
Publication No. WO92/22,654; Shafferman, A., PCT International
Publication No. WO91/09,872; Formoso, C., et al., PCT International
Publication No. WO90/07,119. To this end, vaccines directed against
HIV proteins are problematic in that the virus mutates rapidly
rendering many of these vaccines ineffective. Clinical results
concerning these candidate vaccines, however, still remain far in
the future.
[0013] Thus, although a great deal of effort is being directed to
the design and testing of anti-retroviral drugs, effective,
non-toxic treatments are still needed.
2.3 Lipopolysaccharides
[0014] Endotoxins of gram-negative microorganisms fulfill a vital
function for bacterial viability, and induce in mammalians potent
pathophysiological effects. Chemically, they are
lipopolysaccharides consisting of an O-specific chain, a core
oligosaccharide, and a lipid component, termed lipid A. The latter
determines the endotoxic activities and together with the core
constituent 3-deoxy-D-manno-octulosonic acid (KDO), essential
functions for bacteria.
[0015] Under normal conditions, lipopolysaccharide (LPS) is
inserted in the outer surface of the outer membrane of gram
negative bacteria (Schnaitman and Klena, Microbiol Rev, 57:655-682
(1993)); and Makela and Stocker, In: Handbook of endotoxin volume
1, Elsevier Biomedical Press, Amsterdam, Rietschel (ed), pp. 59-137
(1984). Complete or "smooth" LPS is composed of three main domains
called lipid A, the O-antigen (also called the O-polysaccharide)
and the core region, which creates an oligosaccharide link between
lipid A and the O antigen (Schnaitman and Klena, supra; and Makela
and Stocker, supra). The O-antigen is composed of oligosaccharide
repeat units. The structure and number of these repeats varies
depending on the bacterial species and growth conditions, typically
ranging from one to fifty repeats (Schnaitman and Klena, supra; and
Makela and Stocker, supra). Some bacterial generi, such as
Neisseria spp., produce LPS that has low numbers of O-antigen
repeats and therefore is referred to as lipoligosaccharide (LOS)
simply to reflect this fact (Schnaitman and Klena, supra; and
Makela and Stocker, supra).
[0016] The biological properties of LPS have been extensively
investigated (Rietschel et al., FASEB J, 8:217-225 (1994); and
Raetz, J. Bacteriol, 175:5745-5753 (1993)). This molecule has
powerful pyrogenic properties and in humans purified LPS (at doses
of 200 ng to 1 .mu.g) has been shown to induce febrile responses
(Greisman and Homick, J. Immunol, 109:1210-1215 (1972); Greisman
and Homick, J. Infect Dis, 128:257-263 (1973); Abemathy and Spink,
J. Clin Invest, 37:219-225 (1958); Rietschel et al., supra; and
Raetz, supra (1993)). These febrile responses are mediated by host
proinflammatory cytokines IL-1, IL-6, and TNF-.alpha., the
secretion of which is induced by LPS (Rietschel et al., supra and
Raetz, supra).
[0017] The biologically active component of LPS is lipid A
(Rietschel et al., supra; Verma et al., Infect Immun.,
60(6):2438-2444 (1992); Alving, J Immunol Meth., 140:1-13 (1991);
Alving and Richards, Immunol Lett., 25:275-280 (1990); and Richard
et al., Infect Imunn., 56:682-686 (1988)). Activity analysis of
lipid A biosynthesis precursors or synthetic intermediates showed
that various elements of lipid A are essential for pyrogenicity
(Rietschel et al., supra; Raetz, supra).
[0018] For several years, it has been known that under certain
circumstances, stimulation with bacterial LPS protects macrophages
from HIV infection (Kornbluth et al., 1989, J. Exp. Medicine
169:1137; Bernstein et al., 1991, J. Clinical Invest. 88:540;
Bagasra et al., 1992, Proc. Natl. Acad. Sci, 89:6285). LPS-mediated
suppression is thought to be dependent on LPS-CD14 interactions
(Bagasra et al., supra), the induction of .beta. chemokines
MIP-1.alpha., MIP-1.beta. and RANTES (Verani et al., 1997, J. Exp.
Med. 185:805) and down regulation of .beta. chemokine receptors
(Sica et al., 1997, J. Exp. Med. 185:969).
[0019] In attempts to detoxify the effects of LPS or lipid A in the
treatment of Gram-negative bacteremia and septic shock, antibodies
have been designed which detoxify the endotoxin activity by
hydrolyzing the LPS or lipid A to products with reduced toxicity
(see U.S. Pat. No. 5,597,573, issued Jan. 28, 1997).
[0020] LPS and lipid A are potent activators of pro-inflammatory
cytokines, which accounts for the pyrogenic nature of these
molecules. LPS has been shown to suppress HIV replication.
LPS-induced suppression of HIV may be mediated through induction
and/or down regulation of chemokine receptors. However, due to the
toxicity of this molecule, LPS and lipid A are not viable
candidates for the treatment of HIV.
[0021] Citation of references hereinabove shall not be construed as
an admission that such references are prior art to the present
invention.
3. SUMMARY OF THE INVENTION
[0022] The present inventors have found that certain preparations
containing LPS and/or lipid A variants, derivatives, and/or analogs
demonstrate non-pyrogenic properties and exhibit anti-viral
activities, particularly anti-HIV activities. In particular,
non-pyrogenic preparations of LPS, lipid A, LPS antagonists and
lipid A antagonists, and derivatives thereof induce .beta.
chemokine secretion, such as MIP-1.alpha. and MIP-1.beta., but not
proinflammatory cytokines, such as TNF.alpha., IL-1.beta. and IL-6.
The non-pyrogenic preparations of the invention, have been
demonstrated by the Applicant to suppress HIV replication in human
peripheral blood monocytes, as described by way of example herein.
The present invention provides preparations of reduced or
substantially negligible pyrogenicity of LPS variants and lipid A
variants, and analogs and derivatives thereof which may be used as
therapeutics for the treatment of human immunodeficiency virus
infection.
[0023] The present invention also encompasses synthetic lipid A and
LPS antagonists, such as, but not limited to, lipid X and lipid
IV.sub.A, which suppress immunodeficiency virus replication, in
particular, HIV-1 replication, and exhibit decreased induction
relative to LPS and lipid A of proinflammatory cytokines such as
IL-6, TNF.alpha. and IL-1.beta.. The lipopolysaccharide
compositions of the present invention include those antagonists,
derivatives or analogs of LPS and lipid A which exhibit reduced
pyrogenicity and proinflammatory activity relative to wild-type LPS
and lipid A, respectively, yet stimulate .beta. chemokine secretion
and inhibit HIV replication. The present invention fills a
tremendous need for a non-toxic, long-term treatment of HIV
infection and its sequelae, ARC and AIDS.
[0024] In particular, the present invention relates to LPS or lipid
A preparations isolated from gram negative organisms containing at
least one mutation from the group kdsA, kdsB, htrB, msbB. In a
preferred embodiment of the present invention, non-pyrogenic LPS is
isolated from the E. coli htrB1::Tn10, msbB::.OMEGA.cam double
mutant MLK986.
[0025] The present invention further relates to preparations of LPS
or lipid A which have been differentially modified to yield reduced
pyrogenicity or, preferably, substantially non-pyrogenic properties
of the preparation relative to wild-type LPS and lipid A,
respectively. In specific embodiments, preparations are treated by
alkaline hydrolysis or acyloxyacyl hydrolase. Modified derivatives
also in accordance with the present invention are derived from the
group of monophosphoryl lipid A, penta-acyl lipid A, lipid IV.sub.A
or lipid X. The present invention still further relates to LPS or
lipid A derived from deacylation, by treatment with an alkali.
[0026] The present invention further relates to therapeutic methods
and compositions for treatment and prevention of diseases and
disorders associated with HIV-1 infection based on LPS or lipid A
derivatives and therapeutically and prophylactically effective
preparations containing a derivative of LPS or lipid A, and related
analogs. Non-pyrogenic derivatives of lipid A and LPS can be
identified by their failure to elicit a toxic response in mammals,
their lack of proinflammatory activity, and/or their lack of
induction of secretion of significant levels of pyrogenic
cytokines, including IL-1.beta., IL-6 and TNF.alpha.. Preferably,
non-pyrogenic derivatives are used in the therapeutic methods and
compositions of the invention; alternatively, derivatives of
reduced pyrogenicity relative to wild-type LPS and lipid A may be
employed.
[0027] The invention provides for the treatment and prevention of
HIV infection by administration of a therapeutic compound of the
invention. The therapeutic compounds of the present invention
include: lipid A or LPS derived from gram negative organisms
containing at least one mutation selected from the group kdsA,
kdsB, htrB, msbB, and derivatives and analogs of the foregoing;
preparations of lipid A or LPS which have been modified to have
reduced pyrogenic properties, including but not limited to, the
group of monophosphoryl lipid A, penta-acyl lipid A or lipid A or
LPS derivatives derived by deacylation of lipid A or LPS, treatment
of LPS and lipid A with acyloxyaclhydroxylase or by treatment with
an alkali, and derivatives and analogs of the foregoing. The
invention also provides in vitro and in vivo assays for assessing
the efficacy of therapeutics of the invention for treatment or
prevention of HIV. The invention also provides pharmaceutical
compositions and methods of administration of therapeutics of the
invention for treatment or prevention of HIV infection.
3.1. Definitions
[0028] As used herein, the following terms shall have the meanings
indicated.
1 AIDS Acquired Immune Deficiency Syndrome ARC AIDS-Related Complex
KS Kaposi's Sarcoma OI Opportunistic Infection PBMC Peripheral
Blood Mononuclear Cell
4. DESCRIPTION OF THE FIGURES
[0029] FIG. 1. Proinflammatory Activity of W3110 LPS and Mutant
Derivative MLK986 LPS. LPS was extracted from E. coli strain W3110
and a htrB1::Tn10, msbB::.OMEGA.cam double mutant (MLK986) after
being cultured at 30.degree. C., 37.degree. C. or 42.degree. C. To
characterize the proinflammatory activity of LPS harvested from
W3110 and MLK986, the level of TNF.alpha. in culture supernatants
was measured 8 hrs after stimulation of human PBMCs. Significant
levels of TNF.alpha. secretion was observed by the parent strain
W3110 LPS at concentrations above 1 mg/ml irrespective of culture
temperature. In contrast, LPS from mutant strain MLK986 cultured at
30.degree. C. only moderately elicited TNF.alpha. secretion and LPS
derived from MLK986 cultured at 37.degree. C. and 42.degree. C.
even at concentrations as high as 1 .mu.g/ml did not elicit
TNF.alpha. secretion in the human PBMC activation assay. Figure
Legend:
[0030] - - - - W/42
[0031] - - - - W/37
[0032] - - - - W/30
[0033] MLK/42
[0034] MLK/37
[0035] MLK/30
[0036] FIG. 2. LPS From MLK986 Stimulates P Chemokine
Secretion.
[0037] LPS isolated from MLK986, cultured at either 37.degree. C.
or 42.degree. C., and RsDPLA stimulated the secretion of
MIP-1.alpha. and MIP-1.beta. from human PBMCs in a dose-dependent
manner. Figure Legend:
[0038] MLK986/37
[0039] MLK986/42
[0040] RsDPLA
[0041] FIG. 3. The Peak Production of Chemokines Occurred 24 Hours
After MLK986 Stimulation.
[0042] The peak stimulation of chemokine production from human
PBMCs by LPS isolated from MLK986, cultured at either 37.degree. C.
or 42.degree. C., and RsDPLA occurred at 24 hours. The level of
RANTES was not significantly elevated after stimulation with MLK986
LPS or RsDPLA.
[0043] Figure Legend:
[0044] MLK986/37
[0045] MLK986/42
[0046] RsDPLA
[0047] Unstimulated
[0048] FIGS. 4A-C. Inhibition of HIV-1 Replication by Non-pyrogenic
Forms of LPS. FIG. 4A is representative of 4 different experiments
and demonstrates that MLK986/37 inhibits HIV-1 chemokines. FIG. 4B
MLK986/37 induced HIV-1 inhibition in MDM is reversed by addition
of a mixture of neutralizing antibodies against RANTES,
MIP-1.alpha., and MIP-1.beta. (from R&D Systems Inc.; 200 ug/ml
each). FIG. 4C HIV-1 replication inhibition occurred without
inducing pyrogenic cytokines. Figure Legend:
[0049] .box-solid. Control
[0050] .quadrature. LPS
[0051] LPS mutant
[0052] FIG. 5. Lipid A antagonist, lipid IV.sub.A, inhibits HIV
replication. PBMCs were treated with synthetic lipid IV.sub.A at
1000 ng/ml, 100 ng/ml and 10 ng/ml for 24 hours. The treated cells
were subsequently infected with 0.200 ng of HIV-1.sub.BAL (Cocchi
et al., supra) for 2 hours, washed twice and incubated for a
further 19 days. Culture supernatants were then collected and the
level of p24 in these supernatants was measured by ELISA (R&D
Systems). The results of this assay show that lipid IV.sub.A
suppresses the replication of HIV-1.sub.BAL in a dose-dependent
manner. Figure Legend:
[0053] .quadrature. Lipid IVa (1000 ng/ml)
[0054] Lipid IVa (100 ng/ml)
[0055] Lipid IVa (10 ng/ml)
[0056] .quadrature. MLK986/42 (1000 ng/ml)
[0057] MLK986/42 (100 ng/ml)
[0058] MLK986/42 (10 ng/ml)
5. DETAILED DESCRIPTION OF THE INVENTION
[0059] The present invention relates to forms of lipid A and LPS
which have reduced pyrogenicity as exhibited by reduced
proinflammatory and endotoxic activity, relative to wild-type lipid
A and LPS respectively, yet stimulate secretion of
.beta.-chemokines and are effective at inhibiting HIV replication
and/or infection in vitro or in vivo, decreasing viral load, and/or
treating or preventing disorders associated with HIV infection. The
present invention also relates to LPS and lipid A antagonists which
have reduced proinflammatory activity, yet stimulate secretion of
.beta.-chemokines and are effective at inhibiting HIV replication
and/or infection in vitro or in vivo, decreasing viral load, and/or
treating or preventing disorders associated with HIV infection. The
LPS and lipid A analogs (including antagonists) of the present
invention preferably induce the secretion of .beta.-chemokines but
exhibit decreased induction relative to wild-type LPS and lipid A
of the secretion of proinflammatory cytokines, such as, IL-.beta.,
IL-6 and TNF-.alpha., thereby providing a non-toxic treatment of
immunodeficiency virus infection, in particular, HIV infection and
its sequelae, ARC and AIDS. The LPS and lipid A variants,
derivatives, and analogs of the present invention exhibit decreased
pyrogenicity i.e., preferably induce the secretion of .beta.
chemokines but exhibit substantial induction relative to wild-type
LPS and lipid A of proinflammatory cytokines. Non-pyrogenic
derivatives of lipid A and LPS can be identified by their failure
to elicit a toxic or endotoxic response in mammals, their lack of
proinflammatory activity and/or their lack of induction of
secretion of significant levels of pyrogenic cytokines, e.g.,
IL-7B, IL-6, TNF.alpha.. Preferably, non-pyrogenic derivatives are
used in the therapeutic methods and compositions of the invention;
alternatively, derivatives of reduced pyrogenicity relative to
wild-type LPS or lipid A may be employed. LPS antagonists and lipid
A antagonists can be identified by their ability to interfere or
compete with the activities of LPS or lipid A, e.g., to
competitively inhibit the interaction between LPS and the cellular
receptor for LPS. Thus, by way of example, such an antagonist may
be identified by its ability to reduce the physiological
manifestation of LPS or lipid A activity, e.g., its ability to
reduce TNF.alpha. secretion from LPS-stimulated PBMCs.
[0060] Efficacy in treating or preventing HIV infection may be
demonstrated by detecting the ability to inhibit the replication of
the HIV virus, to inhibit HIV transmission, or to prevent HIV from
establishing itself in its host, or to prevent, ameliorate or
alleviate the symptoms of a disease caused by HIV infection, or
prevent disease progression. The treatment is considered
therapeutic if there is, for example, a reduction in viral load,
decrease in mortality and/or morbidity.
[0061] In specific embodiments, the invention provides an LPS
variant with substantially reduced pyrogenicity isolated from gram
negative organisms containing at least one mutation selected from
the group kdsA, kdsB, htrB or msbB. The present invention further
provides an isolated preparation of LPS which has been modified
relative to wild-type to yield its reduced or non-pyrogenic
properties, including but not limited to the group of
monophosphoryl lipid A, penta-acyl lipid A, lipid IV.sub.A or lipid
X. The present invention further provides for analogs or
derivatives of lipid A or lipopolysaccharide achieved by
deacylation, by the treatment with acyloxyacyl hydroxylase or by
the treatment with an alkali. The present invention further
provides synthetic LPS and lipid A molecules which substantially
lack or exhibit reduced proinflammatory activity and are effective
at inhibiting HIV replication.
[0062] The present invention further relates to therapeutic methods
and compositions for treatment and prevention of disorders
associated with immunodeficiency virus infection based on
non-pyrogenic or reduced-pyrogenic LPS and lipid A preparations and
therapeutically effective analogs and derivatives thereof. The
invention provides for treatment of HIV infection by administration
of a therapeutic compound of the invention. The therapeutic
compounds of the invention include preparations of reduced or
substantially absent pyrogenicity of LPS and lipid A which do
induce .beta. chemokines, such as MIP-1.alpha. and MIP-1.beta., and
related derivatives and analogs thereof. Lipopolysaccharides and
lipid A variants, analogs and derivatives which are effective for
treatment and prevention of HIV infection can be identified by in
vitro and in vivo assays such as those described in Section 5.3
infra.
[0063] In a preferred embodiment, a therapeutic composition of the
invention comprises an isolated lipopolysaccharide isolated from
gram negative organisms containing at least one mutation from the
group kdsA, kdsB, htrB or msbB, or a synthetic analog of
lipopolysaccharide which has been modified relative to wild-type to
yield reduced or absent pyrogenic properties, including but not
limited to the group of monophosphoryl lipid A, penta-acyl lipid A,
lipid IV.sub.A or lipid X. In other preferred embodiments, the
therapeutic comprises a lipopolysaccharide analogue or derivative
achieved by deacylation, by treatment with acyloxyacyl hydroxylase
or by treatment with an alkali. In yet another preferred
embodiment, the therapeutic comprises synthetic LPS and lipid A
molecules which lack or exhibit reduced proinflammatory activity
and are effective at inhibiting HIV replication.
[0064] For clarity of disclosure, and not by way of limitation, the
detailed description of the invention is divided into the
subsections which follow.
5.1. Lipopolysaccharide Variants and Derivatives and Analogs
Thereof with Reduced or Absent Pyrogenicity
[0065] The invention provides isolated preparations of
non-pyrogenic or reduced pyrogenic variants of LPS and lipid A and
isolated preparations of LPS or lipid A antagonists which exhibit
decreased induction relative to wild-type LPS and lipid A of
proinflammatory activity, yet preferably stimulate secretion of
.beta. chemokines and are effective for treatment or prevention of
immunodeficiency virus and/or HIV infection and resulting
disorders. Pyrogenicity of the preparations may be determined by
measuring the ability of the LPS or lipid A preparation to
stimulate the secretion of proinflammatory cytokines, e.g.,
IL-.beta., IL-6 and TNF.alpha., or by any method known in the art.
Effectiveness of the lipopolysaccharides of the invention for
treatment or prevention of HIV infection can be determined by any
of the methods disclosed in Section 5.3 infra or by any method
known in the art. In a specific embodiment, the LPS and lipid A
preparations and derivatives or analogs thereof inhibit HIV
infection.
[0066] In a preferred embodiment the lipid A antagonists or
lipopolysaccharides are derived from gram negative microorganisms
that have mutations in one of the following genes: kdsA, kdsB, htrB
or msbB.
[0067] In a preferred embodiment of the present invention, lipid X
or lipid IV.sub.A, both LPS and lipid A antagonists of reduced or
absent pyrogenicity, are used for the treatment of HIV. Lipid X is
a monosaccharide precursor of lipid A (Rietschel et al., supra; and
Raetz, supra (1993) and lipid IV.sub.A, a tetra-acyl precursor of
lipid A (Wang et al., Infect Immun., 59(12):4655-4664 (1991); Ulmer
et al., Infect Immun., 60(12):145-5152 (1992); Kovach et al., J.
Exp. Med., 172:77-84 (1990) and Rietschel et al., supra). These
molecules are of interest because both lipid X and lipid IV.sub.A
display non-pyrogenic characteristics in vitro (Golenbock et al.,
Infect. Immun., 56:779 (1988); Golenbock et al., J. Biol. Chem.,
266:19490 (1991); Wang et al., Infect. Immun., 59(12);4655-4664
(1991); Ulmer et al., Infect Immun., 60(12):145-5152 (1992); Kovach
et al., J. Exp. Med., 172:77-84 (1990); Rietschel et al., supra;
and Raetz, supra). In addition, lipid X and lipid IV.sub.A are LPS
and lipid A antagonists (Wang et al., supra; Ulmer et al., supra;
Kovach et al., supra; Rietschel et al., supra; and Raetz, supra).
The activity of these molecules differs, since lipid X is
non-pyrogenic in mice, whereas lipid IV.sub.A displays similar
toxicity of that of lipid A in mice (Golenbock et al., supra
(1988); Golenbock et al., supra (1991)). Furthermore, CD14 has been
shown to enhance the cellular responses to LPS and lipid IV.sub.A
in mice without imparting ligand-specific recognition (Delude et
al., Proc. Natl. Acad. Sci., 92:9288 (1995)). Together, these
results suggested that individual LPS antagonists may operate
through distinct mechanisms.
[0068] In yet another preferred embodiment of the present
invention, forms of LPS of reduced or absent pyrogenicity isolated
from mutant strains of gram negative bacteria may be used in
accordance with the present invention to treat HIV. There is
growing evidence that mutations in htrB and msbB may influence the
biosynthesis of lipid A. These mutants are temperature sensitive
and LPS isolated from these mutants stains less intensely on
silver-stain gels (Karow et al., J. Bacteriol, 173:741-750 (1991);
Karow and Georgopoulos, J. Bacteriol 174:702-710 (1992)). Although
the basis for the temperature-sensitive growth phenotype of the
htrB and msbB mutants has remained cryptic, there has been
speculation that these mutants produce defective lipid A precursors
(Karow and Georgopoulos, supra). This assumption was based on
altered membrane lipid content (Karow et al., J. Bacteriol.,
174:7407 (1992)). E. coli mutants carrying mutations in htrB, msbB
or both htrB and msbB produce non-pyrogenic LPS when grown at
temperatures above 33.degree. C. and below 44.degree. C. (PCT
International Publication No. WO 97/18837 dated May 29, 1997). This
non-pyrogenic LPS from E. coli mutants carrying mutations in htrB,
msbB or both htrB and msbB also displays LPS antagonist activity
(PCT International Publication No. WO 97/18837). Recent evidence
demonstrated that htrB and msbB function as myristoyl and lauroyl
transferases, respectively and are necessary for the synthesis of
complete lipid A (Clementz et al., J. Biol. Chem., 271:12095
(1996); Summerville et al., J. Clin. Invest., 97:359 (1996).
Collectively, these data suggest that the non-pyrogenic or
reduced-pyrogenic property of LPS isolated from E. coli strains
carrying mutations in htrB, msbB or both htrB and msbB when grown
at temperatures above 33.degree. C. and below 44.degree. C. is the
result of an accumulation of lipid A precursors, such as lipid
IV.sub.A (in htrB, mutants) and penta-acyl lipid A (in the single
msbB mutant).
[0069] Thus, several mutants of E. coli with defective lipid A
biosynthesis have been shown to accumulate LPS and lipid A analogs
with LPS antagonist activity and LPS analogs isolated from these
strains may be used in accordance with the present invention to
treat or prevent HIV infections and disorders associated
therewith.
[0070] In another embodiment of the present invention, LPS
antagonists to be used in accordance with the present invention may
be produced by deacylation of LPS or lipid A. LPS antagonists may
be developed using chemical (Neter et al., J. Immunol., 76:377
(1956); Qureshi et al., J. Biol. Chem., 266:6532 (1991)) or
enzymatic (Munford and Hall, J. Biol. Chem., 264:15613 (1989);
Erwin and Munford, J. Biol. Chem., 256:16444 (1990)) procedures
known to those of ordinary skill in the art. Chemical production of
LPS antagonists from LPS or lipid A can be accomplished by alkaline
hydrolysis of LPS or lipid A (Neter et al., supra; Qureshi et al.,
supra). Enzymatic production of LPS antagonists from LPS or lipid A
can be accomplished by treating LPS or lipid A with acyloxyacyl
hydrolase. A source of acyloxyacl hydrolase are professional
phagocytes which normally produce this enzyme to be utilized by the
host to detoxify LPS (Munford and Hall, supra; Erwin and Munford,
supra).
[0071] In another embodiment, LPS and lipid A compositions of
reduced or absent pyrogenicity which may be used in accordance with
the present invention may be isolated from bacteria such as
Rhodobacter sphaeroides that have LPS with reduced pyrogenicity.
Not all gram negative bacteria produce LPS structures that display
endotoxin activity (Salimath et al., Qureshi et al., J. Biol.
Chem., 266:6532 (1991); Qureshi et al., J. Biol. Chem., 263:5502
(1988)). LPS structures which have significantly less pyrogenicity
than LPS isolated from E. coli, e.g., if the LPS structure
stimulates significantly less or no secretion of IL-1.beta., L-6 or
TNF.alpha. from peripheral blood monocytes (PBMCs), the LPS
structure may be used in accordance with the present invention. For
example, but not by way of limitation, Rhodobacter sphaeroides LPS
has an unusual pentaacyl structure that is significantly less
pyrogenic that E. coli LPS in vitro and in vivo (Salimath et al.,
Eur. J. Biochem., 136:195 (1983); Qureshi et al., J. Biol. Chem.,
266:6532 (1991). Monophosphoryl or diphosphoryl RSLA can also be
used in accordance with the present invention. Moreover, R.
sphaeroides lipid A (RSLA) is an effective LPS antagonist (Salimath
et al., Eur. J. Biochem., 136:195 (1983); Qureshi et al., J. Biol.
Chem., 266:6532 (1991); Qureshi et al., J. Biol. Chem., 263:5502
(1988)) and prevents LPS induced lethality in mice (Salimath et
al., Eur. J. Biochem., 136:195 (1983); Qureshi et al., J. Biol.
Chem., 266:6532 (1991); Qureshi et al., J. Biol. Chem., 263:5502
(1988)). In a further embodiment of the present invention,
monophosphoryl RSLA may be a more effective LPS antagonist than
diphosphoryl RSLA and therefore is used in accordance with an
embodiment of the present invention for the treatment of HIV
(Salimath et al., Eur. J. Biochem., 136:195 (1983); Qureshi et al.,
J. Biol. Chem., 266:6532 (1991); Qureshi et al., J. Biol. Chem.,
263:5502 (1988)).
[0072] In accordance with the present invention, lipopolysacchrides
and lipid A analogs of reduced or absent pyrogenicity may be
yielded by the modification of naturally occurring
lipopolysaccharides. Such modification can include, but are not
limited to treating the lipopolysaccharide or lipid A with
acyloxyacyl hydrolase, or by an alkaline hydrolysis process or a
deacylation process.
[0073] In yet a further embodiment of the present invention,
synthetic LPS antagonists may be used in accordance with the
present invention for the treatment of HIV. For example, but not by
way of limitation, synthetic lipid A and lipid X analogs (Ulmer et
al., Infect. Immun, 60:5145 (1992); Perera et al., Infect Immun.,
61:2015 (1993); Wang et al., Infect. Immun., 59:4655 (1991); Kotani
et al., Infect. Immuno., 54:673 (1986): Kotani et al., Infect
Immun., 49:225 (1985); Fagan et al., J. Immunol., 153:5230 (1994))
can be used. Disaccharide LPS antagonists, which resemble lipid
IV.sub.A, may also be used in accordance with the present invention
(Ulmer et al., supra; Perera et al., supra); Wang et al., supra;
Kotani et al., supra (1985); Kotani et al., supra (1986)). A second
group of synthetic molecules were designed to be analogs of R.
sphaeroides lipid A and are potent LPS antagonists (Christ et al.,
Science 269:80 (1995); Christ et al., J. Am. Chem. Soc., 116:3637
(1994)) and can be used in accordance with the present invention. A
further set of synthetic LPS antagonists have been described that
are composed of monosaccharide backbones and more closely resemble
lipid X; these can be used in accordance with the present invention
(Perera et al., supra). Collectively, these molecules have proven
to display potent LPS antagonist activity in vitro (Ulmer et al.,
supra; Perera et al., supra); Wang et al., supra; Kotani et al.,
supra (1985); Kotani et al., supra (1986)) and have been evaluated
for safety in humans (Bunnell et al., Crit. Care Med. Suppl.,
23:147 (1995); Bunnell et al., Crit. Care Med. Suppl., 23:A151
(1995)). In a preferred embodiment, synthetic analogs of LPS can be
generated which contain a 2-deoxy-2-aminogluconate residue in place
of the glucosamine-1-phosphate at the reducing end and further bear
a galacturonic acid moiety instead of a phosphate at position
4'.
[0074] In another embodiment of the present invention, the
lipopolysaccharides and lipid A molecules and analogs and
derivatives thereof can be modified in accordance with the present
invention so that they are shortened or condensed, e.g., the carbon
backbone may be shortened to a 5 carbon backbone. Further, the LPS
and lipid A structures of the present invention may be modified so
that one or more or all of the glucosamine residues are substituted
with galactosamine residues. The diphosphoryl LPS and lipid A
structures of the present invention can be converted to either
nonphosphoryl or monophosphoryl LPS and lipid A structures in
accordance with the present invention. The lipid A and LPS
structures of the present invention can be modified to have more or
less charge, e.g., the lipid A or LPS structures can be modified to
be more charged by the addition of amine groups. The lipid A and
LPS structures can further be modified so that they are less
immunogenic, i.e., less recognized by the immune system of the
host. In accordance with the present invention, any modification of
the LPS and lipid A structures of the present invention which
results in a non-pyrogenic or reduced-pyrogenic analog or
derivative, i.e., analogs which exhibit decreased induction
relative to wild-type LPS and lipid A of proinflammatory activity
yet stimulate secretion of .beta. chemokines and are effective for
treatment or prevention of HIV infection can be used. The invention
thus also provides a method of screening LPS and lipid A
derivatives and analogs for anti-immunodeficiency virus activity,
e.g., by assaying them for the ability to inhibit immunodeficiency
virus replication or expression of immunodeficiency virus RNA or
protein or to alleviate symptoms of an immunodeficiency
virus-induced disorder.
[0075] In another embodiment of the present invention, a mixture of
one lipid A or LPS or analog or derivative of the present invention
mixed with at least one other LPS or lipid A structure or analog or
derivative thereof of the present invention can be used to treat or
prevent HIV infections and disorders associated therewith. In
accordance with a specific embodiment of the present invention, a
mixture comprising at least one LPS antagonist with an LPS or lipid
A structure isolated from a gram negative organism, wherein the LPS
antagonist is in molar excess of the LPS or lipid A structure can
be used to treat or prevent HIV infection and disorders associated
therewith.
[0076] The lipopolysaccharides and lipid A molecules and analogs
and derivatives thereof of the present invention may be associated
or conjugated with other molecules. These molecules may be
macromolecular carrier groups including, but not limited to,
lipid-fatty acid conjugates, polyethylene glycol, protein or
carbohydrate. The associated or conjugated molecule may also
provide bifunctionality to the lipopolysaccharide by, for example,
targeting the lipopolysaccharide to a predetermined tissue or cell
type, such as T lymphocytes. The association or conjugation between
the lipopolysaccharide and the other molecule may be the result of
a direct interaction, such as for example, through a chemical bond
or ionic interaction, or alternatively, the association or
conjugation with the other molecule may be through a linking group.
The linking group may be known in the art which serves to link the
lipopolysaccharide, or pharmaceutically acceptable derivative
thereof, with the other molecule. Suitable linking groups include
saccharides, oligosaccharides, peptides, proteins, C.sub.2-20
alkyl, oxyalkylene chains or any other group which does not inhibit
the ability of the lipopolysaccharide of the composition to inhibit
HIV replication. The ability of the lipopolysaccharide components
of the composition to inhibit HIV replication may be determined by
applying assays described in Section 5.3.
[0077] The lipopolysaccharides or pharmaceutically acceptable
derivatives of the present invention may be monosaccharide
precursors of lipid A, such as lipid X, or may be a tetra-acyl
precursor of lipid A, such as lipid IV.sub.A, etc. Competitive
inhibition is typically enhanced by increased valence, as once the
first contact is made, the probability of subsequent contact taking
place is favored thermodynamically. The use of multivalents is
especially useful in blocking low affinity events where high
avidity can compensate. Such may be the case for the lipid A
antagonists of the present invention which are thought to function
by competitively inhibiting LPS from interacting with CD14. In a
specific embodiment, the composition comprises multivalent
monosaccharide precursors of lipid A in order to increase the
potency and/or biological half life of the pharmaceutical. In one
embodiment, lipid X is found in multiple copies on a compound for
use in the invention.
[0078] Multivalent carbohydrates can be prepared using methods
known in the art to prepare a branching complex carbohydrate, which
conceptually resembles a tree in which each branch contains a lipid
A precursor, such as, lipid X. Alternatively, monovalent
carbohydrates can be associated covalently or noncovalently with a
polymer using techniques known in the art (see e.g., Langer et al.,
International Patent Publication No. WO94/03184, published Feb. 17,
1994, which is herein incorporated by reference in its entirety).
The oligosaccharide units of the lipopolysaccharides of the present
invention can be bound directly or through a linking group to the
polymer using known techniques so as to produce a conjugate in
which more than one individual molecule of the oligosaccharide of
each lipopolysaccharide is covalently attached. Suitable linking
groups include, but are not limited to saccharides,
oligosaccharides, peptides, proteins, C.sub.2-20 alkyl, oxalkylene
chains or any other group which does not prevent the
lipopolysaccharide from inhibiting HIV replication. Suitable
polymers are known in the art and include, but are not limited to,
a polyol, a polysaccharide, avidin, lipids, lipid emulsions,
liposomes, a dendrimer, human serum albumin, a protein, polylysine,
dextran, a glycosaminoglycan, cyclodextrin, agarose, sepharose, and
polyacrylamide.
[0079] The lipopolysaccharides or pharmaceutically acceptable
derivatives of the invention may be associated (e.g., ionic
interaction) or conjugated (e.g., covalent linkage) with a ligand
for a cell-surface molecule so as to target the lipopolysaccharides
to tissue or cells expressing these molecules. Such
oligosaccharide-ligand combinations may be through direct
interaction of the oligosaccharide and ligand or indirectly using
linker means known in the art. The oligosaccharide/ligand
combination may be generated by techniques known in the art (See
e.g., Stowell & Lee, 1980, Advances in Carbohydrate Chemistry,
37:225-281) and are generated so as not to inhibit the ability of
the lipopolysaccharide to inhibit HIV infection. The ability of the
lipopolysaccharide/ligand combination to inhibit HIV replication
may routinely be determined applying in vitro assays described in
Section 5.3 herein and known in the art. The ability of the
lipopolysaccharide/ligand combination to bind to the cell-surface
binding partner of the ligand may be determined using techniques
known in the art. The ligand component of the lipopolysaccharide
ligand combination may comprise monoclonal antibody, cell-surface
receptor ligand or other homing molecules for therapeutically
significant targets that are known or may routinely be identified
and isolated and/or generated using techniques known in the art.
Ligands encompassed by this embodiment include, but are not limited
to, CD4-derived peptide bound by gp120 of HIV (from the D1 domain
of CD4 and distinct from the MHC-binding region (see e.g., Sakihama
et al., 1995, PNAS 92:644-648; Ryu et al., 1994, Structure
2:59-74), peptides derived from the extracellular domain of
chemokine receptors (e.g., CC-CXR-5 or fusion) to which the V3 loop
of gp120 binds (Choe et al., 1996, Cell 85:1135-1148; Feng et al.,
1996, Science 272:872-876).
5.2. Synthesis and Isolation of Lipopolysaccharides
[0080] In accordance with the present invention the
lipopolysaccharides, LPS analogs (e.g., antagonists), and lipid A
analogs (e.g., antagonists) of the present invention can be
purified from gram negative microorganisms or produced using
classical organic chemistry synthetic techniques known in the art.
Lipid A and LPS antagonists can be identified by their ability to
interfere or compete with the activities of LPS or lipid A, e.g.,
to competitively inhibit the interaction between LPS and the
cellular receptor for LPS, for example, as reflected by the
inhibition of a biological consequence of such an interaction.
Alternatively, in another embodiment, the lipopolysaccharide
analogs and derivatives of the present invention may be prepared by
enzymatic processes. Some non-pyrogenic forms of LPS and lipid A
are commercially available (e.g., from ICN).
5.2.1 Purification of Lipopolysaccharides from Microorganisms
5.2.1.1 Sources of Lipopolysaccharides
[0081] Native preparations of non-pyrogenic or reduced-pyrogenic
forms of lipid A and LPS may be obtained from a variety of sources.
In accordance with the present invention, a variety of gram
negative strains may be used as the starting material in producing
non-pyrogenic or reduced-pyrogenic forms of LPS and lipid A.
Examples of these strains include, but are not limited to,
Haemophilus influenzae, Escherichia coli, Salmonella enterica,
Klebsiella pneumoniae, Bordella pertussis, Pseudomonas aeruginosa,
Chlamydia psittaci, Rhodobacter spearoides, it and Legionella
pneumophila.
[0082] In accordance with the present invention, the non-pyrogenic
or reduced-pyrogenic LPS and lipid A preparations may be isolated
from gram negative strains carrying mutations in one of the
following genes: kdsA, kdsB, htrB, msbB or both htrB and msbB. The
genetics of lipid A biosynthesis are well described (Raetz, supra;
Raetz, Ann. Rev. Biochem 59:129-170 (1990); and Schnaitman and
Klena, supra). The majority of mutations that prevent the
biosynthesis of lipid A, such as mutations in lpxA, lpxB, kdsA,
kdsB, kdtA, are lethal as the biosynthesis of lipid A is essential
for cell survival (Rick et al., J. Biol. Chem., 252:4904-4912
(1977); Rick and Osborn, J. Biol. Chem., 252:4895-4903 (1977);
Raetz et al., J. Biol. Chem., 260:16080-16088 (1985); Raetz, supra
(1990); Raetz, supra (1993); and Belunis et al., J. Biol. Chem.,
270:27646 (1995)). For the most part, therefore, analysis of these
genes has involved the use of temperature-sensitive mutants, which
only display null phenotypes under non-permissive conditions (Rich
et al., supra; Rich and Osborn, supra; Raetz et al., supra; Raetz,
supra (1990); Raetz, supra (19930; and Belunis et al., supra). When
grown under non-permissive conditions, lpxB, kdsA, kdsB, kdsA
mutants accumulate non-pyrogenic precursor forms of LPS (to about
50% of the total LPS), such as lipid X (also called
2,3-diacyl-glucosamine-1-phosphate) or lipid IV.sub.A (Raetz et
al., supra; Belunis et al., supra).
[0083] Alternatively, non-pyrogenic or reduced-pyrogenic LPS and
lipid A preparations may be isolated from gram negative
microorganisms carrying at least one mutation in the genes encoding
for myristoyl transferase or lauroyl transferase. Gram negative
microorganisms carrying mutations in the pgsA gene, which encodes
phosphatidylglycerophospate synthase; lpxB, the structural gene for
disaccharide synthase; the lpxA gene, encoding UDP-GlcNAc
O-acetyltransferase; kdtA the structural gene encoding the KDO
(3-deoxy-D-manno-actulosonic acid) transferase, may also be used as
a source of non-pyrogenic or reduced-pyrogenic LPS or lipid A
structures in accordance with the present invention.
[0084] In a preferred embodiment of the present invention,
non-pyrogenic forms of LPS may be isolated from strains of E. coli
carrying mutations in both htrB and msbB, which produce
non-pyrogenic LPS when grown at temperatures above 33.degree. C.
and below 44.degree. C. (See PCT International Publication No. WO
97/18837). In a preferred embodiment of the present invention,
non-pyrogenic LPS is isolated from the E. coli htrB1::Tn10
msbB::.OMEGA.cam double mutant MLK986. In yet another preferred
embodiment, non-pyrogenic preparations of lipid A are isolated from
gram negative bacteria KDO-deficient mutants which accumulate lipid
IV.sub.A, a non-pyrogenic form of lipid A (Goldman et al., 1988, J.
Bacteriol. 170:2185-2192; Raetz et al., 1985, J. Biol. Chem.
260:16080-16088).
[0085] Many of the proteins involved in lipid A metabolism are
essential to bacteria vitality and therefore mutations in these
genes must be introduced as ones inducible by growth conditions,
i.e., temperature sensitive mutants, or the mutant genes may be
under the control of an inducible promoter, such as a tetracycline
promoter, tetR, or a repressible promoter, such as a lexA-repressed
promoter. Mutations may be introduced into the genomes of gram
negative bacteria using standard recombinant DNA techniques well
known to those of ordinary skill in the art. Mutations in the
designated genes listed above may consist of the deletion of the
gene or a portion thereof, insertion of nucleic acids into the gene
coding region, missense mutations, nonsense mutations (see, e.g.,
Miller 1992, A Short Course in Bacterial Genetics, Cold Spring
Harbor Press; Sambrook et al., 1989, Molecular Cloning, A
Laboratory Manual, Cold Spring Harbor Laboratory, 2d Ed., Cold
Spring Harbor, N.Y., Glover), etc. Any technique for mutagenesis
known in the art may be used, including but not limited to,
chemical mutagenesis, in vitro site-directed mutagenesis
(Hutchinson, C. et al., 1978, J. Biol. Chem. 253:6551), use of
TAB.TM. linkers (Pharmacia), PCR with mutant primers, etc.
[0086] Further, in vivo cloning techniques can be used to introduce
mutation-containing nucleic acids into the genomes of gram negative
bacteria (see, e.g., Miller 1992, A Short Course in Bacterial
Genetics, Cold Spring Harbor Press; Sambrook et al., 1989,
Molecular Cloning, A Laboratory Manual, Cold Spring Harbor
Laboratory, 2d Ed., Cold Spring Harbor, N.Y., Glover), etc.
[0087] Other bacterial strains may be used in accordance with the
present invention as a source of forms of LPS and lipid A of
reduced or absent pyrogenicity. For example, Rhodobacter
sphaeroides LPS has an unusual pentaacyl structure that is
significantly less pyrogenic than E. coli LPS in vitro and in vivo
(Salimath et al. supra; Qureshi et al. supra, 1991; Qureshi et al.
supra 1988). R. sphaeroides lipid A (RSLA) is an effective LPS
antagonist (Salimath et al. supra) and prevents LPS induced
lethality in mice. Bacterial strain Rhizobium leguminosarum may
also be used as a source of non-pyrogenic form of LPS and lipid A,
in accordance with the present invention. Lipid A isolated from R.
leguminosarum lacks phosphate altogether and does not contain a
glucosamine disaccharide (Bhat et al. 1992 Glycobiology 2:535-539)
and is a very potent antagonist of lipid A. R. leguminosarum lipid
A contains a 2-deoxy-2-aminogluconate residue in place of the
glucosamine 1-phosphate at the reducing end, and bears a
glacturonic acid moiety instead of a monophosphate at position
4'.
5.2.1.2 Isolation of Lipopolysaccharides
[0088] The lipopolysaccharides of the present invention may be
purified from gram negative microorganisms using any technique
known in the art. In this embodiment, the lipopolysaccharides of
the present invention are isolated from the cell wall of the
bacteria. In gram-negative bacteria, the cell wall is far more
complex than for gram positives and contains glycopeptide,
lipopolysaccharide, phospholipid and protein. Up to 20% of the wall
contents may be lipids but only a proportion of these are readily
extractable by conventional solvent methods. That is due to the
covalent nature of the lipopolysaccharide linkages. In spite of the
foregoing, in accordance with the present invention, the
lipopolysaccharides of the present invention may be isolated from
gram-negative bacteria using the procedures described infra.
[0089] By way of example, and not by limitation, the
lipopolysaccharides of the present invention may be isolated by the
following method:
[0090] Bacterial strains are cultured on solid media both at
30.degree. C., 37.degree. C. or 42.degree. C. prior to seeding the
liquid media. Liquid cultures (1L) are seeded the following day at
a starting inoculum of ca. 1.times.10.sup.4 cfu/ml and grown for 16
hr at 30.degree. C., 37.degree. C. or 42.degree. C. with shaking
(250 opm).
[0091] The liquid cultures are harvested by centrifugation at
7000.times.g for 10 min, washed once in 250 ml endotoxin-free
irrigation saline (Baxter) and the weight of the bacterial pellets
was determined. The pellets then are resuspended in endotoxin-free
water (Baxter) at a final density of 2% w/v 0.25%. Subsequently,
LPS is isolated by two cycles of hot-water phenol extraction. In
short, the bacterial suspensions are heated to 70.degree. C. to
which an equal volume of pre-warmed phenol is added and mixed for
15 min at 70.degree. C. The mixtures are cooled to 25.degree. C.
and then centrifuged at 18,000.times.g for 15 min. Following this
centrifugation the aqueous phases are removed, placed into dialysis
tubing (SpectraPor) and dialyzed against running distilled H.sub.2O
overnight. The retentates are then placed into fresh 50 ml
polypropylene tubes and treated with RNaseA (100 .mu.g/ml) at
37.degree. C. for 1 hr, followed by DNaseI (50 .mu.g/ml and 5 mM
MgCl.sub.2) at 37.degree. C. for 1 hr, followed by Pronase (250
.mu.g/ml) at 37.degree. C. for 1 hr. Then EDTA is added to a final
concentration of 5 mM and the hot-water phenol extraction procedure
described above is repeated. Following dialysis the retentates are
centrifuged at 20,000.times.g for 15 min at 4.degree. C. The
supernatants are transferred to fresh Beckman 50Ti tubes and the
LPS is pelleted by centrifugation at 110,000.times.g for 2H at
4.degree. C. The supernatants are discarded and the pellets are
vacuum dried. Each LPS preparation is evaluated for DNA and protein
contamination by standard techniques in the art, such as SDS-PAGE
and silver stain, BCA protein estimate assay and UV
spectrophotometry.
[0092] Also included within the scope of the present invention are
LPS and lipid A molecules which are differentially modified during
or after synthesis to yield reduced or absent pyrogenic properties
of the preparation. In specific embodiments, the LPS and lipid A
molecules are treated by alkaline hydrolysis or acyloxyacyl
hydrolase. Any of numerous chemical modifications may be carried
out by known techniques, such as acylation, deacylation,
formylation, oxidation, reduction, etc.
5.2.2 Synthesis of Lipopolysaccharides
[0093] Potent synthetic lipid A molecules with strong LPS
antagonist properties and of reduced or absent pyrogenicity may be
synthesized by a variety of organic chemistry synthetic techniques.
In one embodiment of the present invention, the synthetic lipid A
and LPS molecules are modeled after LPS molecules of reduced or
absent pyrogenicity which occur in nature and molecules with strong
LPS antagonist activities which occur in nature.
[0094] The lipopolysaccharide is a complex polymer in four parts.
Outermost is a carbohydrate chain variable length (called the
O-antigen) which is attached to a core polysaccharide. The core
polysaccharide is divided into the outer core and the backbone.
These two structures vary between bacteria. Finally the backbone is
attached to a glycolipid called lipid A. The link between lipid A
and the rest of the molecule is usually via a number of
3-deoxy-D-manno-octulosonic acid (KDO) molecules. The presence of
KDO is often used as a marker for lipopolysaccharide (or outer
membrane) even though it is not present in all bacterial
lipopolysaccharides. The phosphate and 3-deoxy-D-mannooctulosomic
acid (KDO) molecules (the presence of KDO is often used as a marker
for lipopolysaccharide) are also substituted. Unsaturated and
cyclopropane fatty acids which are common in other lipid types are
absent from lipopolysaccharide.
[0095] Lipid A is composed of a disaccharide of glucosamines. The
amino groups are substituted with 3-hydroxymristate while hydroxyl
groups contain saturated (12-16 carbon) acids and
3-myristoxymyristate. Lipopolysaccharides and lipid A may be
obtained from commercial sources, e.g., from Sigma. However, by way
of example, but not by way of limitation, lipolysaccharides may be
synthesized as follows: hydroxy acids and disaccharides are
condensed followed by addition of saturated fatty acids. The
hydroxy fatty acids may come from acetyl CoA whereas CMP-KDO may
serve as the source of the second additional units. After the
addition of saturated fatty acids, sugars are added from nucleotide
diphosphate derivatives.
[0096] The O-antigen is may be synthesized in three stages. For
example, but not by way of limitation, the oligosaccharide units
are transferred from nucleotide diphosphate carriers to a galactose
attached to another lipid carrier. The oligosaccharide units are
then polymerized and lipid carriers are released in the process.
Finally the complete O-antigen is transferred to the R-core with
the release of an isoprenoid carrier.
[0097] For an overview of the synthesis of lipopolysaccharides and
lipid A structures, see, e.g., Raetz, 1993, J. Bacteriology
175:5745-5753. (See also U.S. Pat. Nos. 5,593,969 and
5,191,072).
[0098] The polysaccharide unit may also be synthesized with donor
saccharide moieties and acceptor moieties which are commercially
available and/or may be synthesized through organic synthesis
applying techniques known in the art. Activated saccharides
generally consist of uridine or guanosine diphosphate and cytidine
monophosphate derivatives of the saccharides in which the
nucleoside mono and diphosphate serves as a leaving group. Thus,
the activated saccharide may be a saccharide-UDP, a saccharide-GDP,
or a saccharide-CMP. Nucleoside monophosphates are commercially
available, may be prepared from known sources such as digested
yeast RNA (see e.g., Leucks et al,. 1979, J. Am. Soc. 101:5829), or
routinely prepared using known chemical synthetic techniques (see
e.g., Heidlas et al., 1992, Acc, Chem. Res. 25:307; Kochetkov et
al., 1973, Adv. Carbohydr. Chem. Biochem. 28:307). These nucleoside
monophosphates may then be routinely transformed into nucleoside
diphosphates by kinase treatment. For review, see Wong et al.,
1994, Enzymes in Synthetic Organic Chemistry, Pergamon Press,
Volume 12, pp. 256-264.
[0099] Glycosyltransferase enzymes for synthesizing the
compositions of the invention can be obtained commercially or may
be derived from biological fluids, tissue or cell cultures. Such
biological sources include, but are not limited to, pig serum and
bovine milk. Glycosyltransferases that catalyze specific glycosidic
linkages may routinely be isolated and prepared as described in
International Patent Publication No. WO 93/13198 (published Jul. 8,
1993). Alternatively, the glycosyltransferases can be produced
through recombinant or synthetic techniques known in the art (For
review, see Wong et al., 1994, Enzymes in Synthetic Organic
Chemistry, Pergamon Press, Volume 12, pp. 275-279).
[0100] The compositions of the invention are preferably synthesized
using enzymatic processes (see U.S. Pat. No. 5,189,674, and
International Patent Publication No. 91/16449, published Oct. 31,
1991). Briefly, a glycosyltransferase is contacted with an
appropriate activated saccharide and an appropriate acceptor
molecule under conditions effective to transfer and covalently bond
the saccharide to the acceptor molecule. Conditions of time,
temperature, and pH appropriate and optimal for a particular
saccharide unit transfer can be determined through routine testing;
generally, physiological conditions will be acceptable. Certain
co-reagents may also be desirable; for example, it may be more
effective to contact the glycosyltransferase with the activated
sugar and the acceptor molecule in the presence of a divalent
cation. Optionally, an apparatus as described by U.S. Pat. No.
5,288,637, is used to prepare such compositions.
[0101] While glycosyltransferases are highly stereospecific and
substrate-specific, minor chemical modifications are tolerated on
both the donor and acceptor components. Accordingly, the
oligosaccharide components of the invention may be synthesized
using acceptor and/or donor components that have been modified so
as not to interfere with enzymatic formation of the desired
glycosidic linkage. The ability of such a modification not to
interfere with the desired glycosidic linkage may routinely be
determined using techniques and bioassays known in the art, such
as, for example, labelling the carbohydrate moiety of the activated
sugar donor, contacting the acceptor and donor moieties with the
glycosyltransferase specific for forming the glycosidic linkage
between the donor and acceptor moieties, and determining whether
the label is incorporated into the molecule containing the acceptor
moiety.
[0102] Also included within the scope of the present invention are
LPS and lipid A molecules which are differentially modified during
or after synthesis to enhance or yield of reduced or absent
pyrogenicity of the preparation. In specific embodiments, the LPS
and lipid A molecules are treated by alkaline hydrolysis or
acyloxyacyl hydrolase. Any of numerous chemical modifications may
be carried out by known techniques, such as acylation, deacylation,
formylation, oxidation, reduction, etc.
[0103] It is also within the scope of this invention, to synthesize
analogs of lipid a having one or more acyloxyacyl groups removed.
Lipid A, either chemically synthesized or isolated from a gram
negative microorganism may be treated with acyloxyacyl hydrolase in
order to achieve or enhance the non-pyrogenic properties of the
preparation. Acyloxyacyl hydrolase hydrolyzes the ester bonds
between non-hydroxylated fatty acids and the 3-hydroxy functions of
3-hydroxy fatty acids bound in ester or amide linkages to
glucosamine disaccharide of lipid A.
[0104] It is further within the scope of this invention, to
synthesize analogs of lipid A and LPS having one or more
non-hydroxylated fatty acids removed. Lipid A or LPS either
chemically synthesized or isolated from a gram negative
microorganism may be deacylated in order to achieve or enhance the
substantially reduced or absent pyrogenicity of the
preparation.
5.3 Therapeutic Uses
[0105] The invention provides for treatment or prevention of
diseases and disorders associated with immunodeficiency virus
infection, including, but not limited to, human immunodeficiency
virus (HIV), simian immunodeficiency virus (SIV), and feline
immunodeficiency virus (FIV), by administration of a therapeutic
compound (termed herein "Therapeutic"). Such "Therapeutics"
include, but are not limited to: preparations of LPS or lipid A of
reduced or absent pyrogenicity, and analogs and derivatives and
antagonists thereof, of reduced or absent pyrogenicity. By way of
example, but not limitation, the antagonists can be derived from
gram negative bacteria, or gram-negative bacteria containing at
least one mutation selected from the group consisting of kdsA,
kdsB, htrB, msbB and derivative and analogs of the foregoing; LPS
or lipid A preparations which have been modified to enhance or
yield reduced or absent pyrogenicity, including, but not limited to
monophosphoryl lipid A, penta-acyl lipid A, lipid X, lipid
IV.sub.A, or lipid A or LPS derived from deacylation, treatment
with acyloxyacyl hydrolase, or by treatment with an alkaline, and
derivatives and analogs of the foregoing; synthetic lipid A and LPS
antagonists, such as lipid X, lipid IV.sub.A and prophylactically
and therapeutically effective LPS and lipid A analogs and
derivatives thereof.
[0106] It is also within the scope of this invention, to use
therapeutically or prophylactically monosaccharide analogs of lipid
A and LPS. Lipid A or LPS structures to be used therapeutically or
prophylactically in accordance with the present invention can be
either chemically synthesized or isolated from a gram negative
microorganism, in which the ester bond of LPS and lipid A is
catalyzed or the glycosidic bond of LPS and lipid A is catalyzed
resulting in a monosaccharide derivative with enhanced
non-pyrogenic properties.
[0107] It is also within the scope of this invention, to use
mixtures of lipid A or LPS structures and antagonists and analogs
and derivatives thereof therapeutically or prophylactically in
accordance with the present invention.
[0108] In another embodiment of the present invention, a mixture of
one lipid A or LPS structure of the present invention mixed with at
least one other LPS or lipid A structure of the present invention
can be used to treat or prevent immunodeficiency virus infection,
including HIV infections and disorders associated therewith. In
accordance with the present invention, a mixture comprising at
least one LPS antagonist and an LPS or lipid A structure isolated
from a gram negative bacteria, wherein the LPS antagonist is in
molar excess of the LPS or lipid A structure can be used to treat
or prevent HIV infection and disorders associated therein. For
example, an LPS or lipid A antagonist combined with a fully active
LPS or lipid A, or a monophosphate LPS or lipid A, or a second LPS
or lipid A antagonist.
[0109] Examples of Therapeutics are those lipopolysaccharides
described in Section 5.1 and 5.2.
[0110] A preferred embodiment of the invention relates to methods
of using a Therapeutic for treatment or prevention of HIV
infection, preferably HIV-1 infection, in a human subject. In a
specific embodiment, the Therapeutic is used for the treatment or
prevention of HIV infection in a human subject who suffers from
Kaposi's sarcoma (KS). In the treatment of HIV infection, the
Therapeutic of the invention can be used to prevent progression of
HIV-1 infection in a seropositive patient to ARC or to AIDS in the
patient, or to treat a human patient with ARC or AIDS.
[0111] In a preferred aspect of the invention, preparations of
reduced or absent pyrogenicity of LPS and/or lipid A and/or
derivatives and/or analogs thereof are used to treat HIV infection.
The utility of such preparations may be determined by the in vitro
and in vivo assays described in Section 5.5 infra or by any other
method known in the art.
[0112] 5.4 Combination Therapy
[0113] According to a specific embodiment of the present invention,
a preparation of reduced or absent pyrogenicity of LPS or lipid A
or an analog or derivative thereof, an inhibitor of HIV viral
replication, may optionally be used in combination with other
therapeutic agents to enhance the antiviral effect achieved.
Preferably a non-pyrogenic preparation of LPS or lipid A or an
analog or derivative thereof is used in combination with another
antiviral agent. Such additional antiviral agents which may be used
with a preparation of reduced or absent pyrogenicity of LPS or
lipid A or analog or derivative thereof include but are not limited
to those which function on a different target molecule involved in
viral replication, e.g., reverse transcriptase inhibitors, viral
protease inhibitors, glycosylation inhibitors; those which act on a
different target molecule involved in viral transmission; those
which act on a different loci of the same molecule; and those which
prevent or reduce the occurrence of viral resistance. One skilled
in the art would know of a wide variety of antiviral therapies that
exhibit the above modes of activity.
[0114] A preparation of reduced or absent pyrogenicity of LPS or
lipid A or an analog or derivative thereof can also be used in
combination with retrovirus inhibitors, such as nucleoside
derivatives. Nucleoside derivatives are modified forms of purine
and pyrimidine nucleosides that are the building blocks of RNA and
DNA. Many of the nucleoside derivatives under study as potential
anti-HIV medications result in premature termination of viral DNA
replication before the entire genome has been transcribed. These
derivatives lack 3' substituents that can bind to subsequent
nucleosides and result in chain termination. Nucleoside derivatives
such as 3' azido-3'-thymidine (AZT) and dideoxyinosine (ddI) have
been exploited as inhibitors of HIV-1 replication, both in vitro
and in vivo. Nucleoside analogs are currently the only licensed
therapeutics for the treatment of HIV infection and AIDS (Fischl et
al., 1987 N. Engl. J. Med. 317, 185-191; Mitsuya and Broder, 1987
Nature 325, 773-778). This class of compounds works by inhibiting
reverse transcriptase resulting in a block in cDNA synthesis
(Mitsuya and Broder, 1987), these inhibitors work early in the
infectious cycle of HIV-1 and inhibit integration into T-cell
genome. However, AZT therapy leads to development of resistant HIV
strains (Larder 1989, 1991, Ibid.) and demonstrates toxicity in
AIDS patients upon long-term therapy (Fischl et al., 1987, N. Engl.
J. Med. 317:185-191; Creagh-Kirk, et al., 1988, J.A.M.A.
260:3045-3048).
[0115] Further, a preparation of reduced or absent pyrogenicity of
LPS or lipid A or a derivative or analog thereof can be used in
combination with nucleoside derivatives which include but are not
limited to, 2',3'-dideoxyadenosine (ddA); 2',3'-dideoxyguanosine
(ddG); 2',3'-dideoxyinosine (ddI); 2',3'-dideoxycytidine (ddC);
2',3'-dideoxythymidine (ddT); 2',3'-dideoxy-dideoxythymidine (d4T)
and 3'-azido-2',3'-dideoxythymidine (AZT). Alternatively,
halogenated nucleoside derivatives may be used, preferably
2',3'-dideoxy-2'-fluoronuc- leosides including, but not limited to,
2',3'-dideoxy-2'-fluoroadenosine; 2',3'-dideoxy-2'-fluoroinosine;
2',3'-dideoxy-2'-fluorothymidine; 2',3'-dideoxy-2'-fluorocytosine;
and 2',3'-dideoxy-2',3'-didehydro-2'-flu- oronucleosides including,
but not limited to 2',3'-dideoxy-2',3'-didehydro-
-2'-fluorothymidine (Fd4T). Preferably, the
2',3'-dideoxy-2'-fluoronucleos- ides of the invention are those in
which the fluorine linkage is in the beta configuration, including,
but not limited to, 2'3'-dideoxy-2'-beta-fluoroadenosine (F-ddA),
2',3'-dideoxy-2'-beta-fluor- oinosine (F-ddI), and
2',3'-dideoxy-2'-beta-fluorocytosine (F-ddC). Such combinations
allow one to use a lower dose of the nucleoside derivative thus
reducing the toxicity associated with that agent, without loss of
antiviral activity because of the use of the non-pyrogenic
preparation of LPS or lipid A. Moreover, such a combination reduces
or avoids viral resistance.
[0116] Preferred combinations of preparations of reduced or absent
pyrogenicity of LPS or lipid A or derivatives or analogs thereof
and nucleoside derivatives within the scope of the present
invention include an effective amount of a preparation of reduced
or absent pyrogenicity of LPS or lipid A or analogs or derivatives
thereof and an effective amount of AZT to treat HIV infection; and
an effective amount of a preparation of reduced or absent
pyrogenicity of LPS or lipid A or derivative and analogs thereof
and an effective amount of ddI.
[0117] According to the present invention, preparations of reduced
or absent pyrogenicity of LPS or lipid A or derivatives and analogs
thereof can also be used in combination with uridine phosphorylase
inhibitors, including but not limited to acyclouridine compounds,
including benzylacyclouridine (BAU); benzyloxybenzylacyclouridine
(BBAU); aminomethyl-benzylacyclouridine (AMBAU);
aminomethyl-benzyloxybenzylacycl- ouridine (AMB-BAU);
hydroxymethyl-benzylacyclouridine (HMBAU); and
hydroxymethyl-benzyloxybenzylacyclouridine (HMBBAU).
[0118] According to the present invention, preparations of reduced
or absent pyrogenicity of LPS or lipid A or derivatives and analogs
thereof can be used in combination with viral protease inhibitors,
including but not limited to, Invirase (saquinavir, Roche), ABT-538
(Abbott, CAS Reg. No. 155213-67-5), AG1343 (Burroughs
Wellcome/Glaxo, CAS Reg. No. 161814-49-9). Protease inhibitors are
generally thought to work primarily during or after assembly (i.e.,
viral budding) to inhibit maturation of virions to a mature
infectious state. For example, ABT-538 has been shown to have
potent antiviral activity in vitro and favorable pharmokinetic and
safety profiles in vivo (Ho, et al., 1995, Nature 373: 123-126).
Administration of ABT-538 to AIDS patients causes plasma HIV-1
levels to decrease exponentially and CD4 lymphocyte counts to rise
substantially. The exponential decline in plasma viraemia following
ABT-538 treatment reflects both the clearance of free virions and
the loss of HIV-1 producing cells as the drug substantially blocks
new rounds of infection. ABT-538 treatment reduces virus-mediated
destruction of CD4 lymphocytes. Combining this treatment with a
preparation of reduced or absent pyrogenicity of LPS or lipid A or
an analog or derivative thereof, which inhibits at an earlier stage
of HIV infection, viral fusion, would be likely to have synergistic
effects and have a dramatic clinical impact.
[0119] In order to evaluate potential therapeutic efficacy of
reduced-pyrogenic or non-pyrogenic preparations of LPS or lipid A
or derivatives and analogs thereof in combination with the
antiviral therapeutics described above, these combinations may be
tested for antiviral activity according to methods known in the
art.
[0120] A compound of the invention can be administered to a human
patient by itself or in pharmaceutical compositions where it is
mixed with suitable carriers or excipients at doses to treat or
ameliorate various conditions involving HIV-infection. A
therapeutically effective dose further refers to that amount of the
compound sufficient to inhibit HIV infection. Therapeutically
effective doses may be administered alone or as adjunctive therapy
in combination with other treatments for HIV infection or
associated diseases. Techniques for the formulation and
administration of the compounds of the instant application may be
found in "Remington's Pharmaceutical Sciences" Mack Publishing Co.,
Easton, Pa., latest addition.
[0121] In another embodiment, HIV infection is treated or prevented
by administration of a Therapeutic of the invention in combination
with one or more chemokines. In particular, the Therapeutic is
administered with one or more C-C type chemokines, especially one
or more from the group RANTES, MIP-1.alpha. and MIP-1.beta..
5.5 Demonstration of Therapeutic Utility
[0122] The present invention relates to assaying the therapeutic
compounds of the present invention for their therapeutic
effectiveness, including assaying their pyrogenicity properties in
addition to their anti-HIV properties.
[0123] Such assays include, but are not limited to:
5.4.1 Determining the Pyrogenicity of the Preparation
[0124] The Therapeutics of the invention are preferably tested in
vitro, and then in vivo for non-pyrogenicity or reduced
pyrogenicity, prior to use in humans. Any in vitro or in vivo assay
known in the art to measure pyrogenic, inflammatory or endotoxic
activity can be used to test the pyrogenicity of a Therapeutic of
the invention. By way of example, and not by way of limitation, one
could use any of the in vitro assays described infra in Section
6.
[0125] In an embodiment of the invention, a method of screening a
preparation comprising LPS or lipid A or a derivative or analog
thereof for pyrogenic properties comprises assaying said
preparation for the ability to induce secretion of pyrogenic
cytokines. In one specific embodiment, the preparation comprising
LPS or lipid A or a derivative or analog thereof is assayed by a
method comprising measuring cytokine levels secreted from
peripheral blood monocytes, which cells have been contacted with
the preparation and comparing to levels of cytokines secreted from
cells not contacted with the preparation and/or levels of cytokines
secreted from cell contacted with E. coli LPS (known to be highly
pyrogenic). Quantitation of TNF.alpha., IL-1.beta. or IL-6 in
culture supernatants can be achieved by capture ELISA. In another
specific embodiment, the preparation comprising LPS or lipid A or a
derivative or analogue thereof is assayed by a method comprising
measuring .beta. chemokine levels secreted from peripheral blood
monocytes, which cells have been contacted with the preparation and
comparing to levels of .beta. chemokines secreted from cells not
contacted with the preparation and/or levels of chemokines secreted
from cells contacted with E. coli LPS. Quantitation of
MIP-1.alpha., MIP-1.beta. and RANTES in culture supernatants can be
achieved by capture ELISA.
[0126] The assays described above may be carried out by any method
known in the art. By example, and not by limitation, the assays
described above may be carried out as follows:
[0127] 50 ml of whole blood is mixed with an equal volume of RPMI
(Life Technologies) and PBMCs are isolated by density gradient
using lymphocyte separation medium according to the manufacturer's
directions (Organon). The PBMCs are washed twice with RPMI then
resuspended in 6 ml of ice cold sterile water and placed on ice for
30 sec to lyse the erythrocytes. The osmolarity is adjusted by
adding 2 ml of ice cold 3.5% (w/v) NaCl; the PBMCs are harvested by
centrifugation, washed with RPMI and resuspended in complete medium
(CM; RPMI containing pyruvate, glutamine, PenStrep, and 10%
endotoxin-free human AB serum (Life Technologies) at a density of
6.times.10.sup.6 PBMCs/ml. CM containing the preparations to be
assayed are placed into duplicate wells of a 96-well flat bottom
culture late (Costar) at double the target final concentration. An
equal volume of CM containing the PBMCs then is added to these
wells and the culture plates are incubated at 37 C in 5% CO.sub.2
for 8 hr. The supernatants are then removed and stored at
70.degree. C. Quantitation of TNF.alpha., IL-1.beta., IL-6,
MIP-1.alpha., MIP-1.beta. and RANTES in these culture supernatants
is achieved by capture ELISA (R&D Systems).
[0128] The Therapeutics of the invention may also be tested in vivo
for non-pyrogenicity prior to use in humans. For example, pyrogenic
activity may be measured in vivo by a dermal Schwartzman reaction
and the rabbit pyrogen test. By way of example but not limitation,
this is performed as follows: New Zealand rabbits may receive an
intradermal injection of the preparation of LPS or lipid A or a
derivative or analog thereof (approximately 2.5 .mu.g), followed by
an intravenous dose (2-4 .mu.g/kg) 24 hours later. The dermal
lesions are scored 4 to 6 hours later and compared to rabbits that
received an infection of a preparation of LPS from E. coli. The
therapeutics of the invention may also be determined by the rabbit
pyrogen test. The thermal response index (TRI) for LPS preparations
is determined by injecting a New Zealand white rabbit weighing 3-4
kg with an intravenous dose of approximately 50 ng LPS. Temperature
is monitored with a rectal probe and recorded every 10 minutes. The
TRI is the integrated product of the temperature above baseline (0
C) and time (degree-hours) (Zimmer et al., 1981 Peptides
2:413).
5.4.2 Determining the Anti-HIV Activity of the Preparation
[0129] The Therapeutics of the invention are preferably tested in
vitro, and then in vivo for the desired therapeutic or prophylactic
activity, prior to use in humans. Any in vitro or in vivo assay
known in the art to measure HIV infection or production can be used
to test the efficacy of a Therapeutic of the invention. By way of
example, and not by way of limitation, one could use any of the in
vitro or in vivo assays described infra in Section 6.
[0130] In an embodiment of the invention, a method of screening a
preparation comprising a lipopolysaccharide, i.e. lipid A or LPS or
lipid A antagonist or LPS antagonist, having non-pyrogenic
properties or any derivative or analogue thereof, for anti-HIV
activity is provided, which assay comprises assaying said
preparation for the ability to inhibit HIV replication or
expression of HIV RNA or protein. In one specific embodiment, the
lipopolysaccharide preparation is assayed by a method comprising
measuring HIV-1 p24 antigen levels in cultured hematopoietic cells
which have been contacted with the lipopolysaccharide preparation
prior to infection with HIV-1, and comparing the measured HIV-1 p24
antigen levels in the cells which have been contacted with the
lipopolysaccharide preparation with said levels in cells not so
contacted with the preparation, wherein a lower level in said
contacted cells indicates that the preparation has anti-HIV
activity. In another specific embodiment, the lipopolysaccharide
preparation is assayed by a method comprising measuring the
activity of a reporter gene product expressed from a construct in
which the HIV-1 LTR is operably linked to said reporter gene,
wherein said construct is present in cells which have been
contacted with the preparation; and comparing the measured
expression of said reporter gene in the cells which have been
contacted with the preparation with said levels in such cells not
so contacted, wherein a lower level in said contacted cells
indicates that the preparation has anti-HIV activity. In another
specific embodiment, the lipopolysaccharide preparation is assayed
by a method comprising measuring HIV-1 derived RNA transcripts or
HIV-1 antigen levels in HIV-1 transgenic mice administered the
preparation; and comparing the measured transcript or antigen
levels in the mice which have been administered the preparation
with said levels in mice not so administered, wherein a lower level
in said administered mice indicates that the preparation has
anti-HIV activity. In yet another specific embodiment, the
lipopolysaccharide preparation is assayed by a method comprising
measuring SIV p27 antigen levels in the peripheral blood
mononuclear cells of SIV infected monkeys administered the
preparation; and comparing the measured antigen levels in the
monkeys which have been exposed to the preparation with said levels
in monkeys not so administered, wherein a lower level in said
administered monkeys indicates that the preparation has anti-HIV
activity.
[0131] By way of example, to assay a Therapeutic in vitro, one can
examine the effect of the Therapeutic on HIV replication in
cultured cells. Briefly, cultured hematopoietic cells (e.g.,
primary PBMCs, isolated macrophages, isolated CD4.sup.+ T cells or
cultured H9 human T cells) are acutely infected with HIV-1 using
titers known in the art to acutely infect cells in vitro, such as
10.sup.5 TCID.sub.50/ml. Then, appropriate amounts of the
Therapeutic are added to the cell culture media. Cultures are
assayed 3 and 10 days after infection for HIV-1 production by
measuring levels of p24 antigen using a commercially available
ELISA assay. Reduction in p24 antigen levels over levels observed
in untreated controls indicates the Therapeutic is effective for
treatment of HIV infection.
[0132] Additionally, assays for HIV-1 LTR driven transcription are
useful for testing the efficacy of Therapeutics of the invention.
Specifically, a reporter gene, i.e., a gene the protein or RNA
product of which is readily detected, such as, but not limited to,
the gene for chloramphenicol acetyltransferase (CAT), is cloned
into a DNA plasmid construct such that the transcription of the
reporter gene is driven by the HIV-1 LTR promoter. The resulting
construct is then introduced by transfection, or any other method
known in the art, into a cultured cell line, such as, but not
limited to, the human CD4.sup.+ T cell line HUT78. After exposure
of the transformed cells to the Therapeutic, transcription from the
HIV-1 LTR is determined by measurement of CAT activity using
techniques which are routine in the art. Reduction in HIV-1 LTR
driven transcription demonstrates utility of the Therapeutic for
treatment and/or prevention of HIV infection.
[0133] Exemplary tests in animal models are described briefly as
follows: First, a Therapeutic of the invention is administered to
mice transgenic for HIV-1, e.g., mice which have integrated
molecular clone pNL4-3 containing 7.4 kb of the HIV-1 proviral
genome deleted in the gag and pol genes (Dickie, P., et al., 1991,
Virology 185:109-119). Skin biopsies taken from the mice are tested
for HIV-1 gene expression by RT-PCR (reverse
transcription-polymerase chain reaction) or for HIV-1 antigen
expression, such as expression of gp120 or NEF, by immunostaining.
Additionally, the mice are examined for reduction in the cachexia
and growth retardation usually observed in HIV-1 transgenic mice
(Franks, R. R., et al., 1995, Pediatric Res. 317:56-63).
[0134] The efficacy of Therapeutics of the invention can also be
determined in SIV infected rhesus monkeys (see Letrin, N. L., and
King, N. W., 1990, J. AIDS 3:1023-1040), particularly rhesus
monkeys infected with SIV.sub.mac251, which SIV strain induces a
syndrome in experimentally infected monkeys which is very similar
to human AIDS (Kestler, H., et al., 1990, Science 248:1109-1112).
Specifically, monkeys can be infected with cell free
SIV.sub.mac251, for example, with virus at a titer of 10.sup.4.5
TCID.sub.50/ml. Infection is monitored by the appearance of SIV p27
antigen in PBMCs. Utility of the Therapeutic is characterized by
normal weight gain, decrease in SIV titer in PBMCs and an increase
in CD4.sup.+ T cells.
[0135] Once the Therapeutic has been tested in vitro, and also
preferably in a non-human animal model, the utility of the
Therapeutic can be assayed in human subjects. The efficacy of
treatment with a Therapeutic can be assessed by measurement of
various parameters of HIV infection and HIV associated disease.
Specifically, the change in viral load can be determined by
quantitative assays for plasma HIV-1 RNA using quantitative RT-PCR
(Van Gemen, B., et al., 1994, J. Virol. Methods 49:157-168; Chen,
Y. H., et al., 1992, AIDS 6:533-539) or by assays for viral
production from isolated PBMCs. Viral production from PBMCs is
determined by co-culturing PBMCs from the subject with H9 cells and
subsequent measurement of HIV-1 titers using an ELISA assay for p24
antigen levels (Popovic, M., et al., 1984, Science 204:309-321).
Another indicator of plasma HIV-1 levels and AIDS progression is
the production of inflammatory cytokines such as IL-6, IL-8 and
TNF-.alpha.; thus, efficacy of the Therapeutic can be assessed by
ELISA tests for reduction of serum levels of any or all of these
cytokines. Administration of the Therapeutic can also be evaluated
by assessing changes in CD4.sup.+ T cell levels, body weight, or
any other physical condition associated with HIV infection or AIDS
or AIDS Related Complex (ARC). Reduction in HIV viral load or
production, increase in CD4.sup.+ T cell or amelioration of
HIV-associated symptoms demonstrates utility of a Therapeutic for
administration in treatment/prevention of HIV infection.
5.6 Therapeutic Compositions and Methods of Administration
[0136] The invention provides methods of treatment and prevention
by administration to a subject in need of such treatment of a
therapeutically or prophylactically effective amount of a
Therapeutic of the invention. The subject is preferably an animal,
including, but not limited to, animals such as primates, monkeys,
cows, pigs, horses, chickens, cats, dogs, etc., and is preferably a
mammal, and most preferably human. In a specific embodiment, the
subject is a human afflicted with HIV infection or related
disorders. In a preferred embodiment, the Therapeutic is purified
(i.e., separated from components with which it is associated in its
natural environment).
[0137] Various delivery systems are known and can be used to
administer a Therapeutic of the invention, e.g., encapsulation in
liposomes, microparticles, microcapsules, recombinant cells capable
of expressing the Therapeutic, receptor-mediated endocytosis (see,
e.g., Wu and Wu, 1987, J. Biol. Chem. 262:4429-4432), construction
of a Therapeutic nucleic acid as part of a retroviral or other
vector, etc. Methods of introduction include but are not limited to
intradermal, intramuscular, intraperitoneal, intravenous,
subcutaneous, intranasal, epidural, and oral routes. The compounds
may be administered by any convenient route, for example by
infusion or bolus injection, by absorption through epithelial or
mucocutaneous linings (e.g., oral mucosa, rectal and intestinal
mucosa, etc.) and may be administered together with other
biologically active agents. Administration can be systemic or
local. In addition, it may be desirable to introduce the
pharmaceutical compositions of the invention into the central
nervous system by any suitable route, including intraventricular
and intrathecal injection; intraventricular injection may be
facilitated by an intraventricular catheter, for example, attached
to a reservoir, such as an Ommaya reservoir. Pulmonary
administration can also be employed, e.g., by use of an inhaler or
nebulizer, and formulation with an aerosolizing agent.
[0138] In a specific embodiment, it may be desirable to administer
the pharmaceutical compositions of the invention locally to the
area in need of treatment; this may be achieved, for example and
not by way of limitation, by topical application, by injection, by
means of a catheter, by means of a suppository, or by means of an
implant, said implant being of a porous, non-porous, or gelatinous
material, including membranes, such as sialastic membranes, or
fibers.
[0139] In another embodiment, the Therapeutic can be delivered in a
vesicle, in particular a liposome (see Langer, Science
249:1527-1533 (1990); Treat et al., in Liposomes in the Therapy of
Infectious Disease and Cancer, Lopez-Berestein and Fidler (eds.),
Liss, New York, pp. 353-365 (1989); Lopez-Berestein, ibid., pp.
317-327; see generally ibid.)
[0140] In yet another embodiment, the Therapeutic can be delivered
in a controlled release system. In one embodiment, a pump may be
used (see Langer, supra; Sefton, CRC Crit. Ref. Biomed. Eng. 14:201
(1987); Buchwald et al., Surgery 88:507 (1980); Saudek et al., N.
Engl. J. Med. 321:574 (1989)). In another embodiment, polymeric
materials can be used (see Medical Applications of Controlled
Release, Langer and Wise (eds.), CRC Pres., Boca Raton, Fla.
(1974); Controlled Drug Bioavailability, Drug Product Design and
Performance, Smolen and Ball (eds.), Wiley, New York (1984); Ranger
and Peppas, J. Macromol. Sci. Rev. Macromol. Chem. 23:61 (1983);
see also Levy et al., Science 228:190 (1985); During et al., Ann.
Neurol. 25:351 (1989); Howard et al., J. Neurosurg. 71:105 (1989)).
In yet another embodiment, a controlled release system can be
placed in proximity of the therapeutic target, thus requiring only
a fraction of the systemic dose (see, e.g., Goodson, in Medical
Applications of Controlled Release, supra, vol. 2, pp. 115-138
(1984)).
[0141] Other controlled release systems are discussed in the review
by Langer (Science 249:1527-1533 (1990)).
[0142] The present invention also provides pharmaceutical
compositions. Such compositions comprise a therapeutically
effective amount of a Therapeutic, and a pharmaceutically
acceptable carrier. As used herein, the term "pharmaceutically
acceptable carrier" refers to a carrier medium that does not
interfere with the effectiveness of the biological activity of the
active ingredient, is chemically inert and is not toxic to the
patient to whom it is administered. In a specific embodiment, the
term "pharmaceutically acceptable" means approved by a regulatory
agency of the Federal or a state government or listed in the U.S.
Pharmacopeia or other generally recognized pharmacopeia for use in
animals, and more particularly in humans. The term "carrier" refers
to a diluent, adjuvant, excipient, or vehicle with which the
Therapeutic is administered. Such pharmaceutical carriers can be
sterile liquids, such as water and oils, including those of
petroleum, animal, vegetable or synthetic origin, such as peanut
oil, soybean oil, mineral oil, sesame oil and the like. Water is a
preferred carrier when the pharmaceutical composition is
administered intravenously. Saline solutions and aqueous dextrose
and glycerol solutions can also be employed as liquid carriers,
particularly for injectable solutions. Suitable pharmaceutical
excipients include starch, glucose, lactose, sucrose, gelatin,
malt, rice, flour, chalk, silica gel, sodium stearate, glycerol
monostearate, talc, sodium chloride, dried skim milk, glycerol,
propylene glycol, water, ethanol and the like. The composition, if
desired, can also contain minor amounts of wetting or emulsifying
agents, or pH buffering agents. These compositions can take the
form of solutions, suspensions, emulsion, tablets, pills, capsules,
powders, sustained-release formulations and the like. The
composition can be formulated as a suppository, with traditional
binders and carriers such as triglycerides. Oral formulation can
include standard carriers such as pharmaceutical grades of
mannitol, lactose, starch, magnesium stearate, sodium saccharine,
cellulose, magnesium carbonate, etc. Examples of suitable
pharmaceutical carriers are described in "Remington's
Pharmaceutical Sciences" by E. W. Martin. Such compositions will
contain a therapeutically effective amount of the Therapeutic,
preferably in purified form, together with a suitable amount of
carrier so as to provide the form for proper administration to the
patient. The formulation should suit the mode of
administration.
[0143] In a preferred embodiment, the composition is formulated in
accordance with routine procedures as a pharmaceutical composition
adapted for intravenous administration to human beings. Typically,
compositions for intravenous administration are solutions in
sterile isotonic aqueous buffer. Where necessary, the composition
may also include a solubilizing agent and a local anesthetic such
as lignocaine to ease pain at the site of the injection. Generally,
the ingredients are supplied either separately or mixed together in
unit dosage form, for example, as a dry lyophilized powder or water
free concentrate in a hermetically sealed container such as an
ampoule or sachette indicating the quantity of active agent. Where
the composition is to be administered by infusion, it can be
dispensed with an infusion bottle containing sterile pharmaceutical
grade water or saline. Where the composition is administered by
injection, an ampoule of sterile water for injection or saline can
be provided so that the ingredients may be mixed prior to
administration.
[0144] The Therapeutics of the invention can be formulated as
neutral or salt forms. Pharmaceutically acceptable salts include
those formed with free amino groups such as those derived from
hydrochloric, phosphoric, acetic, oxalic, tartaric acids, etc., and
those formed with free carboxyl groups such as those derived from
sodium, potassium, ammonium, calcium, ferric hydroxides,
isopropylamine, triethylamine, 2-ethylamino ethanol, histidine,
procaine, etc.
[0145] The amount of the Therapeutic of the invention which will be
effective in the treatment of a particular disorder or condition
will depend on the nature of the disorder or condition, and can be
determined by standard clinical techniques. In addition, in vivo
and/or in vitro assays may optionally be employed to help predict
optimal dosage ranges. The precise dose to be employed in the
formulation will also depend on the route of administration, and
the seriousness of the disease or disorder, and should be decided
according to the judgment of the practitioner and each patient's
circumstances. Predicted suitable doses of a non-pyrogenic
preparation of LPS or lipid A or derivatives or analogs thereof for
treatment or prevention of HIV infection include, but are not
limited to, 1 ng/kg to 2 mg/kg per week. Routes of administration
of a Therapeutic include, but are not limited to, intramuscularly,
subcutaneously or intravenously. Effective doses may be
extrapolated from dose-response curves derived from in vitro or
animal model test systems.
[0146] Suppositories generally contain active ingredient in the
range of 0.5% to 10% by weight; oral formulations preferably
contain 10% to 95% active ingredient.
[0147] The invention also provides a pharmaceutical pack or kit
comprising one or more containers filled with one or more of the
ingredients of the pharmaceutical compositions of the invention.
Optionally associated with such container(s) can be a notice in the
form prescribed by a governmental agency regulating the
manufacture, use or sale of pharmaceuticals or biological products,
which notice reflects approval by the agency of manufacture, use or
sale for human administration.
6. EXAMPLE
Non-Pyrogenic LPS Stimulates .beta. Chemokine Secretion in PBMC
[0148] These experiments were carried out to demonstrate the
ability of non-pyrogenic LPS antagonists to competitively inhibit
the interaction between LPS and the cellular receptor for LPS.
Recent biochemical evidence suggests that the htrB and msbB genes
serve as lauroyl and myristoyl transferases, respectively
(Rietschel et al., 1994 FASEB J. 8:217-225; Summerville et al.,
1996, J. Clin. Invest. 97: 359-365; Lee et al., 1995, J. Biol.
Chem. 270:27151-27159). In support, mass spectrometry analysis of
LPS from an E. coli msbB mutant showed that this mutant produced a
pentaacyl lipid A that lacked the ester-linked myristoyl side chain
(Lee et al., supra). Similarly, an htrB mutant of Haemophilus
influenzae produced a mixture of pentaacyl and tetraacyl lipid A.
Thus, HtrB and MsbB transferase activities are believed to be
necessary for the generation of LPS from KDO.sub.2-lipid IV.sub.A
(Summerville et al., supra). These experiments tested whether an E.
coli htrB msbB double mutant would accumulate LPS that contained
lipid A partial structures and that would serve as a convenient
source of LPS antagonist.
6.1 Materials and Methods
[0149] Cell Culture
[0150] Strains W3110 and MLK986 were cultured on solid media both
at 30.degree. C., 37.degree. C. or 42.degree. C. prior to seeding
the liquid media. Liquid cultures (1L) were seeded the following
day at a starting inoculum of ca. 1.times.10.sup.4 cfu/ml and grown
for 16 hr at 30.degree. C., 37.degree. C. or 42.degree. C. with
shaking (250 opm).
[0151] Isolation of LPS
[0152] The liquid cultures were harvested by centrifugation at
7000.times.g for 10 min, washed once in 250 ml endotoxin-free
irrigation saline (Baxter) and the weight of the bacterial pellets
was determined. The pellets then were resuspended in endotoxin-free
water (Baxter) at a final density of 2% w/v 0.25%. Subsequently,
LPS was isolated by two cycles of hot-water phenol extraction. In
short, the bacterial suspensions were heated to 70.degree. C. to
which an equal volume of pre-warmed phenol was added and mixed for
15 min at 70.degree. C. The mixtures were cooled to 25.degree. C.
and then centrifuged at 18,000.times.g for 15 min. Following this
centrifugation the aqueous phases were removed, placed into
dialysis tubing (SpectraPor) and dialyzed against running distilled
H.sub.2O overnight. The retentates were then placed into fresh 50
ml polypropylene tubes and treated with RNaseA (100 .mu.g/ml) at
37.degree. C. for 1 hr, followed by DNaseI (50 .mu.g/ml and 5 mM
MgCl.sub.2) at 37.degree. C. for 1 hr, followed by Pronase (250
.mu.g/ml) at 37.degree. C. for 1 hr. Then EDTA was added to a final
concentration of 5 mM and the hot-water phenol extraction procedure
described above was repeated. Following dialysis the retentates
were centrifuged at 20,000.times.g for 15 min at 4.degree. C. The
supernatants were transferred to fresh Beckman 50Ti tubes and the
LPS was pelleted by centrifugation at 110,000.times.g for 2H at
4.degree. C. The supernatants were discarded and the pellets were
vacuum dried. Each LPS preparation was evaluated for DNA and
protein contamination by SDS-PAGE and silver stain, BCA protein
estimate assay and UV spectrophotometry.
[0153] PRMC Activation Assays
[0154] PBMCs were obtained from 50 ml of whole blood as described
above and resuspended in complete medium (CM; RPMI containing
pyruvate, glutamine, PenStrep, and 10% endotoxin-free human AB
serum (Life Technologies) at a density of 6.times.10.sup.6
PBMCs/ml. CM containing W3110 LPS, MLK986 LPS or synthetic lipid
IV.sub.A was placed into duplicate wells of a 96-well flat bottom
culture late (Costar) at double the target final concentration. An
equal volume of CM containing the PBMCs then was added to these
wells and the culture plates were incubated at 37.degree. C. in 5%
CO.sub.2 for 8 hr. The supernatants were then removed and stored at
70 C. Quantitation of TNF.alpha., IL-1.beta., IL-6, MIP-1.alpha.
and MIP-1.beta. in these culture supernatants was achieved by
capture ELISA (R&D Systems).
6.2 Results
[0155] LPS was extracted from Escherichia coli strain W3110 and a
htrB1::Tn10, msbB::.OMEGA.cam double mutant derivative of W3110,
strain MLK986 (Karrow et al., 1992, J. Bacteriol 174:702-710) after
culturing them at 30.degree. C., 37.degree. C. or 42.degree. C. as
described (Westphal et al., 1965, Met. Carbohyd. Res. 5:83-91). To
characterize the proinflammatory activity of LPS harvested from
W3110 and MLK986 bacilli cultured at over this temperature range,
we measured the level of TNF.alpha. in culture supernatants 8 hr
after stimulation of human PBMCs. The results showed that
significant levels of TNF.alpha. secretion was induced by parent
strain W3110 LPS at concentrations above 1 ng/ml, irrespective of
culture temperature (FIG. 1). In contrast, LPS from mutant strain
MLK986 cultured at 30.degree. C. only modestly elicited TNF.alpha.
secretion and LPS derived from MLK986 bacilli cultured at
37.degree. C. and 42.degree. C. even at concentrations as high as 1
.mu.g/ml did not elicit significant TNF.alpha. secretion in the
human PBMC activation assay (FIG. 1). This observation was
reproduced using four unrelated PBMC donors and two separate LPS
preparations. In addition, a similar secretion pattern was seen for
IL-1.beta. in the culture supernatants of PBMCs after stimulation
with each of the MLK986 and W3110 LPS preparations (Table 1).
Secretion of IL-6 was more variable from PBMC donor to PBMC donor.
In some instances LPS from MLK986 cultured either at 37.degree. C.
or 42.degree. C. induced a modest increase in IL-6 (Table 1).
However, the levels were similar to the level of IL-6 induced by
non-pyrogenic synthetic lipid IV.sub.A (ICN) and were 5-fold lower
than the level of IL-6 induced by 100-fold less W3110 LPS (Table
1). We believe these data indicate that LPS isolated from MLK986
cultured at or above 37.degree. C. possesses negligible
proinflammatory activity.
2TABLE 1 Levels of IL-1.beta. and IL-6 in human PBMC culture
supernatants after stimulation with LPS LPS source IL-1.beta. IL-6
(Culture Temperature) (pg/ml) (pg/ml) None 12 .+-. 1 2296 .+-. 43
W3110 (37.degree. C.) 7032 .+-. 366 30,698 .+-. 120 (10 ng/ml)
MLK986 (30.degree. C.) 1918 .+-. 182 16,000 .+-. 26 (1 .mu.g/ml)
MLK986 (37.degree. C.) 12 .+-. 3 7593 .+-. 221 (1 .mu.g/ml) MLK986
(42.degree. C.) 11 .+-. 4 5164 .+-. 144 (1 .mu.g/ml) Lipid IV.sub.A
(42.degree. C.) 13 .+-. 1 7581 .+-. 20 (1 .mu.g/ml)
[0156] To investigate whether MLK986 LPS possesses LPS antagonist
activity, MLK986 LPS (cultured at 37.degree. C.) at 1 .mu.g/ml was
mixed with varying amounts of W3110 LPS (also cultured at
37.quadrature.C) from 1 ng/ml to 100 ng/ml and these mixtures were
used to stimulate human PBMCs as outlined above. W3110 LPS (also
cultured at 37 C) from 1 ng/ml to 100 ng/ml alone and W3110 LPS (10
ng/ml) mixed with synthetic lipid IV.sub.A (1 .mu.g/ml) were used
as controls. The level of TNF.alpha. in culture supernatants
collected 8 hr after stimulation shows that W3110 LPS at a
concentration of 1 ng/ml and above elicited TNF.alpha. secretion
but that MLK986 LPS significantly antagonized this response (Table
2). Interestingly, LPS from MLK986 cultured at 42 C produced did
not display LPS antagonist activity. Since culture temperature has
been shown to influence LPS aggregation and influence LPS activity
(Shnyra et al., 1993, Infection and Immunity 61:5351-5360), this
later finding may be due to differential aggregation properties of
MLK986 LPS produced under the distinct culture conditions.
3TABLE 2 LPS antagonist properties of MLK986 LPS TNF.alpha.
Treatment (pg/ml) W3110 (100 ng/ml) 1404 .+-. 40 W3110 (10 ng/ml)
1192 .+-. 37 W3110 (1 ng/ml) 536 .+-. 178 MLK986/37.degree. C. (1
.mu.g/ml) <30 MLK986/37.degree. C. (1 .mu.g/ml) + W3110 <30
(100 ng/ml) MLK986/37.degree. C. (1 .mu.g/ml) + W3110 <30 (10
ng/ml) MLK986/37.degree. C. (1 .mu.g/ml) + W3110 <30 (1 ng/ml)
Lipid IV.sub.A (1 .mu.g/ml) + W3110 <30 (10 ng/ml)
[0157] In light of the growing importance of .beta. chemokines in
microbial infection (Murphy, 1994, Ann. Rev. Immunol. 12:593-633;
Cocchi et al., 1955, Science 270:1811-1815), we investigated
whether LPS from MLK986 or RsDPLA were capable of eliciting
MIP-1.alpha., MIP-1.beta. or RANTES secretion from human PBMCs in
vitro. Human PBMCs were stimulated with various doses MLK986 LPS or
RsDPLA (Kitchens et al. 1992, J. Exp. Med. 176: 485-494) and the
levels of MIP-1.alpha., MIP-1.beta. or RANTES in the culture
supernatants 8, 16, 24, and 48 hr after stimulation were determined
by quantitative capture ELISA (R&D Systems). Reproducibly, we
found that LPS from MLK986, cultured at either 37.degree. C. or
42.degree. C., and RsDPLA stimulated the secretion of MIP-1.alpha.
and MIP-1.beta. in a dose-dependent manner (FIG. 2); the peak
production of these chemokines occurred 24 hr after stimulation
(FIG. 3).
6.3 Discussion
[0158] In this example, we presented the novel finding that LPS
antagonists, both E. coli mutant LPS and R. sphaeroides
diphosphoryl lipid A (RsDPLA), possess subtle biological activity
in a human PBMC activation assay. The ability of these LPS
antagonists to elicit MIP-1.alpha. and MIP-1.beta. is inconsistent
with a passive competitive inhibition model and therefore suggests
a more complicated mechanism. Irrespective of the basis for this
response, the observation that .beta. chemokines MIP-1.alpha. and
MIP-1.beta. secretion can be elevated in the absence of endogenous
pyrogenic cytokines such as TNF.alpha. and IL-1.beta. can open new
avenues for novel therapeutic strategies that exploit this host
response.
7. EXAMPLE
Inhibition of HIV-1 Replication in Human PBMC-Derived Monocytes by
Non-Pyrogenic LPS
[0159] The following studies were conducted to demonstrate that
non-pyrogenic LPS isolated from E. coli htrB1::Tn10,
msbB::.OMEGA.cam double mutant MLK986 is capable of inhibiting HIV
replication in human cells.
[0160] 7.1 Method
[0161] Isolation of PBMCs and monocyte-derived macrophages. PBMC
healthy donors were placed in 24 well plates at 3.times.10.sup.6
cells/ml in 1 ml of growth medium (GM) (RPMI-1640+10% FBS+10% human
serum+Penn/Strep). Monocytes which had been isolated by negative
selection with magnetic beads to remove T and B cells, were place
in a 25 cm.sup.2 flask and further purified by adherence to the
flask. After washing, the monocytes were cultured in GM as
above.
[0162] 7.2 Results
[0163] Induction of .beta. chemokines. These cultures were then
treated with the LPS preparations as indicated. After 24 hours the
supernatants were collected from each these cultures and the level
of .beta.-chemokines and TNF-.alpha. and IL-1.beta. were measured
by ELISA (R&D Systems). The data shown in Table 3 are
representative of 3 different experiments, and indicate that both
MLK986-LPS and wild type LPS induce comparable levels of
.beta.-chemokines in macrophages and PBMC cultures. However, in
contrast to wild type LPS, MLK986 LPS did not induce a measurable
TNF-.alpha. response.
[0164] Inhibition of HIV-1 infection. Monocyte-derived macrophages
were treated with the LPS preparations (1 .mu.g/ml) and then
infected with HIV-1.sub.Ba-L at 0.5 ng/ml for 3 hours, washed with
PBS 4 times, and cultured in growth medium for 10 days.
Supernatants were collected at days 4, 7, and 10 days
post-infection, and tested for the presence of p24 antigen by ELISA
(Coulter). Representative data from 3 different experiments (Table
4) show that both MLK986 and wild type LPS potently inhibit HIV-1
replication in monocyte-derived macrophages. In addition,
pretreatment of human PBMCs with supernatants collected 24 hr after
stimulation of PBMC with various LPS preparations inhibited HIV-1
infection (Table 5). The data shown in FIG. 4A are representative
of 4 different experiments and demonstrate that MLK986/37 inhibits
HIV-1 chemokines. Thus, MLK986/37 induced HIV-1 inhibition in MDM
is reversed by addition of a mixture of neutralizing antibodies
against RANTES, MIP-1.alpha., and MIP-1.beta. (from R&D Systems
Inc.; 200 ug/ml each) (FIG. 4B). Further, HIV-1 replication
inhibition occurred without inducing pyrogenic cytokines (FIG. 4C).
These results clearly demonstrate that the LPS antagonist MLK986/37
potently inhibits HIV-1 replication.
4TABLE 3 Levels of .beta.-chemokines and TNF-.alpha. in PBMC
culture supernatants after 24 hours of LPS stimulation (1 mg/ml).
LPS source RANTES ng/ml MIP-1.alpha. ng/ml MIP-1.beta. ng/ml
TNF-.alpha. ng/ml none 0.212 +/- .030 0.170 +/- .008 0.416 +/- .052
<30 LPS wt 2.65 +/- 1.98 9.22 +/- 1.38 6.76 +/- .580 1.96 +/-
.969 MLK986 2.489 +/- 1.93` 8.84 +/- .830 6.72 +/- .587 <30
(Prep. P)
[0165]
5TABLE 4 HIV-1 p24 expression in macrophages pretreated with LPS.
LPS source Day 4 Day 7 Day 10 none .340 +/- .095 .890 +/- .153 1.64
+/- .562 LPS wt .018 +/- .006 27 +/- .0014 .035 +/- .005 MLK986
(Prep. .027 +/- .012 .051 +/- .025 .01 +/- .032 02)
[0166]
6TABLE 5 HIV-1 p24 expression in PBMC pretreated with supernatants
from PBMC stimulated with MLK986, wild type LPS (E. coli, SIGMA)
(both at 1 mg/ml) or control. LPS source Day 4 Day 7 none .889 +/-
.068 2.03 +/- .158 LPS wt .039 +/- .032 .081 +/- .033 MLK986 .094
+/- .067 .134 +/- .038
8. EXAMPLES
Synthetic Lipid IV.sub.A Suppresses HIV Replication without
Inducing Measurable Levels of .beta. Chemokines
[0167] The following studies were conducted to demonstrate that
non-pyrogenic LPS antagonist lipid IV.sub.A is capable of
inhibiting HIV replication in human cells.
[0168] 8.1 Methods and Results
[0169] To investigate the utility of the aforementioned findings,
we investigated whether commercially available synthetic lipid
IV.sub.A (ICN Inc.) suppressed the replication of HIV-1.sub.BAL in
human PBMC-derived monocytes. Therefore, PBMCs were obtained as
outlined in Section 6, see above, and placed into 12 well culture
flat-bottom plate and incubated in CM (see example 1) for 12 days
at 37.degree. C. in 5% CO.sub.2. Non-adherent cells were removed
and the cells were given fresh media every 2 days. After 6 days,
the adherent PBMCs were treated with synthetic lipid IV.sub.A at
1000 ng/ml, 100 ng/ml and 10 ng/ml for 24 hours. The treated cells
were subsequently infected with 0.200 ng of HIV-1.sub.BAL (Cocchi
et al., supra) for 2 hours, washed twice and incubated for a
further 19 days. Culture supernatants were then collected and the
level of p24 in these supernatants was measured by ELISA (R&D
Systems). The results of this assay show that lipid IV.sub.A
suppresses the replication of HIV-1.sub.BAL in a dose-dependent
manner (FIG. 5). These results provide clear evidence that
synthetic LPS antagonists, such as lipid IV.sub.A, are capable of
suppressing HIV replication over a wide range of
concentrations.
9. EXAMPLES
Non-Pyrogenic LPS Suppresses HIV Replication Without Displaying LPS
Antagonist Activity
[0170] The following studies were conducted to demonstrate that
non-pyrogenic LPS isolated from E. coli htrB1::Tn10,
msbB::.OMEGA.cam double mutant MLK986 cultured at 42.degree. C. is
capable of inhibiting HIV replication in human cells.
[0171] 9.1 Methods and Results
[0172] We investigated whether LPS isolated from MLK986 cultured at
42.degree. C. (MLK986/42) suppressed the replication of
HIV-1.sub.BAL in human PBMC-derived monocytes. This LPS preparation
induces lower levels of .beta. chemokines that LPS isolated from
MLK986 cultured at 37.degree. C. and did not display LPS antagonist
activity (see above). PBMC-derived monocytes were obtained as
outlined in Section 8, see above. After 6 days, the PBMC-derived
monocytes were treated with MLK986/42 at 1000 ng/ml, 100 ng/ml and
10 ng/ml for 24 hours. The treated cells were subsequently infected
with 0.200 ng of HIV-1.sub.BAL (Cocchi et al., supra) for 2 hours,
washed twice and incubated for a further 19 days. Culture
supernatants were then collected and the level of p24 in these
supernatants was measured by ELISA (R&D Systems). The results
of this assay show that MLK986/42 suppresses the replication of
HIV-1.sub.BAL in a dose-dependent manner.
[0173] This example provides direct evidence that non-pyrogenic LPS
preparations that lack LPS antagonist properties, such as
MLK986/42, are capable of suppressing HIV replication over a wide
range of concentrations.
[0174] The present invention is not to be limited in scope by the
specific embodiments described herein. Indeed, various
modifications of the invention in addition to those described
herein will become apparent to those skilled in the art from the
foregoing description and accompanying figures. Such modifications
are intended to fall within the scope of the appended claims.
[0175] Various references are cited herein, the disclosures of
which are incorporated by reference in their entireties.
* * * * *