U.S. patent application number 10/353917 was filed with the patent office on 2003-11-13 for immunomodulatory polynucleotides in treatment of an infection by an intracellular pathogen.
Invention is credited to Carson, Dennis, Catanzaro, Antonino, Hayashi, Tomoko, Kornbluth, Richard, Raz, Eyal.
Application Number | 20030212028 10/353917 |
Document ID | / |
Family ID | 22656229 |
Filed Date | 2003-11-13 |
United States Patent
Application |
20030212028 |
Kind Code |
A1 |
Raz, Eyal ; et al. |
November 13, 2003 |
Immunomodulatory polynucleotides in treatment of an infection by an
intracellular pathogen
Abstract
The present invention features methods for treatment or
prevention of infection by intracellular pathogens (e.g.,
Mycobacterium species) by administration of an immunomodulatory
nucleic acid molecule. In one embodiment, immunomodulatory nucleic
acid molecule are administered in combination with another
anti-pathogenic agent to provide a synergistic anti-pathogenic
effect.
Inventors: |
Raz, Eyal; (Del Mar, CA)
; Kornbluth, Richard; (La Jolla, CA) ; Catanzaro,
Antonino; (San Diego, CA) ; Hayashi, Tomoko;
(San Diego, CA) ; Carson, Dennis; (Del Mar,
CA) |
Correspondence
Address: |
BOZICEVIC, FIELD & FRANCIS LLP
200 MIDDLEFIELD RD
SUITE 200
MENLO PARK
CA
94025
US
|
Family ID: |
22656229 |
Appl. No.: |
10/353917 |
Filed: |
January 28, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10353917 |
Jan 28, 2003 |
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09774403 |
Jan 30, 2001 |
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6552006 |
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60179353 |
Jan 31, 2000 |
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Current U.S.
Class: |
514/44R |
Current CPC
Class: |
A61K 31/00 20130101;
A61K 2300/00 20130101; A61K 31/7024 20130101; A61P 37/06 20180101;
A61K 31/711 20130101; A61K 31/711 20130101; A61K 45/06 20130101;
A61K 31/00 20130101; A61K 31/711 20130101 |
Class at
Publication: |
514/44 |
International
Class: |
A61K 048/00 |
Goverment Interests
[0002] This invention was made, at least in part, with a government
grant from the National Institutes of Health (NIH Grant Nos.
A140682, A147078, and HL57911). Thus, the U.S. government may have
certain rights in this invention.
Claims
That which is claimed is:
1. A method for treating an intracellular pathogen infection in a
subject, the method comprising: administering to a subject an
immunomodulatory nucleic acid molecule in an amount effective to
inhibit intracellular replication of the intracellular pathogen;
and administering to the subject an anti-pathogenic agent in an
amount effective to decrease or inhibit growth of the intracellular
pathogen, thereby treating the pathogen.
2. The method of claim 1, wherein the immunomodulatory nucleic acid
molecule is selected from the group consisting of an
immunostimulatory oligodeoxyribonucleotide (ISS-ODN); an isolated,
detoxified bacterial polynucleotide; and an ISS-enriched plasmid
DNA.
3. The method of claim 1, wherein the immunomodulatory nucleic acid
molecule comprises a CpG motif selected from the group consisting
of: a) 5'-Purine-Purine-[C]-[G]-Pyrimidine-Pyrimidine-3'; b)
5'-Purine-TCG-Pyrimidine-Pyrimidine-3'; c) 5'-[TCG].sub.n-3', where
n is any integer that is 1 or greater; and d)
5'-Purine-Purine-CG-Pyrimidine-P- yrimidine-CG-3'. e)
5'-Purine-TCG-Pyrimidine-Pyrimidine-CG-3'
4. The method of claim 1, wherein the immunomodulatory nucleic acid
molecule comprises a sequence selected from the group consisting
of: AACGCC, AACGCT, AACGTC, AACGTT, AGCGCC, AGCGCT, AGCGTC, AGCGTT,
GACGCC, GACGCT, GACGTC, GACGTT, GGCGCC, GGCGCT, GGCGTC, GGCGTT,
ATCGCC, ATCGCT, ATCGTC,
ATCGTT,GTCGCC,GTCGCT,GTCGTC,GTCGTT,TCGTCG,TCGTCGTCG,
AACGCCCG,AACGCTCG,AACGTCCG,AACGTTCG,AGC.GCCCG,AGCGCTCG,
AGCGTCCG,AGCGTTCG,GACGCCCG,GACGCTCG,GACGTCCG,GACGTTCG,
GGCGCCCG,GGCGCTCG,GGCGTCCG,GGCGTTCG, ATCGCCCG,ATCGCTCG,
ATCGTCCG,ATCGTTCG, GTCGCCCG, GTCGCTCG, GTCGTCCG, and GTCGTTCG.
5. The method of claim 4, wherein the immunomodulatory nucleic acid
molecule comprises the sequence AACGTTCG.
6. The method of claim 1, wherein the immunomodulatory nucleic acid
molecule is administered in an amount effective to provide
synergistic anti-pathogenic activity with the anti-pathogenic
agent.
7. The method of claim 1, wherein the immunomodulatory nucleic acid
molecule and the anti-pathogenic agent are administered
concurrently.
8. The method of claim 1, wherein the intracellular pathogen is a
bacterium.
9. The method of claim 8, wherein the bacterium is a Mycobacterium
bacterium.
10. The method of claim 9, wherein the bacterium is selected from
the group consisting of Mycobacterium tuberculosis and
Mycobacterium avium.
11. The method of claim 1, wherein said administering enhances
indoleamine 2,3-dioxygenase activity in the subject.
12. The method of claim 1, wherein the subject is
immunocompromised.
13. The method of claim 12, wherein the immunocompromised subject
has a reduced number of CD4+ T cells relative to an immunocompetent
subject.
14. A method for treating a mycobacterial infection in a subject,
the method comprising: administering to a subject an
immunomodulatory nucleic acid molecule in an amount effective to
inhibit replication of a Mycobacterium bacterium, thereby treating
mycobacterial indection in the subject.
15. The method of claim 14, wherein the immunomodulatory nucleic
acid molecule is selected from the group consisting of an
immunostimulatory oligodeoxyribonucleotide (ISS-ODN); an isolated,
detoxified bacterial polynucleotide; and an ISS-enriched plasmid
DNA.
16. The method of claim 14, wherein the immunomodulatory nucleic
acid molecule comprises a CpG motif selected from the group
consisting of: a)
5'-Purine-Purine-[C]-[G]-Pyrimidine-Pyrimidine-3'; b)
5'-Purine-TCG-Pyrimidine-Pyrimidine-3'; c) 5'-[TCG].sub.n-3', where
n is any integer that is 1 or greater; and d)
5'-Purine-Purine-CG-Pyrimidine-P- yrimidine-CG-3'. e)
5'-Purine-TCG-Pyrimidine-Pyrimidine-CG-3'
17. The method of claim 14, wherein the immunomodulatory nucleic
acid molecule comprises a sequence selected from the group
consisting of: AACGCC, AACGCT, AACGTC, AACGTT, AGCGCC, AGCGCT,
AGCGTC, AGCGTT, GACGCC, GACGCT, GACGTC, GACGTT, GGCGCC, GGCGCT,
GGCGTC, GGCGTT, ATCGCC, ATCGCT, ATCGTC, ATCGTT, GTCGCC, GTCGCT,
GTCGTC, GTCGTT, TCGTCG, TCGTCGTCG, AACGCCCG, AACGCTCG, AACGTCCG,
AACGTTCG, AGCGCCCG, AGCGCTCG, AGCGTCCG, AGCGTTCG, GACGCCCG,
GACGCTCG, GACGTCCG, GACGTTCG, GGCGCCCG, GGCGCTCG, GGCGTCCG,
GGCGTTCG, ATCGCCCG, ATCGCTCG, ATCGTCCG, ATCGTTCG, GTCGCCCG,
GTCGCTCG, GTCGTCCG, and GTCGTTCG.
18. The method of claim 17, wherein the immunomodulatory nucleic
acid molecule comprises the sequence AACGTTCG.
19. The method of claim 14, wherein said administering results in
induction of an immune response effective against infection by a
mycobacterial pathogen.
20. The method of claim 14, wherein the immunomodulatory nucleic
acid molecule is administered with an anti-pathogenic agent.
21. The method of claim 20, wherein the immunomodulatory nucleic
acid molecule is administered in an amount effective to provide
synergistic anti-pathogenic activity with the anti-pathogenic
agent.
22. The method of claim 20, wherein the immunomodulatory nucleic
acid molecule and the anti-pathogenic agent are administered
concurrently.
23. The method of claim 14, wherein the bacterium is Mycobacterium
tuberculosis.
24. The method of claim 14, wherein the bacterium is Mycobacterim
avium.
25. The method of claim 14, wherein the subject is
immunocompromised.
26. The method of claim 25, wherein the immunocompromised subject
has a reduced number of CD4+ T cells relative to a immunocompetent
subject.
27. A method for inducing in a subject an immune response against a
Mycobacteriurn bacterium, the method comprising: administering to a
subject an amount of an immunomodulatory nucleic acid molecule in
an amount effective to elicit an immune response against a
Mycobacterium bacterium; wherein said administering results in
induction of an immune response effective to protect the subject
against onset of disease or to decrease severity of symptoms of
disease caused by infection by the Mycobacterium bacterium.
28. The method of claim 27, wherein the immunomodulatory nucleic
acid molecule comprises a CpG motif selected from the group
consisting of: a)
5'-Purine-Purine-[C]-[G]-Pyrimidine-Pyrimidine-3'; b)
5'-Purine-TCG-Pyrimidine-Pyrimidine-3'; c) 5'-[TCG].alpha.-3',
where n is any integer that is 1 or greater; and d)
5'-Purine-Purine-CG-Pyrimidine-P- yrimidine-CG-3'. e)
5'-Purine-TCG-Pyrimidine-Pyrimidine-CG-3'
29. The method of claim 27, wherein the immunomodulatory nucleic
acid molecule comprises a sequence selected from the group
consisting of: AACGCC, AACGCT, AACGTC, AACGTT, AGCGCC, AGCGCT,
AGCGTC, AGCGTT, GACGCC, GACGCT, GACGTC, GACGTT, GGCGCC, GGCGCT,
GGCGTC, GGCGTT, ATCGCC, ATCGCT, ATCGTC, ATCGTT, GTCGCC, GTCGCT,
GTCGTC, GTCGTT, TCGTCG, TCGTCGTCG, AACGCCCG, AACGCTCG, AACGTCCG,
AACGTTCG, AGCGCCCG, AGCGCTCG, AGCGTCCG, AGCGTTCG, GACGCCCG,
GACGCTCG, GACGTCCG, GACGTTCG, GGCGCCCG, GGCGCTCG, GGCGTCCG,
GGCGTTCG, ATCGCCCG, ATCGCTCG, ATCGTCCG, ATCGTTCG, GTCGCCCG,
GTCGCTCG, GTCGTCCG, and GTCGTTCG.
30. The method of claim 29, wherein the immunomodulatory nucleic
acid molecule comprises the sequence AACGTTCG.
31. The method of claim 27, wherein the bacterium is Mycobacterium
tuberculosis.
32. The method of claim 27, wherein the bacterium is Mycobacterium
avium.
33. The method of claim 27, wherein the subject is
immunocompromised.
34. The method of claim 33, wherein the immunocompromised subject
has a reduced number of CD4+ T cells relative to an immunocompetent
subject.
35. A method treating a mycobacterial infection, the method
comprising: administering to a subject an amount of an
immunomodulatory nucleic acid molecule in an amount effective to
inhibit intracellular replication of a Mycobacterium bacterium in
the subject; and administering to the subject an antimicrobial
agent in an amount effective to decrease or inhibit growth of the
Mycobacterium bacterium; wherein said administering is effective to
decrease severity of symptoms of disease caused by the
Mycobacterium bacterium.
36. The method of claim 35, wherein the immunomodulatory nucleic
acid molecule is administered in an amount effective to provide a
synergistic, antimicrobial effect with the antimicrobial agent.
37. The method of claim 35, wherein the immunomodulatory nucleic
acid comprises a sequence selected from the group consisting of:
AACGCC, AACGCT, AACGTC, AACGTT, AGCGCC, AGCGCT, AGCGTC, AGCGTT,
GACGCC, GACGCT, GACGTC, GACGTT, GGCGCC, GGCGCT, GGCGTC, GGCGTT,
ATCGCC, ATCGCT, ATCGTC, ATCGTT, GTCGCC, GTCGCT, GTCGTC, GTCGTT,
TCGTCG, TCGTCGTCG, AACGCCCG, AACGCTCG, AACGTCCG, AACGTTCG,
AGCGCCCG, AGCGCTCG, AGCGTCCG, AGCGTTCG, GACGCCCG, GACGCTCG,
GACGTCCG, GACGTTCG, GGCGCCCG, GGCGCTCG, GGCGTCCG, GGCGTTCG,
ATCGCCCG, ATCGCTCG, ATCGTCCG, ATCGTTCG, GTCGCCCG, GTCGCTCG,
GTCGTCCG, and GTCGTTCG.
38. The method of claim 37, wherein the immunomodulatory nucleic
acid comprises the sequence AACGTTCG.
39. The method of claim 35, wherein said administering of the
immunomodulatory nucleic acid enhances indoleamine 2,3-dioxygenase
activity in the subject.
40. A method for treating an intracellular pathogen infection in a
subject, the method comprising: administering to a subject an
immunomodulatory nucleic acid molecule in an amount effective to
enhance indoleamine 2,3-dioxygenase activity in the subject,
thereby inhibiting intracellular replication by an intracellular
pathogen and treating infection in the subject.
41. The method of claim 40, wherein the immunomodulatory nucleic
acid molecule is selected from the group consisting of an
immunostimulatory oligodeoxyribonucleotide (ISS-ODN); an isolated,
detoxified bacterial polynucleotide; and an ISS-enriched plasmid
DNA.
42. The method of claim 40, wherein the immunomodulatory nucleic
acid molecule comprises a CpG motif selected from the group
consisting of: a)
5'-Purine-Purine-[C]-[G]-Pyrimidine-Pyrimidine-3'; b)
5'-Purine-TCG-Pyrimidine-Pyrimidine-3'; c) 5'-[TCG].sub.n,-3',
where n is any integer that is 1 or greater; and d)
5'-Purine-Purine-CG-Pyrimidine-P- yrimidine-CG-3'. e)
5'-Purine-TCG-Pyrimidine-Pyrimidine-CG-3'
43. The method of claim 40, wherein the immunomodulatory nucleic
acid molecule comprises a sequence selected from the group
consisting of: AACGCC, AACGCT, AACGTC, AACGTT, AGCGCC, AGCGCT,
AGCGTC, AGCGTT, GACGCC, GACGCT, GACGTC, GACGTT, GGCGCC, GGCGCT,
GGCGTC, GGCGTT, ATCGCC, ATCGCT, ATCGTC, ATCGTT, GTCGCC, GTCGCT,
GTCGTC, GTCGTT, TCGTCG, TCGTCGTCG, AACGCCCG, AACGCTCG, AACGTCCG,
AACGTTCG, AGCGCCCG, AGCGCTCG, AGCGTCCG, AGCGTTCG, GACGCCCG,
GACGCTCG, GACGTCCG, GACGTTCG, GGCGCCCG, GGCGCTCG, GGCGTCCG,
GGCGTTCG, ATCGCCCG, ATCGCTCG, ATCGTCCG, ATCGTTCG, GTCGCCCG,
GTCGCTCG, GTCGTCCG, and GTCGTTCG.
44. The method of claim 43, wherein the immunomodulatory nucleic
acid molecule comprises the sequence AACGTTCG.
45. The method of claim 40, wherein the immunomodulatory nucleic
acid molecule is administered with an anti-pathogenic agent.
46. The method of claim 45, wherein the immunomodulatory nucleic
acid molecule is administered in an amount effective to provide
synergistic anti-pathogenic activity with the anti-pathogenic
agent.
47. The method of claim 45, wherein the immunomodulatory nucleic
acid molecule and the anti-pathogenic agent are administered
concurrently.
48. The method of claim 40, wherein the intracellular pathogen is a
Mycobacterium bacterium.
49. The method of claim 48, wherein the bacterium is selected from
the group consisting of Mycobacterium tuberculosis and
Mycobacterium avium.
50. The method of claim 40, wherein the subject is
immunocompromised.
51. The method of claim 50, wherein the immunocompromised subject
has a reduced number of CD4+ T cells relative to an immunocompetent
subject.
Description
CROSS-REFERENCE To RELATED APPLICATIONS
[0001] This application is claims the benefit of U.S. provisional
patent application No. 60/179,353, filed Jan. 31, 2000, which is
incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0003] The invention relates generally to the field of prevention
and treatment of infectious diseases, particularly infection by
intracellular pathogens such as Mycobacterium.
BACKGROUND OF THE INVENTION
[0004] The broad classification of intracellular pathogens includes
viruses, bacteria, protozoa, fungi, and intracellular parasites.
These virulent pathogens multiply within the cells of the infected
host organism rather than extracellularly and are major causes of
morbidity and fatality world-wide. For example, intracellular
pathogens are responsible for an estimated 10,000,000 new cases of
tuberculosis per year in the world (approximately 25,000 per year
in the United States), approximately 3,000,000 deaths per year from
tuberculosis, an estimated 12,000,000 cases of leprosy, and an
estimated 10,000,000 cases of American trypanosomiasis (Chagas
disease). Furthermore, intracellular pathogens also cause other
important diseases including cutaneous and visceral leishmaniasis,
listeriosis, toxoplasmosis, histoplasmosis, trachoma, psittacosis,
Q-fever, and Legionellosis including Legionnaires' disease. Few
vaccines are available against such diseases and the pathogens are
developing resistance to commonly used drugs.
[0005] One particular genus of intracellular bacteria,
Mycobacteria, is a significant cause of morbidity and mortality,
particularly among immunocompromised or elderly individuals and in
countries with limited medical resources. Ninety-five percent of
human infections are caused by seven species: Mycobacterium
tuberculosis, M. avium (also known as the mycobacterium avium
complex or M. avium-intracellulare), M. leprae, M. kansasii, M.
fortuitum, M. chelonae, and M. absecessus. The most common
mycobacterial infections in the United States are pulmonary
infections by M. tuberculosis or M. avium. Such mycobacterial
infections have been of increasing concern over the past decade,
particularly in light of the increasing incidence of multi-drug
resistant strains.
[0006] M. tuberculosis is the causative agent of tuberculosis, the
classic human mycobacterial disease. Disease is spread by close
person-to-person contact through inhalation of infectious aerosols;
infection can be established if as few as one to three bacilli
reach the alveolar spaces. Estimates indicates that one-third of
the world's population, including 10 million in the U.S., are
infected with M. tuberculosis, with 8 million new cases and 3
million deaths reported world wide each year. Although incidence of
tuberculosis steadily decreased since the early 1900s, this trend
changed in 1984 with increased immigration from endemic countries
and increased infection in the homeless, drug and alcohol abusers,
prisoners, and HIV-infected individuals ((1995) Morbid. Mortal.
Weekly Rep 44:1-87). Due to the difficulties in eradicating disease
in most of these populations, tuberculosis has again threatened to
pose a significant public health risk.
[0007] Mycobacterium avium is generally less of a health risk for
individuals with normal immune responses; M. avium can transiently
colonize these individuals, but disease due to M. avium is rare.
However, M. avium infection can cause serious disease in patients
having compromised pulmonary function (e.g., patients with chronic
bronchitis obstructive pulmonary disease, or pre-existing pulmonary
damage (e.g., due to previous pulmonary infections or other
disease). Infection in individuals having compromised pulmonary
function is clinically very similar to infection by M.
tuberculosis.
[0008] M. avium infection poses the greatest health risk to
immunocompromised individuals, and is one of the most common
opportunistic infections in patients with AIDS (Horsburgh (1991)
New Eng. J. Med. 324:1332-1338). In contrast with disease in other
patients, M. avium infection can be very serious in
immunocompromised individuals (e.g., AIDS patients, who have a low
CD4+ T-cell count (Crowe, et al. (1991) J. AIDS 4:770-776)), and
can result in disseminated infection in which virtually no organ is
spared. The magnitude of such disseminated M. avium infections is
overwhelming, with the bacterial load in some patients resulting in
tissues that are literally filled with mycobacteria and with
hundreds to thousands of bacilli per milliliter of blood. When
disseminated disease occurs, M. avium infection results in
considerable morbidity, and is a significant contributor to
mortality in AIDS patients. Although highly active anti-retroviral
therapy currently used to treat HIV-infected patients prevents the
onset of M. avium infection to some extent (Autran, et al. (1997)
Science. 277:112-116), this infection is extremely difficult to
treat when encountered because of its poor responsiveness to
anti-mycobacterial therapy (Chin, et al. (1994) J. Infect. Dis.
170:578-584; Masur (1993) New Eng. J. Med. 329:898-904).
[0009] As noted above, mycobacterial infection is normally acquired
through inhalation of aerosolized infectious particles. Following
inhalation, mycobacteria predominately infect and multiply within
macrophages (Edwards, et al. (1986) Am. Rev. Respir. Dis.
134:1062-1071). The bacteria attach to and enter macrophages with
the help of specific receptors expressed on the surface of these
cells (Bermudez, et al. (1991) Infect. Immun. 59:1697-1702; Rao, et
al. (1993) Infect. Immun. 61:663-670; Roecklein, et al. (1992) J.
Lab. Clin. Med. 119:772-781). Studies have shown that macrophages
secrete several cytokines such as tumor necrosis factor
(TNF)-.alpha., interleukin (IL)-1.beta., IL-6, granulocyte
macrophage colony stimulating factor (GM-CSF), and granulocyte
colony stimulating factor (Fattorini, et al. (1994) J. Med.
Microbiol. 40:129-133; Newman, et al. (1991) J. Immunol.
147:3942-3948) in response to infection with mycobacteria. T cell
products such as interferon (IFN)-y and IL-12 are known to be
extremely important for anti-mycobacterial activity of macrophages
(Fattorini, et al. (1994) J. Med. Microbiol. 40: 129-133) as well
as in vivo in humans and mice (Appelberg, et al. (1994) Infect.
Immun. 62:3962-3971; Holland, et al. (1994) New Eng. J. Med.
330:1348-1355; Kobayashi, et al. (1995) Antimicrob. Agents
Chemotherapy. 39:1369-1371).
[0010] Treatment of mycobacterial infections is complicated and
difficult. For example, treatment of M. tuberculosis and of M.
avium infections requires a combination of relatively toxic agents,
usually three different drugs, for at least six months. The
toxicity and intolerability of these medications usually result in
low compliance and inadequate treatment, which in turn increases
the chance of therapeutic failure and enhances the selection for
drug-resistant organisms. Treatment of mycobacterial infections is
further complicated in pregnant women, patients with pre-existing
liver or renal diseases, and immunocompromised patients, e.g., AIDS
patients.
[0011] Immunomodulatory sequences (hereinafter referred to as
"ISS") were initially discovered in the mycobacterial genome as DNA
sequences that selectively enhance NK cell activity (Yamamoto, et
al. (1992) Microbiol. Immunol. 36:983-997). Uptake of mycobacterial
DNA or ISS has been shown to activate cells of the innate immune
system, such as NK cells and macrophages and stimulating a type-i
like response (Roman, et al. (1997) Nature Med. 3:849-854).
Further, administration of ISS has been shown activate NK cells
(Krieg, A et al. (1995) Nature. 374:546-549), stimulate B cells to
proliferate and to produce IgM antibodies (Krieg, A et al. (1995)
Nature. 374:546-549; Messina, et al. (1991) J. Immunol.
147:1759-1764;), stimulate production of cytokines, such as IFNs,
IL-12; IL-18 and TNF-.alpha. (Sparwasser, et al. (1998) Eur. J.
Immunol. 28:2045-2054; Sparwasser, et al. (1997) Eur. J. Immunol.
27:1671-1679; Stacey, et al. (1999) Infect. Immun. 67:3719-3726;
Stacey, et al. (1996) J. Immunol. 157:2116-2122; Halpern, et al
(1996) Cell. Immunol. 167:72-78; Klinman, et al. (1996) Proc. Natl.
Acad. Sci. U.S.A. 93:2879-2883) and up-regulate co-stimulatory
receptors (Martin-Orozco, et al. (1999) Int. Immun. 11:1111-1118;
Sparwasser, et al. (1998) Eur. J. Immol. 28:2045-2054).
[0012] Previous studies have demonstrated the ability of
immunomodulatory nucleic acid to enhance innate immunity and host
survival against intracellular pathogens such as Listeria
monocytogenes, Leishmania major, and Francisella tularensis (Krieg,
et al. (1998) J. Immunol. 161:2428-2434; Walker, et al. (1999)
Proc. Natl. Acad. Sci. U.S.A. 96:6970-6975; Zimmermann, et al.
(1998) J. Immunol. 160:3627-3630; Klinman, et al. (1999) Infect.
Immun. 67:5658-5663). Walker, et al. found that injection of BALB/c
mice with CpG-ODN 1826 four hours after inoculation with live L.
major promastigote organisms protected 65% of animals tested from
progressive infection, suggesting that CpG-ODN can redirect the
harmful immune response elicited by live L. major parasites and
that CpG-ODN might be efficacious in the treatment of early
leishmaniasis (Walker, et al. (1999) Proc. Natl. Acad. Sci. U.S.A.
96:6970-6975). Zimmermann et al. report that single injections of
CpG-ODN protected L. major-infected BALB/c mice when given during
the first 8 days of infection but failed when given later.
Zimmermann also found that 5 of 6 L. major-infected BALB/c mice
were able to control the infection when given three consecutive
doses of CpG-ODN at 5 day intervals starting on day 15 or 20 post
infection (Zimmermann, et al. (1998) J. Immunol.
160:3627-3630).
[0013] In their studies with L. monocytogenes, Kreig, et al. found
that IFN-.gamma. production is induced rapidly by ISS
administration, returning to the basal level within 24 hours, while
IL-12 (p40 and p70) is induced immediately after infection and
lasts for at least 8 days (Krieg, et al. (1998) J. Immunol.
161:2428-2434). In the murine leishmaniasis model, the serum IL-12
level in the ISS-treated mice was found to be 10-fold higher than
L. major-infected control mice (Zimmermann, et al. (1998) J.
Immunol. 160:3627-3360).
[0014] Exogenous administration of type-1 cytokines, such as IL-12
and IFN-.gamma. increase protection against M. avium infection in
humans and mice (Appelberg, et al. (1994) Infect. Immun.
62:3962-3971; Holland, et al. (1994) New Eng. J. Med.
330:1348-1355; Kobayashi, et al. (1995) Antimicrob. Agents
Chemotherapy. 39:1369-1371). IFN-.gamma. and IL-12 are known to be
important in host anti-mycobacterial immunity (Doherty, et al.
(1997) J. Immunol. 158:4822-4831; Doherty,et al. (1998) J. Immunol.
160:5428-5435). However, administration of such cytokines is
potentially dangerous to the patient, is expensive and does not
provide an attractive means of preventing or treating existing
infections by intracellular pathogens. Furthermore, administration
of these cytokines can itself be associated with undesirable
side-effects which are due at least in part to toxicity, especially
at dosages sufficient to stimulate the subject's immune system.
[0015] DNA vaccines may provide an alternative method for therapy.
DNA vaccination with a plasmid which encodes M. avium antigens (65
kDa and antigen 85B) had a protective effect against M. avium
infection in mice (Velaz-Faircloth, et al. (1999) Infect. Immun.
67:4243-4250). Similarly, plasmid DNA which encodes antigen 85B,
ESAT-6 and MPT64 (Kamath, et al. (1999) Infect. Immun.
67:1702-1707), and hsp-65 (Bonato, et al. (1998) Infect. Immun.
66:169-175) yielded protective immunity against M. tuberculosis
infection. Further DNA vaccines based upon administration of a
polynucleotide encoding a mycobacterial antigen are described in WO
98/53075. However, while these methods appear promising, DNA
vaccination requires identification of an antigen that will induce
a protective immune response. Furthermore, the immune response
elicited by these vaccines is predominantly a type-1 response
(i.e., mediated by Th1 cells and primarily resulting in production
of antibodies). As discussed above, a robust cellular immune type-I
immune response (i.e., an immune response mediated by Th1 cells and
primarily resulting in activation of cytotoxic T cells, which
secrete IFN-.gamma.) is likely required to provide effective
immunity against such intracellular pathogens. Finally, while DNA
vaccines may provide some protection against infection in a
preventive mode, their effectiveness against an ongoing infection
is not proven.
[0016] There remains a need in the field for effective methods for
the treatment and prevention of infection by intracellular
pathogens.
SUMMARY OF THE INVENTION
[0017] The present invention features methods for treatment or
prevention of infection by intracellular pathogen by administration
of an immunomodulatory nucleic acid molecule (ISS). In one
embodiment, ISS are administered in combination with another
anti-pathogenic agent to provide a synergistic anti-pathogenic
effect. In a preferred embodiment, the intracellular pathogen is
Mycobacterium species.
[0018] A primary object of the invention is to provide an effective
method for the prevention and/or treatment of intracellular
pathogen infections in a host, particularly mycobacterial
infections.
[0019] Another object of the invention is to enhance the
anti-pathogenic activity, particularly the anti-mycobacterial
activity, of conventional chemotherapeutics to facilitate more
effective clearance of the organism from an active infection in a
subject.
[0020] One advantage of the invention is that, since
immunomodulatory nucleic acid molecules act through induction of
the immune response of the host, the use of immunomodulatory
nucleic acid molecules will not substantially result in the
selection of resistant organisms. Still another advantage is that
immunomodulatory nucleic acids acts in synergy with conventional
antibiotics, particularly in the context of treatment of
mycobacterial infection.
[0021] These and other objects and advantages will be readily
apparent to the ordinarily skilled artisan upon reading the
disclosure provided herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a graph showing the effect of immunomodulatory
nucleic acid molecules (ISS), exemplified here by immunomodulatory
DNA oligonucleotides (ISS-ODN), on intracellular growth of M. avium
in human monocyte-derived macrophages (hMDM) in vitro. Results
shown are representative of three experiments. Closed circles,
medium alone; small diamonds, mutated ISS; inverted triangle, ISS
at 3 .mu.g/ml; closed square, ISS at 10 .mu.g/ml; and closed
triangle, ISS at 30 .mu.g/ml.
[0023] FIG. 2 is a graph showing the effect of ISS upon infected
hMDM. ISS, ISS added; medium, medium alone.
[0024] FIG. 3 is a graph showing the effect of ISS and antibiotics
upon infected hMDM. ISS, ISS; CLA, clarithromycin.
[0025] FIGS. 4A-4B are graphs showing the effect of ISS,
exemplified here by ISS-ODN, on intracellular growth of M. avium in
hMDM in vitro (FIG. 4A) and effect of ISS and antibiotics upon
infected hMDM (FIG. 4B). Closed square, medium alone; closed
circle, mutated ISS; closed triangle, ISS. ISS, ISS-ODN; M-ODN,
mutated-ODN; CLA, clarithromycin. Results shown are mean.+-.SD for
three experiments. *p<0.01 compared to CFU recovered from cells
treated with M-ODN or medium alone.
[0026] FIGS. 5A-5C are graphs showing the effect of ISS and
antibiotics on mBMDM in vivo (FIG. 5A) and in vitro (FIGS. 5B-5D).
Results shown are mean.+-.SD for three experiments. *p<0.05
compared to CFU in the organs of control mice that received CLA
only or a combination of CLA and M-ODN.
[0027] FIG. 6 is a graph showing the effect of ISS, exemplified
here by ISS-ODN, on M. avium (106 organisms/mouse) growth in
C57B1/6 mice. Results shown are mean.+-.SD of the number of CFU per
organ (spleen, top panel; lung, bottom panel). ISS,closed circles;
PBS (control), triangles and dashed lines. *p<0.05 compared to
CFU in the organs of control mice that received PBS instead of ISS.
Results shown are mean.+-.SD.
[0028] FIGS. 7A-7C are graphs showing the effect of ISS,
exemplified here by ISS-ODN, on M. avium (107 organisms/mouse)
growth in C57B1/6 mice. Results shown are mean.+-.SD of the number
of CFU per organ (spleen, FIG. 7A; lung, FIG. 7B; liver, FIG. 7C).
ISS, closed circles; PBS (control), triangles and dashed lines.
*p<0.05 compared to CFU in the organs of control mice that
received PBS instead of ISS. Results shown are mean.+-.SD.
[0029] FIG. 8 is a graph showing IFN-.gamma. production in M.
avium-infected mice pre-treated with ISS, exemplified here by
ISS-ODN. Levels at weeks 2, 4, and 6 are shown in left, center, and
right panels, respectively. Uninfected, closed circles; PBS-treated
control, open circles; ISS-ODN treated, closed triangles.
[0030] FIGS. 9A-9B are graphs showing the effect of ISS on
intracellular growth of M. avium in mBMDM in vitro on days 1, 3,
and 7 after infection (FIG. 9A) and 7 days after infection (FIG.
9B). Closed square, medium alone; closed circle, mutated ISS;
closed triangle, ISS. Results shown are mean.+-.SD for triplicate
experiments. *p<0.01 compared to CFU recovered from cells
treated with M-ODN or medium alone.
[0031] FIGS. 10A-10C are graphs showing the CD4.sup.+ (FIG. 10A),
CD8.sup.+ (FIG. 10B), and IFN-.gamma..sup.+ (FIG. 10C) T cell
responses of mice treated with either ISS or M-ODN prior to
infection. Splenocytes were pooled within groups for intracellular
IFN-.gamma. assays (panels A, B). For total IFN-.gamma. produced,
results represent the mean.+-.SD (panel C).
[0032] FIGS. 11A and 11B are schematics, and FIG. 11C a graph,
showing the effect of ISS, exemplified here by ISS-ODN, on
indoleamine 2,3-dioxygenase (IDO) in mouse cells. FIG. 11A
represents results of semi-quantitative RT-PCR assessment of IDO
induction in mice 16 hours after ISS injection. -, injected with
saline; +, injected with ISS-ODN. FIG. 11B represents results of
semi-quantitative RT-PCR assessment of IDO induction in ISS-ODN
pre-treated mBMDM 4, 8, and 24 hours after infection with M. avium.
1, medium alone; 2, ISS-ODN treatment alone; 3, M. avium infection
alone; 4, ISS-ODN treatment and M. avium infection. FIG. 11C
represents inhibition of ISS induction of IDO by L-tryptophan or
1-methyl-DL-tryptophan (a competitive IDO inhibitor). L-Try,
L-tryptophan; M-Try, 1-methyl-DL-tryptophan. Results shown are
mean.+-.SD for triplicate experiments. *p<0.01 compared to CFU
recovered from cells treated with ISS-ODN.
DETAILED DESCRIPTION OF THE INVENTION
[0033] Before the present invention is described, it is to be
understood that this invention is not limited to particular
embodiments described, as such may, of course, vary. It is also to
be understood that the terminology used herein is for the purpose
of describing particular embodiments only, and is not intended to
be limiting, since the scope of the present invention will be
limited only by the appended claims.
[0034] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this invention belongs. Although
any methods and materials similar or equivalent to those described
herein can be used in the practice or testing of the present
invention, the preferred methods and materials are now described.
All publications mentioned herein are incorporated herein by
reference to disclose and describe the methods and/or materials in
connection with which the publications are cited.
[0035] It must be noted that as used herein and in the appended
claims, the singular forms "a", "and", and "the" include plural
referents unless the context clearly dictates otherwise. Thus, for
example, reference to "a cell" includes a plurality of such cells
and reference to "the polynucleotide" includes reference to one or
more polynucleotides and equivalents thereof known to those skilled
in the art, and so forth.
[0036] The publications discussed herein are provided solely for
their disclosure prior to the filing date of the present
application. Nothing herein is to be construed as an admission that
the present invention is not entitled to antedate such publication
by virtue of prior invention. Further, the dates of publication
provided may be different from the actual publication dates which
may need to be independently confirmed.
[0037] Definitions
[0038] As used herein, the term "pathogen" or "intracellular
pathogen" or "microbe" refers to any organism that exists within a
host cell, either in the cytoplasm or within a vacuole, for at
least part of its reproductive or life cycle. Intracellular
pathogens include viruses (e.g., CMV HIV), bacteria (e.g.,
Listeria, Mycobacteria, Salmonella (e.g., S. typhi)
enteropathogenic Escherichia coli (EPEC), enterohaemorrhagic
Escherichia coli (EHEC), Yersinia, Shigella, Chlamydia,
Chlamydophila, Staphylococcus, Legionella), protozoa (e.g.,
Taxoplasma), fungi, and intracellular parasites (e.g., Plasmodium
(e.g., P. vivax, P. falciparum, P. ovale, and P. malariae).
[0039] The terms "immunomodulatory nucleic acid molecule," "ISS,"
"ISS-PN," and "ISS-ODN, "used interchangeably herein, refer to a
polynucleotide that comprises at least one immunomodulatory nucleic
acid moiety. The term "immunomodulatory, "as used herein in
reference to a nucleic acid molecule, refers to the ability of a
nucleic acid molecule to modulate an immune response in a
vertebrate host.
[0040] The terms "oligonucleotide," "polynucleotide," and "nucleic
acid molecule", used interchangeably herein, refer to polymeric
forms of nucleotides of any length, either ribonucleotides or
deoxyribonucleotides. Thus, this term includes, but is not limited
to, single-, double-, or multi-stranded DNA or RNA, genomic DNA,
cDNA, DNA-RNA hybrids, or a polymer comprising purine and
pyrimidine bases or other natural, chemically or biochemically
modified, non-natural, or derivatized nucleotide bases. The
backbone of the polynucleotide can comprise sugars and phosphate
groups (as may typically be found in RNA or DNA), or modified or
substituted sugar or phosphate groups. Alternatively, the backbone
of the polynucleotide can comprise a polymer of synthetic subunits
such as phosphoramidites, and/or phosphorothioates, and thus can be
an oligodeoxynucleoside phosphoramidate or a mixed
phosphoramidate-phosphodiester oligomer. Peyrottes et al. (1996)
Nucl. Acids Res. 24:1841-1848; Chaturvedi et al. (1996) Nucl. Acids
Res. 24:2318-2323. The polynucleotide may comprise one or more
L-nucleosides. A polynucleotide may comprise modified nucleotides,
such as methylated nucleotides and nucleotide analogs, uracyl,
other sugars, and linking groups such as fluororibose and thioate,
and nucleotide branches. The sequence of nucleotides may be
interrupted by non-nucleotide components. A polynucleotide may be
modified to comprise N3'-P5' (NP) phosphoramidate, morpholino
phosphorociamidate (MF), lockaed nucleic acid (LNA),
2'-O-methoxyethyl (MOE), or 2'-fluoro, arabino-nucleic acid (FANA),
which can enhance the reistance of the polynucleotide to nuclease
degradation (see, e.g., Faria et al. (2001) Nature Biotechnol.
19:40-44; Toulme (2001) Nature Biotechnol. 19:17-18). A
polynucleotide may be further modified after polymerization, such
as by conjugation with a labeling component. Other types of
modifications included in this definition are caps, substitution of
one or more of the naturally occurring nucleotides with an analog,
and introduction of means for attaching the polynucleotide to
proteins, metal ions, labeling components, other polynucleotides,
or a solid support. Immunomodulatory nucleic acid molecules can be
provided in various formulations, e.g., in association with
liposomes, microencapsulated, etc., as described in more detail
herein.
[0041] The terms "polypeptide," "peptide," and "protein", used
interchangeably herein, refer to a polymeric form of amino acids of
any length, which can include coded and non-coded amino acids,
chemically or biochemically modified or derivatized amino acids,
and polypeptides having modified peptide backbones. The term
includes polypeptide chains modified or derivatized in any manner,
including, but not limited to, glycosylation, formylation,
cyclization, acetylation, phosphorylation, and the like. The term
includes naturally-occurring peptides, synthetic peptides, and
peptides comprising one or more amino acid analogs. The term
includes fusion proteins, including, but not limited to, fusion
proteins with a heterologous amino acid sequence, fusions with
heterologous and homologous leader sequences, with or without
N-terminal methionine residues; immunologically tagged proteins;
and the like.
[0042] As used herein the term "isolated" is meant to describe a
compound of interest that is in an environment different from that
in which the compound naturally occurs. "Isolated" is meant to
include compounds that are within samples that are substantially
enriched for the compound of interest and/or in which the compound
of interest is partially or substantially purified.
[0043] As used herein, the term "substantially purified" refers to
a compound that is removed from its natural environment and is at
least 60% free, preferably 75% free, and most preferably 90% free
from other components with which it is naturally associated.
[0044] "Treatment" or "treating" as used herein means any
therapeutic intervention in a subject, usually a mammalian subject,
generally a human subject, including: (i) prevention, that is,
causing the clinical symptoms not to develop, e.g., preventing
infection and/or preventing progression to a harmful state; (ii)
inhibition, that is, arresting the development or further
development of clinical symptoms, e.g., mitigating or completely
inhibiting an active (ongoing) infection so that pathogen load is.
decreased to the degree that it is no longer harmful, which
decrease can include complete elimination of an infectious dose of
the pathogen from the subject; and/or (iii) relief, that is,
causing the regression of clinical symptoms, e.g., causing a relief
of fever, inflammation, and/or other symptoms caused by an
infection.
[0045] As used herein, "immunoprotective response" is meant to
encompass humoral and/or cellular immune responses that are
sufficient to: 1) inhibit or prevent infection by an intracellular
pathogen, particularly Mycobacteria; and/or 2) prevent onset of
disease, reduce the risk of onset of disease, or reduce the
severity of disease symptoms caused by infection by an
intracellular pathogen, particularly Mycobacteria.
[0046] The term "effective amount" or "therapeutically effective
amount" means a dosage sufficient to provide for treatment for the
disease state being treated or to otherwise provide the desired
effect (e.g., induction of an effective immune response). The
precise dosage will vary according to a variety of factors such as
subject-dependent variables (e.g., age, immune system health,
etc.), the disease (e.g., the species of the infecting pathogen),
and the treatment being effected. In the case of an intracellular
pathogen infection, an "effective amount" is that amount necessary
to substantially improve the likelihood of treating the infection,
in particular that amount which improves the likelihood of
successfully preventing infection or eliminating infection when it
has occurred.
[0047] By "subject" or "individual" or "patient" is meant any
subject for whom or which therapy is desired. Human subjects are of
particular interest. Other subjects may include non-human primates,
cattle, sheep, goats, dogs, cats, birds (e.g., chickens or other
poultry), guinea pigs, rabbits, rats, mice, horses, and so on. Of
particular interest are subjects having or susceptible to
intracellular pathogen infection, particularly mycobacterial
infection, more particularly to infection by M. tuberculosis, M.
avium, and the like.
[0048] Overview
[0049] The invention is based on the discovery that: 1)
administration of immunomodulatory nucleic acid molecules results
in induction of an immune response protective against infection by
mycobacteria; 2) immunomodulatory nucleic acid molecules act as a
chemotherapeutic agent (as evidenced by, for example, the ability
of immunomodulatory nucleic acid molecules to inhibit growth of
mycobacteria when administered alone); 3) immunomodulatory nucleic
acid molecules provide a synergistic effect when administered with
another chemotherapeutic agent; and 4) administration of
immunomodulatory nucleic acid molecules results in induction of
indoleamine 2,3-dioxygenase (IDO), indicating immunomodulatory
nucleic acid molecules have activity against a wide range of
intracellular pathogens that utilize L-tryptophan of the host cell.
In short, immunomodulatory nucleic acid molecule administration
results in activation of the subject's innate immunity and
induction of IDO synthesis, takes advantage of chemotherapeutic
activity of the immunomodulatory nucleic acid molecules, and can
thus modify the course of infection by an intracellular
pathogen.
[0050] Various aspects of the invention will now be described in
more detail.
[0051] Nucleic Acid Molecules Comprising Immunomodulatory Nucleic
Acid Molecule
[0052] Immunomodulatory nucleic acid molecules are polynucleotides
that modulate activity of immune cells, especially immune cell
activity associated with a type-1 (Th1-mediated) or type-1 like
immune response. Furthermore, immunomodulatory nucleic acid
molecules of the present invention encompass polynucleotides that
inhibit replication of intracellular pathogens (e.g., inhibit
intracellular mycobacterial replication.).
[0053] Nucleic acid molecules comprising an immunomodulatory
nucleic acid molecule which are suitable for use in the methods of
the invention include an oligonucleotide, which can be a part of a
larger nucleotide construct such as a plasmid. The term
"polynucleotide" therefore includes oligonucleotides, modified
oligonucleotides and oligonucleosides, alone or as part of a larger
construct. The polynucleotide can be single-stranded DNA (ssDNA),
double-stranded DNA (dsDNA), single-stranded RNA (ssRNA) or
double-stranded RNA (dsRNA). The polynucleotide portion can be
linearly or circularly configured, or the oligonucleotide portion
can contain both linear and circular segments. Immunomodulatory
nucleic acid molecules also encompasses crude, detoxified bacterial
(e.g., mycobacterial) RNA or DNA, as well as ISS-enriched plasmids.
"ISS-enriched plasmid" as used herein is meant to refer to a linear
or circular plasmid that comprises or is engineered to comprise a
greater number of CpG motifs than normally found in mammalian DNA.
Exemplary ISS-enriched plasmids are described in, for example,
Roman et al. (1997) Nat Med. 3(8):849-54. Modifications of
oligonucleotides include, but are not limited to, modifications of
the 3'OH or 5'OH group, modifications of the nucleotide base,
modifications of the sugar component, and modifications of the
phosphate group.
[0054] The immunomodulatory nucleic acid molecule can comprise
ribonucleotides (containing ribose as the only or principal sugar
component), deoxyribonucleotides (containing deoxyribose as the
principal sugar component), or in accordance with the established
state-of-the-art, modified sugars or sugar analogs may be
incorporated in the oligonucleotide of the present invention.
Examples of a sugar moiety that can be used include, in addition to
ribose and deoxyribose, pentose, deoxypentose, hexose, deoxyhexose,
glucose, arabinose, xylose, lyxose, and a sugar "analog"
cyclopentyl group. The sugar may be in pyranosyl or in a furanosyl
form. In the modified oligonucleotides of the present invention,
the sugar moiety is preferably the furanoside of ribose,
deoxyribose, arabinose or 2'-O-methylribose, and the sugar may be
attached to the respective heterocyclic bases either in I or J
anomeric configuration.
[0055] An immunomodulatory nucleic acid molecule may comprise at
least one nucleoside comprising an L-sugar. The L-sugar may be
deoxyribose, ribose, pentose, deoxypentose, hexose, deoxyhexose,
glucose, galactose, arabinose, xylose, lyxose, or a sugar "analog"
cyclopentyl group. The L-sugar may be in pyranosyl or furanosyl
form.
[0056] The phosphorous derivative (or modified phosphate group)
that can be attached to the sugar or sugar analog moiety in the
modified oligonucleotides of the present invention can be a
monophosphate, diphosphate, triphosphate, alkylphosphate,
alkanephosphate, phosphoronthioate, phosphorodithioate or the like.
The heterocyclic bases, or nucleic acid bases that are incorporated
in the oligonucleotide base of the ISS can be the naturally
occurring principal purine and pyrimidine bases, (namely uracil or
thymine, cytosine, adenine and guanine, as mentioned above), as
well as naturally occurring and synthetic modifications of said
principal bases. Those skilled in the art will recognize that a
large number of "synthetic" non-natural nucleosides comprising
various heterocyclic bases and various sugar moieties (and sugar
analogs) are available, and that the immunomodulatory nucleic acid
molecule can include one or several heterocyclic bases other than
the principal five base components of naturally occurring nucleic
acids. Preferably, however, the heterocyclic base in the ISS is
selected from uracil-5-yl, cytosin-5-yl, adenin-7-yl, adenin-8-yl,
guanin-7-yl, guanin-8-yl, 4-aminopyrrolo [2,3-d] pyrimidin-5-yl,
2-amino-4-oxopyrolo [2,3-d] pyrimidin-5-yl, 2-amino-4-oxopyrrolo
[2,3-d] pyrimidin-3-yl groups, where the purines are attached to
the sugar moiety of the oligonucleotides via the 9-position, the
pyrimidines via the 1-position, the pyrrolopyrimidines via the
7-position and the pyrazolopyrimidines via the 1-position.
[0057] Structurally, the root oligonucleotide of the
immunomodulatory nucleic acid molecule is a non-coding sequence
that can include at least one unmethylated CpG motif. The relative
position of any CpG sequence in ISS with immunomodulatory activity
in certain mammalian species (e.g., rodents) is 5'-CG-3' (i.e., the
C is in the 5' position with respect to the G in the 3'
position).
[0058] Immunomodulatory nucleic acid molecules generally do not
provide for, nor is there any requirement that they provide for,
expression of any amino acid sequence encoded by the
polynucleotide, and thus the sequence of a immunomodulatory nucleic
acid molecule may be, and generally is, non-coding.
Immunomodulatory nucleic acid molecules may comprise a linear
double or single-stranded molecule, a circular molecule, or can
comprise both linear and circular segments. Immunomodulatory
nucleic acid molecules may be single-stranded, or may be completely
or partially double-stranded.
[0059] In some embodiments, an immunomodulatory nucleic acid
molecule is an oligonucleotide, e.g., consists of a sequence of
from about 6 to about 200, from about 10 to about 100, from about
12 to about 50, or from about 15 to about 25, nucleotides in
length.
[0060] Exemplary consensus CpG motifs of immunomodulatory nucleic
acid molecules useful in the invention include, but are not
necessarily limited to:
[0061] 5'-Purine-Purine-[C]-[G]-Pyrimidine-Pyrimidine-3', in which
the immunomodulatory nucleic acid molecule comprises a CpG motif
flanked by at least two purine nucleotides (e.g., GG, GA, AG, AA,
II, etc.,) and at least two pyrimidine nucleotides (CC, TT, CT, TC,
UU, etc.);
[0062] 5'-Purine-TCG-Pyrimidine-Pyrimidine-3';
[0063] 5'-[TCG].sub.n-3', where n is any integer that is 1 or
greater, e.g., to provide a poly-TCG immunomodulatory nucleic acid
molecule (e.g., where n=3, the polynucleotide comprises the
sequence 5'-TCGTCGTCG-3'); and
[0064] 5'-Purine-Purine-CG-Pyrimidine-Pyrimidine-CG-3'.
[0065] 5'-Purine-TCG-Pyrimidine-Pyrimidine-CG-3'
[0066] Exemplary DNA-based immunomodulatory nucleic acid molecules
useful in the invention include, but are not necessarily limited
to, polynucleotides comprising the following nucleotide
sequences:
1 AACGCC, AACGCT, AACGTC, AACGTT; AGCGCC, AGCGCT, AGCGTC, AGCGTT;
GACGCC, GACGCT, GACGTC, GACGTT; GGCGCC, GGCGCT, GGCGTC, GGCGTT;
ATCGCC, ATCGCT, ATCGTC, ATCGTT; GTCGCC, GTCGCT, GTCGTC, GTCGTT; and
TCGTCG, and TCGTCGTCG.
[0067] Octameric sequences are generally the above-mentioned
hexameric sequences, with an additional 3'CG. Exemplary DNA-based
immunomodulatory nucleic acid molecules useful in the invention
include, but are not necessarily limited to, polynucleotides
comprising the following octameric nucleotide sequences:
2 AACGCCCG, AACGCTCG, AACGTCCG, AACGTTCG; AGCGCCCG, AGCGCTCG,
AGCGTCCG, AGCGTTCG; GACGCCCG, GACGCTCG, GACGTCCG, GACGTTCG;
GGCGCCCG, GGCGCTCG, GGCGTCCG, GGCGTTCG; ATCGCCCG, ATCGCTCG,
ATCGTCCG, ATCGTTCG; GTCGCCCG, GTCGCTCG, GTCGTCCG, and GTCGTTCG.
[0068] Immunomodulatory nucleic acid molecules useful in the
invention can comprise one or more of any of the above CpG motifs.
For example, immunomodulatory nucleic acid molecules useful in the
invention can comprise a single instance or multiple instances
(e.g., 2, 3, 5 or more) of the same CpG motif. Alternatively, the
immunomodulatory nucleic acid molecules can comprises multiple CpG
motifs (e.g., 2, 3, 5 or more) where at least two of the multiple
CpG motifs have different consensus sequences, or where all CpG
motifs in the immunomodulatory nucleic acid molecules have
different consensus sequences.
[0069] A non-limiting example of an immunomodulatory nucleic acid
molecule is one with the sequence 5'-TGACTGTGAACGTTCGAGATGA-3' (SEQ
ID NO: 1). An example of a control nucleic acid molecule is one
having the sequence 5'-TGACTGTGAAgGTTCGAGATGA-3' (SEQ ID NO:2),
which differs from SEQ ID NO: 1 at the nucleotide indicated in
lower case type.
[0070] Immunomodulatory nucleic acid molecules useful in the
invention may or may not include palindromic regions. If present, a
palindrome may extend only to a CpG motif, if present, in the core
hexamer or octamer sequence, or may encompass more of the hexamer
or octamer sequence as well as flanking nucleotide sequences.
[0071] The core hexamer structure of the foregoing immunomodulatory
nucleic acid molecules can be flanked upstream and/or downstream by
any number or composition of nucleotides or nucleosides. However,
ISS are at least 6 bases in length, and preferably are between 6
and 200 bases in length, to enhance uptake of the immunomodulatory
nucleic acid molecule into target tissues.
[0072] In particular, immunomodulatory nucleic acid molecules
useful in the invention include those that have hexameric
nucleotide sequences having "CpG" motifs. Although DNA sequences
are generally preferred, RNA immunomodulatory nucleic acid
molecules can be used, with inosine and/or uracil substitutions for
nucleotides in the hexamer sequences.
[0073] Modifications
[0074] Immunomodulatory nucleic acid molecules can be modified in a
variety of ways. For example, the immunomodulatory nucleic acid
molecules can comprise backbone phosphate group modifications
(e.g., methylphosphonate, phosphorothioate, phosphoroamidate and
phosphorodithioate internucleotide linkages), which modifications
can, for example, enhance stability of the immunomodulatory nucleic
acid molecule in vivo, making them particularly useful in
therapeutic applications. A particularly useful phosphate group
modification is the conversion to the phosphorothioate or
phosphorodithioate forms of an immunomodulatory nucleic acid
molecule. Phosphorothioates and phosphorodithioates are more
resistant to degradation in vivo than their unmodified
oligonucleotide counterparts, increasing the half-lives of the
immunomodulatory nucleic acid molecules and making them more
available to the subject being treated.
[0075] Other modified immunomodulatory nucleic acid molecules
encompassed by the present invention include immunomodulatory
nucleic acid molecules having modifications at the 5' end, the 3'
end, or both the 5' and 3' ends. For example, the 5' and/or 3' end
can be covalently or non-covalently conjugated to a molecule
(either nucleic acid, non-nucleic acid, or both) to, for example,
increase the bio-availability of the immunomodulatory nucleic acid
molecules, increase the efficiency of uptake where desirable,
facilitate delivery to cells of interest, and the like. Exemplary
molecules for conjugation to the immunomodulatory nucleic acid
molecules include, but are not necessarily limited to, cholesterol,
phospholipids, fatty acids, sterols, oligosaccharides, polypeptides
(e.g., immunoglobulins), peptides, antigens (e.g., peptides, small
molecules, etc.), linear or circular nucleic acid molecules (e.g.,
a plasmid), and the like. Additional immunomodulatory nucleic acid
conjugates, and methods for making same, are known in the art and
described in, for example, WO 98/16427 and WO 98/55495. Thus, the
term "immunomodulatory nucleic acid molecule" includes conjugates
comprising an immunomodulatory nucleic acid molecule.
[0076] Preparation of Immunomodulatory Nucleic Acid Molecules
[0077] Immunomodulatory nucleic acid molecules can be synthesized
using techniques and nucleic acid synthesis equipment well known in
the art (see, e.g., Ausubel et al. Current Protocols in Molecular
Biology, (Wiley Intersicence, 1989); Maniatis et al. Molecular
Cloning: A Laboratory Manual (Cold Spring Harbor Laboratories, New
York, 1982); and U.S. Pat. Nos. 4,458,066; and 4,650,675.
Individual polynucleotide fragments can be ligated with a ligase
such as T4 DNA or RNA ligase as described in , e.g., U.S. Pat. No.
5,124,246. Oligonucleotide degradation can be accomplished through
exposure to a nuclease, see, e.g., U.S. Pat. No. 4,650,675. As
noted above, since the immunomodulatory nucleic acid molecules need
not provide for expression of any encoded amino acid sequence, the
invention does not require that the immunomodulatory nucleic acid
molecules be operably linked to a promoter or otherwise provide for
expression of a coding sequence.
[0078] Alternatively, immunomodulatory nucleic acid molecules can
be isolated from microbial species (e.g., mycobacteria) using
techniques well known in the art such as nucleic acid
hybridization, amplification (e.g., by PCR), and the like. Isolated
immunomodulatory nucleic acid molecules can be purified to a
substantially pure state, e.g., free of endogenous contaminants,
e.g., lipopolysaccharides. Immunomodulatory nucleic acid molecules
isolated as part of a larger polynucleotide can be reduced to the
desired length by techniques well known in the art, such as
endonuclease digestion. Other techniques suitable for isolation,
purification, and production of polynucleotides to obtain ISS will
be readily apparent to the ordinarily skilled artisan in the
relevant field.
[0079] Circular immunomodulatory nucleic acid molecules can also be
synthesized through recombinant methods or chemically synthesized.
Where circular immunomodulatory nucleic acid molecules are obtained
through isolation or recombinant methods, the immunomodulatory
nucleic acid molecule can be provided as a plasmid. Chemical
synthesis of smaller circular oligonucleotides can be performed
using methods known in the art (see, e.g., Gao et al. (1995) Nucl.
Acids. Res. 23:2025-9; Wang et al., (1994) Nucl. Acids Res.
22:2326-33).
[0080] Where the immunomodulatory nucleic acid molecule comprises a
modified oligonucleotide, the modified oligonucleotides can be
synthesized using standard chemical techniques. For example,
solid-support based construction of methylphosphonates has been
described in Agrawal et al. Tet. Lett. 28:3539-42. Synthesis of
other phosphorous-based modified oligonucleotides, such as
phosphotriesters (see, e.g., Miller et al. (1971) J. Am Chem Soc.
93:6657-65), phosphoramidates (e.g., Jager et al. (1988) Biochem.
27:7237-46), and phosphorodithioates (e.g., U.S. Pat. No.
5,453,496) is known in the art. Other non-phosphorous-based
modified oligonucleotides can also be used (e.g., Stirchak et al.
(1989) Nucl. Acids. Res. 17:6129-41).
[0081] Preparation of base-modified nucleosides, and the synthesis
of modified oligonucleotides using such base-modified nucleosides
as precursors is well known in the art, see, e.g., U.S. Pat. Nos.
4,910,300; 4,948,882; and 5,093,232. These base-modified
nucleosides have been designed so that they can be incorporated by
chemical synthesis into either terminal or internal positions of an
oligonucleotide. Nucleosides modified in their sugar moiety have
also been described (see, e.g., U.S. Pat. Nos. 4,849,513;
5,015,733; 5,118,800; and 5,118,802).
[0082] Techniques for making phosphate group modifications to
oligonucleotides are known in the art. Briefly, an intermediate
phosphate triester for the target oligonucleotide product is
prepared and oxidized to the naturally-occurring phosphate triester
with aqueous iodine or other agents, such as anhydrous amines. The
resulting oligonucleotide phosphoramidates can be treated with
sulfur to yield phosphorothioates. The same general technique
(without the sulfur treatment step) can be used to produced
methylphosphoamidites from methylphosphonates. Techniques for
phosphate group modification are well known and are described in,
for example, U.S. Pat. Nos. 4,425,732; 4,458,066; 5,218,103; and
5,453,496.
[0083] Identification of Immunomodulatory Nucleic Acid
Molecules
[0084] Confirmation that a particular compound has the properties
of an immunomodulatory nucleic acid molecule useful in the
invention can be obtained by evaluating whether the
immunomodulatory nucleic acid molecule elicits the appropriate
cytokine secretion patterns, e.g., a cytokine secretion pattern
associated with a type-i imrnune response; inhibits intracellular
pathogen replication, e.g., inhibits intracellular growth of
intracellular pathogens either in vitro or in vivo; and/or
modulates intracellular availability of cellular products necessary
for growth and/or reproduction of the intracellular pathogen, e.g.,
reduces intracellular levels of L-tryptophan, for example, by
inducing expression of indoleamine 2,3-dioxygenase (IDO) in a cell.
ISS delivered with an antigen also induces activity of cytotoxic T
cells and acts as a very strong mucosal adjuvant (see, e.g., Horner
(1998) Cell. Immunol. 190:77-82). As noted above, immunomodulatory
nucleic acid molecules of interest in the methods of the invention
are those that elicit a Th1-mediated response, those that induce
expression of IDO, and those that inhibit intracellular growth of
intracellular pathogens, particularly intracellular growth of
mycobacteria, more particularly intracellular mycobacterial growth
in macrophages, especially monocyte-derived macrophages and bone
marrow-derived macrophages.
[0085] In general, helper T (Th) cells are divided into broad
groups based on their specific profiles of cytokine production:
Th1, Th2, and ThO. "Th1 " cells are T lymphocytes that release
predominantly the cytokines IL-2 and IFN-.gamma., which cytokines
in turn promote T cell proliferation, facilitate macrophage
activation, and enhance the cytolytic activity of natural killer
(NK) cells and antigen-specific cytotoxic T cells (CTL). In
contrast, the cytokines predominantly released by Th2 cells are
IL-4, IL-5, and IL-10. IL-4 and IL-5 are known to mediate antibody
isotype switching towards IgE or IgA response, and promote
eosinophil recruitment, skewing the immune system toward an
"allergic" type of response. ThO cells release a set of cytokines
with characteristics of both Th1-type and Th2-type responses. While
the categorization of T cells as Th1, TH2, or Th0 is helpful in
describing the differences in immune response, it should be
understood that it is more accurate to view the T cells and the
responses they mediate as forming a continuum, with Th1 and Th2
cells at opposite ends of the scale, and ThO cells providing the
middle of the spectrum. Therefore, it should be understood that the
use of these terms herein is only to describe the predominant
nature of the immune response elicited, and is not meant to be
limiting to an immune response that is only of the type indicated.
Thus, for example, reference to a "type-1" or "Th1" immune response
is not meant to exclude the presence of a "type-2" or "Th2" immune
response, and vice versa.
[0086] Details of in vitro and in vivo techniques useful for
evaluation of production of cytokines associated with a type-1 or
type2 response, as well as for evaluation of antibody production,
are well known in the art. Likewise, methods for evaluating the
ability of candidate ISS to inhibit intracellular pathogen growth
are also well known in the art, and are further exemplified in the
Examples below.
[0087] Administration of Immunomodulatory Nucleic Acid
Molecules
[0088] Immunomodulatory nucleic acid molecules are administered to
an individual using any available method and route suitable for
drug delivery, including in vivo and ex vivo methods, as well as
systemic, mucosal, and localized routes of administration.
[0089] Conventional and pharmaceutically acceptable routes of
administration include intranasal, intramuscular, intratracheal,
subcutaneous, intradermal, topical application, intravenous,
rectal, nasal, oral and other parenteral routes of administration.
Routes of administration may be combined, if desired, or adjusted
depending upon the immunomodulatory nucleic acid molecule and/or
the desired effect on the immune response. The immunomodulatory
nucleic acid composition can be administered in a single dose or in
multiple doses, and may encompass administration of booster doses,
to elicit and/or maintain the desired effect on the immune
response.
[0090] Immunomodulatory nucleic acid molecules can be administered
to a subject using any available conventional methods and routes
suitable for delivery of conventional drugs, including systemic or
localized routes. Methods and localized routes that further
facilitate production of a type-1 or type-1-like response and/or
the anti-pathogenic (e.g. anti-mycobacterial) activity of the
immunomodulatory nucleic acid molecules, particularly at or near a
site of intracellular pathogen infection (e.g., within the lungs)
is of interest in the invention, and may be preferred over systemic
routes of administration, both for the immediacy of therapeutic
effect and avoidance of in vivo degradation of the administered
immunomodulatory nucleic acid molecules. In general, routes of
administration contemplated by the invention include, but are not
necessarily limited to, enteral, parenteral, or inhalational
routes. Inhalational routes may be preferred in cases of pulmonary
involvement, particularly in view of the activity of
immunomodulatory nucleic acid molecules as a mucosal adjuvant.
[0091] Inhalational routes of administration (e.g., intranasal,
intrapulmonary, and the like) are particularly useful in
stimulating an immune response for prevention or treatment of
intracellular pathogen infections of the respiratory tract. Such
means include inhalation of aerosol suspensions or insufflation of
the polynucleotide compositions of the invention. Nebulizer
devices, metered dose inhalers, and the like suitable for delivery
of polynucleotide compositions to the nasal mucosa, trachea and
bronchioli are well-known in the art and will therefore not be
described in detail here. For. general review in regard to
intranasal drug delivery, see, e.g., Chien, Novel Drug Delivery
Systems, Ch. 5 (Marcel Dekker, 1992).
[0092] Parenteral routes of administration other than inhalation
administration include, but are not necessarily limited to,
topical, transdermal, subcutaneous, intramuscular, intraorbital,
intracapsular, intraspinal, intrasternal, and intravenous routes,
i.e., any route of administration other than through the alimentary
canal. Parenteral administration can be carried to effect systemic
or local delivery of immunomodulatory nucleic acid molecules. Where
systemic delivery is desired, administration typically involves
invasive or systemically absorbed topical or mucosal administration
of pharmaceutical preparations.
[0093] Immunomodulatory nucleic acid molecules can also be
delivered to the subject by enteral administration. Enteral routes
of administration include, but are not necessarily limited to, oral
and rectal (e.g., using a suppository) delivery.
[0094] Methods of administration of immunomodulatory nucleic acid
molecules through the skin or mucosa include, but are not
necessarily limited to, topical application of a suitable
pharmaceutical preparation, transdermal transmission, injection and
epidermal administration. For transdermal transmission, absorption
promoters or iontophoresis are suitable methods. For review
regarding such methods, those of ordinary skill in the art may wish
to consult Chien, supra at Ch. 7. lontophoretic transmission may be
accomplished using commercially available "patches" which deliver
their product continuously via electric pulses through unbroken
skin for periods of several days or more. An exemplary patch
product for use in this method is the LECTRO PATCH.TM.
(manufactured by General Medical Company, Los Angeles, Calif.)
which electronically maintains reservoir electrodes at neutral pH
and can be adapted to provide dosages of differing concentrations,
to dose continuously and/or to dose periodically.
[0095] Epidermal administration can be accomplished by mechanically
or chemically irritating the outermost layer of the epidermis
sufficiently to provoke an immune response to the irritant. An
exemplary device for use in epidermal administration employs a
multiplicity of very narrow diameter, short tynes which can be used
to scratch ISS coated onto the tynes into the skin. The device
included in the MONO-VACC.TM. tuberculin test (manufactured by
Pasteur Merieux, Lyon, France) is suitable for use in epidermal
administration of immunomodulatory nucleic acid molecules.
[0096] The invention also contemplates opthalmic administration of
immunomodulatory nucleic acid molecules, which generally involves
invasive or topical application of a pharmaceutical preparation to
the eye. Eye drops, topical cremes and injectable liquids are all
examples of suitable formulations for delivering drugs to the
eye.
[0097] Immunomodulatory nucleic acid molecules can be administered
to a subject prior to exposure to intracellular pathogen, after
exposure to intracellular pathogen but prior to onset of disease
symptoms associated with infection, or after intracellular pathogen
infection or onset of disease symptoms. As such, immunomodulatory
nucleic acids can be administered at any time after exposure to
intracellular pathogen, but a first dose is usually administered
about 8 hours, about 12 hours, about 24 hours, about 2 days, about
4 days, about 8 days, about 16 days, about 30 days or 1 month,
about 2 months, about 4 months, about 8 months, or about 1 year
after exposure to intracellular pathogen. As described in more
detail below, the invention also provides for administration of
subsequent doses of immunomodulatory nucleic acid molecules.
[0098] Administration With Additional Chemotherapeutic Agents
[0099] In one embodiment, immunomodulatory nucleic acid molecules
are administered in combination with a conventional anti-pathogenic
agent to provide for a synergistic effect in treatment of
intracellular pathogen infection. The additional anti-pathogenic
agent may be any agent (e.g., chemotherapeutic agent) identified as
having activity against the intracellular pathogen of interest
(e.g., in inhibition of extracellular or intracellular growth
stages of the intracellular pathogen (e.g., mycobacteria),
enhancement of intracellular pathogen clearance (e.g.,
mycobacteria), etc.). Exemplary anti-pathogenic agents include, but
are not necessarily limited to, antibiotics, including
antimicrobial agents, (e.g., bacteriostatic and bacteriocidal
agents (e.g., aminoglycosides, .beta.-lactam antibiotics,
cephalosporins, macrolides, penicillins, tetracyclines, quinolones,
and the like ), antivirals (e.g., amprenavirs, acyclovirs,
amantadines, virus penciclovirs, and the like), and the like),
antifungals, (e.g., imidazoles, triazoles, allylamines, polyenes,
and the like), as well as anti-parasitic agents (e.g., atovaquones,
chloroquines, pyrimethamines, ivermectins, mefloquines,
pentamidines, primaquines, and the like). Where the subject being
treated is particularly susceptible to infection by intracellular
pathogens, including opportunistic pathogens, it may be desirable
to administer immunomodulatory nucleic acid molecules in a
combination therapeutic regimen with chemotherapeutic agents that
exhibit activity against microbial and/or parasitic pathogens,
e.g., antimicrobial agents, antiviral agents, antifungal agents,
anti-parasitic agents, etc. Such combination therapies can involve
simultaneous or consecutive administration of ISS and such a
chemotherapeutic agent(s).
[0100] Specific exemplary conventional
anti-pathogenic/chemotherapeutic agents and combinatory therapies,
particularly anti-mycobacterial agents and combinatory therapies,
include, but are not necessarily limited to, clarithromycin (e.g.,
by oral administration or injection); capreomycin sulfate (e.g., by
intramuscular injection or intravenous infusion, e.g.
CAPASTAT.RTM.); ethambutol HCl (e.g., by oral administration of
tablets or capsules, e.g., MYAMBUTOL.RTM.); isoniazid (e.g., by
intramuscular injection or oral administration, e.g.,
NYDRAZID.RTM.; aminosalicylic acid (e.g., aminosalicyclic acid
granules for oral administration, e.g., PASER.RTM.GRANULES);
rifapentine (e.g., by oral administration; e.g., PRIFTIN.RTM.);
PYRAZINAMIDE (e.g., by oral administration); rifampin (e.g., by
oral administration, e.g., RIFADIN.RTM., or by intravenous
administration, e.g., RIFADIN IV.RTM.); rifampin and isoniazid
combination therapy (e.g., by oral administration, e.g.,
RIFAMATE.RTM.); rifampin, isoniazid, and pyrazinamide combination
therapy (e.g., by oral administration, e.g., RIFATER.RTM.);
cycloserine (e.g., by oral administration, e.g., SEROMYCIN.RTM.;
streptomycin sulfate (e.g., by injection or oral administration);
ethionamide (e.g., by oral administration, e.g., TRECATOR.RTM.-SC),
and the like.
[0101] The anti-pathogenic/chemotherapeutic agent and
immunomodulatory nucleic acid molecule can be administered within
the same or different formulation; by the same or different routes;
or concurrently, simultaneously, or consecutively. The
immunomodulatory nucleic acid molecule can be delivered according
to a regimen (e.g., frequency during a selected interval (e.g.,
number of times per day), delivery route, etc.) that is the same
as, similar to, or different from that of the anti-pathogenic
agent. When administered in combination, ISS and an anti-pathogenic
agent are generally administered within about 96 hours, about 72
hours, about 48 hours, about 24 hours, about 12 hours, about 8
hours, about 4 hours, about 2 hours, about 1 hour, or about 30
minutes or less, of each other. Thus, although it may be desirable
to do so in some situations, it is not necessarily required that
ISS and an anti-pathogenic agent (e.g., antibacterial agent) be
delivered simultaneously.
[0102] Dosages
[0103] One particular advantage of the use of immunomodulatory
nucleic acid molecules in the methods of the invention is. that
immunomodulatory nucleic acid molecules exert immunomodulatory and
anti-pathogenic activity even at relatively low dosages. Although
the dosage used will vary depending on the clinical goals to be
achieved, a suitable dosage range is one which provides up to about
1 .mu.g, to about 1,000 .mu.g, to about 10,000 .mu.g, to about
25,000 .mu.g or about 50,000 .mu.g of ISS. Immunomodulatory nucleic
acid molecules can be administered in a single dosage or several
smaller dosages over time. Alternatively, a target dosage of ISS
can be considered to be about 1-10,uM in a sample of host blood
drawn within the first 24-48 hours after administration of ISS.
Based on current studies, immunomodulatory nucleic acid molecules
are believed to have little or no toxicity at these dosage
levels.
[0104] It should be noted that the immunotherapeutic activity of
immunomodulatory nucleic acid molecules in the invention is
essentially dose-dependent. Therefore, to increase ISS potency by a
magnitude of two, each single dose is doubled in concentration.
Increased dosages may be needed to achieve the desired therapeutic
goal. The invention thus contemplates administration of "booster"
doses to provide and maintain an immune response effective to
protect the subject from infection or to inhibit infection; to
reduce the risk of the onset of disease or the severity of disease
symptoms that may occur as a result of infection; to facilitate
reduction of intracellular pathogen load; and/or to facilitate
clearance of infecting intracellular pathogen from the subject
(e.g., to facilitate clearance of organisms from the lungs). When
multiple doses are administered, subsequent doses are administered
within-about 16 weeks, about 12 weeks, about 8 weeks, about 6
weeks, about 4 weeks, about 2 weeks, about 1 week, about 5 days,
about 72 hours, about 48 hours, about 24 hours, about 12 hours,
about 8 hours, about 4 hours, or about 2 hours or less of the
previous dose. In one embodiment, ISS are administered at intervals
ranging from at least every two weeks to every four weeks (e.g.,
monthly intervals) in order to maintain the maximal immune response
against intracellular pathogen infection (e.g., mycobacterial
infection).
[0105] In view of the teaching provided by this disclosure, those
of ordinary skill in the clinical arts will be familiar with, or
can readily ascertain, suitable parameters for administration of
ISS according to the invention.
[0106] Formulations
[0107] In general, immunomodulatory nucleic acid molecules are
prepared in a pharmaceutically acceptable composition for delivery
to a host. Pharmaceutically acceptable carriers preferred for use
with the ISS of the invention may include sterile aqueous of
non-aqueous solutions, suspensions, and emulsions. Examples of
non-aqueous solvents are propylene glycol, polyethylene glycol,
vegetable oils such as olive oil, and injectable organic esters
such as ethyl oleate. Aqueous carriers include water,
alcoholic/aqueous solutions, emulsions or suspensions, including
saline and buffered media. Parenteral vehicles include sodium
chloride solution, Ringer's dextrose, dextrose and sodium chloride,
lactated Ringer's or fixed oils. Intravenous vehicles include fluid
and nutrient replenishers, electrolyte replenishers (such as those
based on Ringer's dextrose), and the like. A composition of ISS may
also be lyophilized using means well known in the art, for
subsequent reconstitution and use according to the invention. Also
of interest are formulations for liposomal delivery, and
formulations comprising microencapsulated immunomodulatory nucleic
acid molecules.
[0108] In general, the pharmaceutical compositions can be prepared
in various forms, such as granules, tablets, pills, suppositories,
capsules, suspensions, salves, lotions and the like. Pharmaceutical
grade organic or inorganic carriers and/or diluents suitable for
oral and topical use can be used to make up compositions comprising
the therapeutically-active compounds. Diluents known to the art
include aqueous media, vegetable and animal oils and fats.
Stabilizing agents, wetting and emulsifying agents, salts for
varying the osmotic pressure or buffers for securing an adequate pH
value, and skin penetration enhancers can be used as auxiliary
agents. Preservatives and other additives may also be present such
as, for example, anti-pathogenic agents (e.g., antimicrobials,
antibacterials, antivirals, antifungals, etc.), antioxidants,
chelating agents, and inert gases and the like. In one embodiment,
as discussed above, the immunomodulatory nucleic acid molecule
formulation comprises an additional anti-pathogenic agent.
Exemplary anti-pathogenic agents include, but are not necessarily
limited to, antibiotics, including antimicrobial agents (e.g.,
bacteriostatic and bacteriocidal agents (e.g., aminoglycosides,
.beta.-lactam antibiotics, cephalosporins, macrolides, penicillins,
tetracyclines, quinolones, and the like ), antivirals (e.g.,
amprenavirs, acyclovirs, amantadines, virus penciclovirs, and the
like), and the like), antifungals, (e.g., imidazoles, triazoles,
allylamines, polyenes, and the like), as well as anti-parasitic
agents (e.g., atovaquones, chloroquines, pyrimethamines,
ivermectins, mefloquines, pentamidines, primaquines, and the like).
In another embodiment, the anti-pathogenic agent is an
anti-mycobacterial agent (e.g., clarithromycin; capreomycin
sulfate; ethambutol HCl; isoniazid; aminosalicylic acid;
rifapentine; PYRAZINAMIDE; rifampin; rifampin and isoniazid in
combination; rifampin, isoniazid, and pyrazinamide in combination;
cycloserine; streptomycin sulfate; ethionamide; and the like).
[0109] Immunomodulatory nucleic acid molecules can be administered
in the absence of agents or compounds that might facilitate uptake
by target cells (e.g., as a "naked" polynucleotide, e.g., a
polynucleotide that is not encapsulated by a viral particle).
Immunomodulatory nucleic acid molecules can also be administered
with compounds that facilitate uptake of immunomodulatory nucleic
acid molecules by target cells (e.g., by macrophages) or otherwise
enhance transport of the immunomodulatory nucleic acid molecules to
a treatment site for action. Absorption promoters, detergents and
chemical irritants (e.g., keratinolytic agents) can enhance
transmission of an immunomodulatory nucleic acid molecule
composition into a target tissue (e.g., through the skin). For
general principles regarding absorption promoters and detergents
which have been used with success in mucosal delivery of organic
and peptide-based drugs, see, e.g., Chien, Novel Drug Delivery
Systems, Ch. 4 (Marcel Dekker, 1992). Examples of suitable nasal
absorption promoters in particular are set forth at Chien, supra at
Ch. 5, Tables 2 and 3; milder agents are preferred. Suitable agents
for use in the method of this invention for mucosal/nasal delivery
are also described in Chang, et al., Nasal Drug Delivery, "Treatise
on Controlled Drug Delivery", Ch. 9 and Tables 3-4B thereof,
(Marcel Dekker, 1992). Suitable agents which are known to enhance
absorption of drugs through skin are described in Sloan, Use of
Solubility Parameters from Regular Solution Theory to Describe
Partitioning-Driven Processes, Ch. 5, "Prodrugs: Topical and Ocular
Drug Delivery" (Marcel Dekker, 1992), and at places elsewhere in
the text. All of these references are incorporated herein for the
sole purpose of illustrating the level of knowledge and skill in
the art concerning drug delivery techniques.
[0110] A colloidal dispersion system may be used for targeted
delivery of immunomodulatory nucleic acid molecules to specific
tissue. Colloidal dispersion systems include macromolecule
complexes, nanocapsules, microspheres, beads, and lipid-based
systems including oil-in-water emulsions, micelles, mixed micelles,
and liposomes.
[0111] Liposomes are artificial membrane vesicles which are useful
as delivery vehicles in vitro and in vivo. It has been shown that
large unilamellar vesicles (LUV), which range in size from 0.2-4.0
.mu.m can encapsulate a substantial percentage of an aqueous buffer
containing large macromolecules. RNA and DNA can be encapsulated
within the aqueous interior and be delivered to cells in a
biologically active form (Fraley, et al., (1981) Trends Biochem.
Sci., 6:77). The composition of the liposome is usually a
combination of phospholipids, particularly
high-phase-transition-temperature phospholipids, usually in
combination with steroids, especially cholesterol. Other
phospholipids or other lipids may also be used. The physical
characteristics of liposomes depend on pH, ionic strength, and the
presence of divalent cations. Examples of lipids useful in liposome
production include phosphatidyl compounds, such as
phosphatidylglycerol, phosphatidylcholine, phosphatidylserine,
phosphatidylethanolamine, sphingolipids, cerebrosides, and
gangliosides. Particularly useful are diacylphosphatidylglycerols,
where the lipid moiety contains from 14-18 carbon atoms,
particularly from 16-18 carbon atoms, and is saturated.
Illustrative phospholipids include egg phosphatidylcholine,
dipalmitoylphosphatidylcholine and
distearoylphosphatidylcholine.
[0112] Where desired, targeting of liposomes can be classified
based on anatomical and mechanistic factors. Anatomical
classification is based on the level of selectivity, for example,
organ-specific, cell-specific, and organelle-specific. Mechanistic
targeting can be distinguished based upon whether it is passive or
active. Passive targeting utilizes the natural tendency of
liposomes to distribute to cells of the reticulo-endothelial system
(RES) in organs which contain sinusoidal capillaries. Active
targeting, on the other hand, involves alteration of the liposome
by coupling the liposome to a specific ligand such as a monoclonal
antibody, sugar, glycolipid, or protein, or by changing the
composition or size of the liposome in order to achieve targeting
to organs and cell types other than the naturally occurring sites
of localization.
[0113] The surface of the targeted delivery system may be modified
in a variety of ways. In the case of a liposomal targeted delivery
system, lipid groups can be incorporated into the lipid bilayer of
the liposome in order to maintain the targeting ligand in stable
association with the liposomal bilayer. Various well known linking
groups can be used for joining the lipid chains to the targeting
ligand (see, e.g., Yanagawa, et al., (1988) Nuc. Acids Symp. Ser.,
19:189; Grabarek, et al., (1990) Anal. Biochem., 185:131; Staros,
et al., (1986) Anal. Biochem. 156:220 and Boujrad, et al., (1993)
Proc. Natl. Acad. Sci. USA, 90:5728). Targeted delivery of
immunomodulatory nucleic acid molecules can also be achieved by
conjugation of the ISS to the surface of viral and non-viral
recombinant expression vectors, to an antigen or other ligand, to a
monoclonal antibody or to any molecule which has the desired
binding specificity.
[0114] Additional Formulation Components
[0115] In addition to immunomodulatory nucleic acid molecules, the
formulations suitable for treatment or prevention of intracellular
pathogen infections according to the present invention can comprise
active or inactive components in lieu of or in addition to the
components described above. For example, the formulation may
comprise anti-pathogenic agents (e.g., antibiotics), particularly
where the ISS is administered for treatment of an active infection.
In one embodiment, the immunomodulatory nucleic acid molecule is
administered with a relevant antigen to further enhance the
subject's immune response against one or more species of
intracellular pathogen. In another embodiment, the immunomodulatory
nucleic acid molecule is administered with one or more
mycobacterial antigens. Mycobacterial antigens of interest may
include, but are not necessarily limited to, the 65 kDa antigen and
antigen 85B of M. avium (Velaz-Faircloth, et al. (1999) Infect.
Immun. 67:4243-4250); the antigen 85B, ESAT-6 and MPT64 of M.
tuberculosis (Kamath, et al. (1999) Infect. Immun. 67:1702-1707),
and M. tuberculosis hsp-65 (Bonato, et al. (1998) Infect. Immun.
66:169-175).
[0116] Kits
[0117] The present invention also provides kits for use in the
methods described herein. Such kits may include any or all of the
following: 1) ISS; 2) a pharmaceutically acceptable carrier (which
may be pre-mixed with the ISS) or suspension base for
reconstituting lyophilized ISS; 3) additional medicaments; 4) a
sterile vial for each ISS and additional medicament, or a single
vial for mixtures thereof; 5) device(s) for use in delivering ISS
to a host; 6) assay reagents for detecting indicia that the desired
immunomodulatory effects have been accomplished in the subject to
which the ISS has been administered and a suitable assay
device.
[0118] Intracellular Pathogen Infections Amenable to Treatment
[0119] The methods and compositions described herein can be used in
the treatment or prevention of any of a variety of infections by
intracellular pathogens (e.g., viruses, bacteria, protozoa, fungi,
and intracellular parasites) in a variety of subjects susceptible
to or having such infections. In one embodiment, the intracellular
pathogen infection is a mycobacterial infection. Of particular
interest is the treatment and/or prevention of infection or disease
by M tuberculosis, M. avium (or M. avium-intracellulare), M. leprae
(particularly M. leprae infection leading to tuberculoid leprosy),
M. kansasii, M. fortuitum, M. chelonae, and M. absecessus. While
treatment of humans is of particular interest, the methods of the
invention can also be used to prevent intracellular pathogen
infection or disease in non-human subjects. For example, M. avium
causes lymphadenitis in slaughter pigs; M. paratuberculosis
infection causes paratuberculosis, a tuberculosis-like disease that
can result in great production losses in cattle, sheep and goats;
and M. bovis is carried by cattle and can cause a tuberculin-like
infection in humans.
[0120] Immunomodulatory nucleic acid molecules can be administered
prophylactically or following onset of disease. Prophylactic
therapy can involve administration of immunomodulatory nucleic acid
molecules prior to exposure to intracellular pathogen, or can be
after exposure, but prior to establishment of infection or disease
(e.g., the subject may be colonized by intracellular pathogen, but
not exhibit or yet exhibit symptoms associated with disease caused
by the intracellular pathogen due to the subject being a carrier or
having been exposed to a sub-infectious dose).
[0121] The methods and compositions of the invention may be
particularly advantageous in the treatment of infection by
drug-resistant strains of intracellular pathogen, as well as
treatment of intracellular pathogen infections in immunocompromised
hosts.
EXAMPLES
[0122] The following examples are put forth so as to provide those
of ordinary skill in the art with a complete disclosure and
description of how to make and use the present invention, and are
not intended to limit the scope of what the inventors regard as
their invention nor are they intended to represent that the
experiments below are all or the only experiments performed.
Efforts have been made to ensure accuracy with respect to numbers
used (e.g., amounts, temperature, etc.) but some experimental
errors and deviations should be accounted for. Unless indicated
otherwise, parts are parts by weight, molecular weight is weight
average molecular weight, temperature is in degrees Centigrade, and
pressure is at or near atmospheric.
[0123] Methods and Materials
[0124] The following procedures are used in the Examples described
in detail below. Although some of the methods described below are
in common use, the specific protocol used in the Examples below is
described in detail where alternative protocols are often employed.
Basic procedures such as DNA digestion by restriction enzymes and
ligation are not described, as such are well within the skill of
the ordinarily skilled artisan and, in some instances, are carried
out according to the enzyme or kit manufacturer's instructions.
[0125] Mice. Female C57B1/6 mice (7 to 8 week-old) were purchased
from The Jackson Laboratory (Bar Harbor, Me.) and from Charles
River Laboratories, Inc. (Wilmington, M. AVIUM). Female 129/SvEv
mice were purchased from Taconic Laboratories, Germantown, N.Y. The
inducible nitric oxide synthetase (iNOS).sup.-/-, IL-12
p40.sup.-/-, TNF-.alpha..sup.-/-, and NADPH oxidase
(gp91phox).sup.-/- knockout mice are on the C57B1/6 background, and
were purchased from The Jackson Laboratory. IFN-.alpha./.beta.
receptor (IFN-.alpha./.beta.R).sup.-/- and IFN-.gamma. receptor
(IFN-.gamma.R).sup.-/- (129/EvSv background) knockout mice were
obtained from B & K Universal Ltd. (East Yorkshire, United
Kingdom).
[0126] Reagents and cytokines. Endotoxin-free (<1 ng/mg DNA),
phosphorothioate single-stranded oligodeoxynucleotides were
obtained from Trilink Biotechnologies, San Diego, Calif. The
sequence of the ISS was 5'-TGACTGTGAACGTTCGAGATGA-3' (SEQ ID NO:
1). The sequence of the mutated-ODN (M-ODN) was
5'-TGACTGTGAAGGTTAGAGATGA-3' (SEQ ID NO:3). The underlined bases
indicate the CpG motif of the polynucleotide or its corresponding 2
base alteration.
[0127] Unless otherwise noted, 10 .mu.g/ml ISS or M-ODN was used.
L-tryptophan (L-try) was obtained from Gibco BRL (Grand Island,
N.Y.) and DMEM was supplemented with L-try for a final
concentration of 66 .mu.g/ml. 1-methyl-DL-tryptophan (M-try) was
purchased from Aldrich Chemicals (Milwaukee, Wis.). Anti-CD3,
anti-CD28, anti-CD4, and anti-CD8 monoclonal antibodies as well as
monensin and murine recombinant IFN-.gamma. were purchased from BD
Pharmingen (San Diego, Calif.). Abbott Laboratories (Abbott Park,
Ill.) kindly provided Clarithromycin (CLA).
[0128] Culture of M. avium. A previously studied M. avium strain 13
(Hayashi, et al. (1999) Infect. Immun. 67:3558-3565; Meylan, et al.
(1990) Infect. Immun. 58:2564-2568), isolated from an AIDS patient
at UCSD, San Diego, Calif., was used in all experiments. The
organism was cultured on Middlebrook 7H 11 agar (Difco
Laboratories, Detroit, Mich.) with OADC enrichment at 37.degree. C.
in the presence of 5% CO.sub.2 for two weeks. Transparent colonies
were selectively picked and further cultured on Middlebrook 7H 11
plates for two more weeks. The resulting colonies, which were
predominantly transparent (>90%), were then collected and washed
two times with phosphate-buffered saline (PBS). The bacteria were
finally resuspended in Middlebrook 7H9 broth (Difco Laboratories)
and the OD.sub.600 of the suspension was adjusted to 0.15-0.2. The
suspension was aliquoted and stored at -70.degree. C. until use.
The number of organisms/ml of this suspension was determined by the
colony forming unit (CFU) assay.
[0129] CFU assay. The number of CFU in a given sample was
determined by colony counting as described previously (Ogata, et
al. (1992) Infect. Immun. 60:4720-4725). Serial 10-fold dilutions
of total cell lysates or tissue homogenates were performed in PBS.
10 .mu.l of each dilution were plated on Middlebrook 7H 11 plates
supplemented with OADC enrichment. The plates were incubated up to
14 days at 37.degree. C. The number of colonies was counted every
alternate day from day 10 onwards until no new colonies appeared.
This yielded the number of CFU/10 .mu.l. The number of CFU in each
well was then calculated.
[0130] Isolation of human monocytes. Monocytes were isolated from
normal human buffy coats obtained from the San Diego Blood Bank by
Ficoll-Hypaque and Percoll gradient centrifugation (Hayashi, et al.
(1997) Infect. Immun. 65:5262-5271). Purity of the monocytes by
this method was greater than 70%. The monocytes thus isolated were
cultured for five to seven days in Iscove's Modified Dulbecco's
Medium (BioWhittaker, Walkersville, Md.) supplemented with 10%
normal human serum (Irvine Scientific, Santa Ana, Calif.), 2 mM
L-glutamine and 50 units/ml penicillin-streptomycin in Teflon
beakers to yield human monocyte-derived macrophages (hMDM). These
hMDM were further enriched by adherence to the wells of tissue
culture plates before use in experiments. Purity of hMDM after the
second adherence assessed by esterase staining was >95%.
Viability determined by trypan blue exclusion was >97%.
[0131] Preparation of murine macrophages. Mouse bone marrow-derived
macrophages (mBMDM) were prepared from mouse bone marrow using
L-cell conditioned media, as described in Martin-Orozco, et al.
(1999) Immunology 11: 1111-1118.
[0132] Effect of ISS on intracellular growth of M. avium in vitro.
hMDM (6.times.10.sup.4) were adhered to the wells of 96-well tissue
culture plates for two hours and non-adherent cells were removed by
washing with warm RPMI-1640. Adherent cells were treated with ISS
at 3, 10, or 30 .mu.g/ml for 72 h before infection with M. avium.
Cells treated with M-ODN at 10 .mu.g/ml or with media alone served
as controls. After 72 h, the cells were washed two times and
infected with M. avium in RPMI-1640 supplemented with 5%
heat-inactivated fetal bovine serum (FBS, Irvine Scientific) at a
cell:bacteria ratio of 1:5-1: 10. On days 1, 3 and 7 after
infection, the total number of colony forming units (CFU) in each
well was determined. The supernatant was collected and set aside
and the adherent cells were lysed. To account for all the
mycobacteria in each well, corresponding lysates and supernatants
were combined and used to determine the number of CFU. Experiments
were done in triplicate and results were expressed as mean.+-.SD of
CFU per well.
[0133] Alternatively, 5.times.10.sup.4 mBMDM or hMDM was treated
with ISS for 3 days before infection. Macrophages treated with
M-ODN or with media alone served as controls. After 3 days, the
cells were infected for 2 hrs with M. avium at a
macrophage:bacteria ratio of 2:1 for mBMDM or of 1:10 for hMDM, and
subsequently cultured in fresh media without antibiotics. To
examine attachment and/or invasion of M. avium, the macrophages
were lysed immediately after washing, and the number of bacteria
were enumerated by the CFU assay. Intracellular growth of M. avium
was determined on days 1, 3, and 7 after infection. To account for
all the mycobacteria in each group, corresponding lysates were
combined and then the number of CFU was determined. To examine the
efficacy of anti-mycobacterial treatments, CFU recovered from cells
treated with medium alone were considered as 100% growth.
[0134] To determine whether treatment with ISS after infection
alters M. avium growth, adherent cells were first infected with M.
avium for 2 hrs and then these cells were cultured with fresh media
containing ISS. Infected cells treated with M-ODN or medium alone
served as controls. At day 7, intracellular growth of M. avium was
assessed by CFU assay.
[0135] Effect of ISS on growth of M. avium in vivo in mice. Three
days before infection, the experimental mice (n=5) were injected
intradermally with ISS (100 .mu.g/mouse in 50 .mu.l). The control
mice (n=5) received PBS (50 I11/mouse). All mice were infected
intravenously with M. avium (1.times.10.sup.6/mouse or
1.times.10.sup.7/mouse). At 2, 4, and 6 weeks after infection, mice
were sacrificed and the spleen, liver, and lungs from each mouse
were collected and weighed. Blood was collected by cardiac puncture
and used in the ELISA studies described below. A section of each
organ was minced and homogenized for 30 s with 0.25% SDS in PBS (1
ml/100 mg of tissue). The number of CFU in the tissue homogenates
was determined by the CFU assay and the results were expressed as
CFU/organ. All procedures were performed under a biosafety cabinet
in a biosafety level 2 facility.
[0136] To study the effect of ISS when combined with CLA in vivo,
25 mice were injected with M. avium (1.times.10.sup.7/mouse). One
week after infection, treatment with either ISS or M-ODN and CLA
was initiated. The mice were divided into 5 treatment groups (n=5
per group): group 1, no treatment; group 2, ISS alone; group 3, CLA
alone; group 4, CLA and ISS; and group 5, CLA and M-ODN. CLA (200
mg/kg) was administered intraperitoneally three times a week for
four weeks (Doherty, et al. (1998) J. Immunol. 160:5428-5435) and
bacterial growth in the spleen, liver and lungs was determined.
[0137] Intracellular IFN-.gamma. staining and detection of secreted
IFN-.gamma. by ELISA. Mice were injected intradermally (i.d.) with
ISS (50 .mu.g/mouse). The control mice received M-ODN (50
.mu.g/mouse) or PBS (50 .mu.l/mouse). All mice were infected with
1.times.10.sup.7 M. avium. Three weeks after infection, the mice
were sacrificed and splenocytes from mice receiving the same
treatment were pooled. Intracellular cytokine staining was
performed using the Cytofix/Cytoperm kit (Pharmingen) according to
the manufacturer's instructions. Briefly, the splenocytes were
stimulated with anti-CD3 and anti-CD28 activating antibodies in the
presence of monensin to allow intracellular IFN-.gamma. to
accumulate for 6 hrs. Next, surface CD4 and CD8 were stained for,
the cells were fixed, and the plasma membranes were permeabilized,
allowing for intracellular staining with anti-IFN-.gamma.. The
cells were analyzed on a FACSCalibur flow cytometer (Becton
Dickenson). To study IFN-.gamma. production, splenocytes were
incubated with anti-CD3 and anti-CD28 antibodies in vitro for 24
hrs, and these supernatants were assayed for the presence of
IFN-.gamma. by sandwich ELISA (Martin-Orozco, et al. (1999) Int.
Immun. 11:1111-1118).
[0138] RNA extraction, RT-PCR, and IDO activity assay.
1-4.times.10.sup.6 mBMDM were treated with ISS or M-ODN. After 3
days, the cells were infected with M. avium for 2 hrs. At 2, 24,
and 48 hrs after infection, the M. avium-infected macrophages were
lysed and total RNA was isolated using the Trizol Reagent (Gibco
BRL). The induction of IDO gene transcription was measured by
semi-quantitative RT-PCR. First-strand cDNA preparation and PCR
amplification was carried out using the SuperScript
Pre-amplification System (Gibco BRL) and AdvanTaq Plus DNA
polymerase (Clontech, San Francisco, Calif.), respectively. PCR
products were visualized by electrophoresis on 2% agarose gels. The
primer sequences used were as follows:
3 IDO: 5'-TTATGCAGACTGTGTCCTGGCAAA-3' and
5'-TTTCCAGCCAGACAGATATATGCG-3', G3PDH: 5'-ACCACAGTCCATGCCATCAC-3'
and 5'-TCCACCACCCTGTTGCTGTA- -3'
[0139] IFN-.gamma. and IL-12 measurement in the serum of M.
avium-infected mice. Serum obtained from M. avium-infected mice
that received ISS or PBS was assayed for IFN-.gamma. and IL-12 by
ELISA using mouse IFN-.gamma. and IL-12 (p70) ELISA kits (Endogen,
Inc. Woburn, M. AVIUM), respectively, and following the
manufacturer's instructions.
[0140] Histologic examination. Sections of the spleen and liver
collected from the experimental and control M. avium-infected mice
at 2, 4, and 6 weeks post-infection, were fixed overnight in 10%
buffered formalin at room temperature, and embedded in paraffin.
The paraffin-embedded tissue was further sectioned (5 .mu.m
thickness), stained with hematoxylin-eosin and observed under an
Olympus microscope. At least three sections from each organ of each
of the experimental and control mice were evaluated and
representative fields were viewed at 100.times..
[0141] Statistical analysis. Results were expressed as mean.+-.SD.
Statistical differences were determined using the Student's t test
(two-tailed distribution). A P value at or below 0.05 was
considered to be statistically significant.
Example 1
In Vitro Effect of ISS on the Growth of M. avium in Human MDM
[0142] To examine whether ISS has a direct effect on the growth of
M. avium in human monocyte-derived macrophages (hMDM), hMDM were
prepared as described above (6.times.10.sup.4 hMDM/well) and
pretreated with ISS or M-ODN for 72 h before infection and then
infected with M. avium. The number of CFU within the cells was
determined on days 1, 3 and 7 post-infection.
[0143] On day 7, maximum inhibition of intracellular growth of M.
avium was observed in the case of hMDM pretreated with 3 .mu.g/ml
of ISS (91.3.+-.1.7%) in comparison with HMDM treated with medium
alone or those treated with M-ODN (p<0.001) (FIG. 1). There was
no further increase in growth inhibition at the higher
concentrations of ISS tested. These results demonstrate that ISS
can directly stimulate macrophages to restrict the intracellular
growth of M. avium.
[0144] In summary, these data show that pretreatment of hMDM with
ISS significantly inhibited the intracellular growth of M. avium
for up to 7 days, demonstrating that ISS may directly activate
macrophages to kill M. avium.
Example 2
Effect of Treatment with ISS Upon Infected hMDM
[0145] To study the effect of ISS upon growth of M. avium in an
on-going infection of hMDM, hMDM were infected as described above
(6.times.10.sup.4 hMDM/well) and incubated with ISS (10 mg/ml)
either immediately after infection, or one day after infection. In
some wells hMDM were pretreated with ISS (10 mg/ml) three days
before infection and were then infected with M. avium as described
above. CFU of these wells was determined at day 7. Experiments were
done in triplicate and results were expressed as mean.+-.SD of CFU
per well.
[0146] Pretreatment of ISS three days before infection (-3 days)
inhibited intracellular growth of M. avium 51.+-.4% compared to
medium alone as the control (FIG. 2). Treatment with ISS
immediately after infection (0 day) and one day after infection (+1
day) inhibited growth of M. avium 53.+-.18% and 36+16%,
respectively. These data indicate that treatment with ISS after
infection can also activate hMDM to inhibit M. avium growth as well
as pretreatment with ISS.
Example 3
Effect of ISS Upon M. avium Infection in the Presence of
Antibiotics
[0147] In order to assess whether ISS would work effectively with
other anti-mycobacterial agents, the effect of ISS and the
antibiotic clarithromycin (ZITHROMAX.RTM., Pfizer Labs, New York,
N.Y.) were coadministered to M. avium-infected hMDM and
intracellular growth of M. avium was evaluated. M. avium-infected
hMDM were prepared as described above (6.times.10.sup.4 hMDM/well),
and then incubated with ISS (10 .mu.g/ml) in the presence or
absence of 1 .mu.g/ml, 4 .mu.g/ml, or 20 .mu.g/ml clarithromycin,
an antibiotic used to treat M. avium infection. CFU was determined
on days 0 and 7 after infection. The experiment was done in
triplicate and results expressed as mean.+-.SD of CFU per well.
[0148] On day 7, ISS alone inhibited intracellular growth of M.
avium by 38.+-.7% (p=0.05) (FIG. 3). ISS further enhanced the
anti-mycobacterial effect of 1 .mu.g/ml and 4 .mu.g/ml
clarithromycin by 89.+-.5% (p<0.001) and 63.+-.12% (p=0.001),
respectively, compared to antibiotic alone. These data show that
ISS and clarithromycin had a synergistic effect in inhibition of M.
avium replication. In another experiment, hMDM (5.times.10.sup.4
hMDM/well) were treated with ISS or M-ODN (3, 10, and 30 .mu.g/ml)
for 3 days and then infected them with M. avium. There was maximal
inhibition of M. avium growth at 3 .mu.g/ml of ISS (FIG. 4A) with
no further increase in inhibition at the higher concentrations
(data not shown). At 7 days post-infection, treatment with ISS was
found to have inhibited intracellular growth of M. avium by 91%
(FIG. 4A, p<0.001). No changes in cell viability in the various
groups was observed. To study the therapeutic effects of ISS on
established M. avium infection, infected hMDM were treated with ISS
(10 .mu.g/ml) for 7 days. Treatment with ISS significantly
decreased the intracellular growth of M. avium in hMDM by 53%
(p<0.05) (FIG. 4B). When infected cells were treated with ISS
together with CLA (0.5 .mu.g/ml), M. avium growth was further
inhibited up to 99% (p<0.01), compared to medium alone (FIG.
4B).
Example 4
ISS is a Potent Adjunct to Anti-Mycobacterial Therapy with CLA
[0149] mBMDM (5.times.10.sup.4 mBMDM/well) was first infected with
M. avium and then these cells were treated with CLA (0.1 .mu.g/ml)
in the presence or absence of ISS (10 pg/ml) or M-ODN (10 .mu.g/ml)
and M. avium growth in vitro 7 days after infection was determined.
ISS and CLA (0.1 .mu.g/ml), when used individually, reduced
bacterial growth in mBMDM by 68% and 84%, respectively (p<0.01,
FIG. 5A). When ISS was used together with CLA, bacterial counts
were further reduced (95%, p<0.01) compared to medium alone
(FIG. 5A).
[0150] C57B1/6 mice were infected intravenously with M. avium
(10.sup.7 CFU) and were treated with a combination of ISS-ODN (50
.mu.g/mouse) and/or CLA (200 mg/kg) one week after infection. Mice
were sacrificed 5 weeks after infection and CFU in the spleen,
liver, and lungs were counted. Treatment with CLA alone decreased
bacterial growth in the spleen (4 log reduction, FIG. 5B), liver (4
log reduction, FIG. 5D) and lungs (1.5 log reduction, FIG. 5C). In
this therapeutic model, ISS alone did not inhibit the growth of M.
avium. However, when ISS was combined with CLA, there was a further
reduction of bacterial counts in the spleen (<1 log reduction,
p<0.01, FIG. 5B) and especially in the lungs (3 log reduction,
p<0.01, FIGS. 5B-5D). These findings show that ISS can enhance
the therapeutic efficacy of CLA in the setting of established M.
avium infection.
Example 5
In Vivo Effect of ISS on M. avium Infection in Mice
[0151] The ability of ISS to elicit a protective immune response
against mycobacterial infection was tested in an animal model of
disseminated mycobacterial infection. C57B1/6 mice were pretreated
intradermally with ISS and subsequently infected with 10.sup.6 or
10.sup.7 organisms/mouse as described in the Materials and Methods
above.
[0152] a) Bacterial Load
[0153] At 2, 4 and 6 weeks after infection, the spleen, liver, and
lungs were collected from the M. avium-infected mice (10.sup.6
organisms/mouse), homogenized and used to determine the number of
CFU as described in Materials and Methods above.
[0154] At week 2, the lungs of M. avium-infected mice pretreated
with ISS were found to contain a significantly lower number of
viable bacteria compared to those of infected mice which received
PBS instead of ISS (p<0.05). In addition, M. avium-infected mice
pretreated with ISS were found to have an almost two logs lower
number of bacteria in the spleen (p<0.05) compared to the
PBS-pretreated mice (FIG. 6). These effects were maximal at 4
weeks. At week 6, CFU in the spleen of mice treated with ISS
equaled that observed in the control mice treated with PBS.
Surprisingly, at week 6 the bacterial load in the lungs of
ISS-treated mice exceeded that found in the lungs of control mice
(FIG. 6). This observation suggests that ISS alone does not
eradicate the mycobacterial infection under the conditions
described.
[0155] There was no significant difference in the bacterial loads
in the liver of mice pretreated with ISS compared to those
recovered from mice pretreated with PBS at any of the time points
(data not shown). Thus, a single injection of ISS significantly
reduced the mycobacterial growth in the spleen and the lungs, but
not in the liver in M. avium-infected mice. This protective effect
was found to persist for up to four weeks after administration of
ISS. These data demonstrate that ISS by itself can induce strong
protective immunity against mycobacterial infections even in the
absence of specific DNA sequences which code for mycobacterial
antigens.
[0156] In another experiment, mice were treated with ISS and
infected intravenously (i.v.) three days later with M. avium
(10.sup.7 organisms/mouse). At 2, 4, and 6 weeks after infection,
the number of CFU in the spleen, lungs, and liver were determined.
Four weeks after infection, CFU in the spleen and lungs were
similar in the mice treated with M-ODN and control (PBS) mice, but
were significantly higher than in the ISS-treated mice (by 2 logs
and 1 log in spleen and lungs, respectively).
[0157] At week 2, the lungs of M. avium-infected mice treated with
ISS prior to infection contained a significantly lower number of
viable bacteria compared to control PBS-treated mice (p<0.05)
(FIG. 7B). In addition, mice treated with ISS prior to M. avium
infection had nearly two logs less bacteria in the spleen at 4
weeks (p<0.05) compared to the PBS-treated mice (FIG. 7A). By 6
weeks, however, splenic CFU counts were similar in control and ISS
groups. There was no significant difference in the mycobacterial
loads in the liver of mice treated with ISS prior to infection
compared to PBS-treated mice at any of these time points (FIG. 7C).
Thus, a single injection of ISS significantly reduced the
mycobacterial growth in the spleen and lungs, but not in the liver
of M. avium-infected mice. This protective effect was transient and
was most apparent at 2 and 4 weeks after a single administration of
ISS.
[0158] b) Serum IFN-.gamma. and IL-12 Levels.
[0159] To determine whether production of IFN-.gamma. and IL-12
could be responsible for the protective effect exerted by ISS,
serum was collected from the ISS-treated or PBS-treated M.
avium-infected mice (10.sup.6 organisms/mouse) at 2, 4, and 6 weeks
after infection. Serum IFN-.gamma. levels of mice infected with M.
avium was found to be significantly higher than that of uninfected
mice throughout the experiment (p<0.05) (FIG. 8). However, there
were no significant differences in the serum IFN-.gamma. levels of
ISS-pretreated mice compared to PBS-pretreated mice. Serum IL-12
levels were found to be less than that detectable by the ELISA
(<5 pg/ml).
[0160] In other experiments not described here, the serum level of
IFN-.gamma. and IL-12 after administration of ISS peaks at day 1,
after which levels begin to decline and attain basal levels within
3 weeks post injection (data not shown) (see, e.g., Kobayashi et
al. (1999) Cell. Immunol. 198:69-25).
[0161] These data indicate that there is no significant difference
in serum IFN-.gamma. levels between ISS-treated and PBS-treated
infected mice. This could be due to the fact that induction of
IFN-.gamma. production is an early event during the course of M.
avium infection. Our earliest blood samples for IFN-.gamma. assay
were collected 2 weeks after infection, by which time the
IFN-.gamma. levels may have returned to the basal level.
Alternatively, M. avium may induce IFN-7 production as efficiently
as ISS so no differences would be observed. Serum IL-12 (p70) was
found to be undetectable at all the time points of the experiment
(2, 4 and 6 weeks). In studies by other investigators, total IL-12
(p4.sup.0 and p70) was measured, whereas in our study, only
biological-active IL-12 p70 was measured, which may explain the
disparity in observations.
[0162] c) Histology.
[0163] Tissue sections from the spleen of M. avium-infected mice
treated with ISS, PBS or uninfected mice were fixed and stained
with hematoxylin-eosin as described in the Materials and Methods
above. At week 4, the white pulp in the spleen from M.
avium-infected mice treated with PBS was disrupted with the
formation of several granulomas, while the white pulp in the spleen
of the uninfected mice was intact. Sections of the spleen from the
ISS-treated mice also revealed the presence of granulomas, although
they were notably smaller in size and surrounded by mononuclear
cells in contrast to the spleens from infected mice treated with
PBS.
[0164] The red pulp in spleens of ISS-treated mice appeared to
contain increased hematopoietic cells. However, at week 6, the
granulomas in the spleens from ISS-treated, M. avium-infected mice
were not significantly different from those of PBS-treated, M.
avium-infected mice correlating well with the CFU data and the loss
of effect of ISS observed at this time point (presented above).
[0165] Overall, ISS appears to cause a delay in the formation of
granulomas, which may be associated with the presence of increased
numbers of mononuclear and hematopoietic cells in the spleen. The
livers of the M. avium-infected mice showed a significant number of
granulomas at weeks 4 and 6, while the livers from uninfected mice
did not show any granulomas, as expected. However, there were no
significant histopathological differences in the livers recovered
from the ISS-treated, M. avium-infected mice compared to those
recovered from PBS-treated, M. avium-infected mice (data not
shown).
[0166] d) Summary
[0167] These data show that a significant inhibitory effect by ISS
against M. avium growth was seen in the spleen and the lungs, but
not significantly in the liver. Histopathology studies showed that
the spleen of ISS treated, M. avium-infected mice contained
significantly increased numbers of mononuclear cells compared to
the spleen of the PBS-treated, M. avium-infected control mice. No
significant histopathological differences were observed between the
livers recovered from ISS-treated and PBS-treated mice.
Example 6
In Vivo Effect of ISS on the Growth of M. avium in Mouse BMDM
[0168] The following studies were performed to address whether
ISS-induced activation of macrophages in vitro inhibits
intracellular growth of M. avium.
[0169] a) Treatment Prior to Infection.
[0170] To examine whether treatment with ISS can stimulate
macrophages to inhibit the growth of M. avium, mBMDM
(5.times.10.sup.4 mBMDM/well) was first treated with ISS or M-ODN
for 72 hrs and then infected with M. avium. Then, cellular CFU was
counted on days 1, 3, and 7 post-infection (FIG. 9A). By day 7,
treatment with ISS inhibited intracellular growth of M. avium in
mBMDM by 80% (p<0.001). Since viability of macrophages can
affect M. avium growth, the viability of macrophages was assessed
by trypan-blue exclusion. At day 7 after infection, mBMDM treated
with ISS, M-ODN or medium alone were all >90% viable.
[0171] ISS activate macrophages and induce the expression of
surface adhesion molecules such as ICAM-1 (Martin-Orozco, et al.
(1999) Int. Immun. 11: 1111-1118). These molecules may affect the
attachment of M. avium or its invasion into mouse bone
marrow-derived macrophages (mBMDM). In order to determine whether
the ability of ISS to inhibit M. avium growth is due to alterations
in susceptibility to M. avium invasion, the ability of ISS to
influence the number of bacteria that attached to and invaded
macrophages after incubation with M. avium was examined. CFU
recovered immediately from cells treated with ISS before infection
were not significantly different than CFU recovered from cells
treated with mutated (M)-ODN or with medium alone.
[0172] b) Treatment After Infection.
[0173] To study the therapeutic anti-mycobacterial effect of ISS,
infected mBMDM were treated with ISS for 7 days after infection,
starting two hours after time of infection. Treatment with ISS
significantly decreased the intracellular growth of M. avium in
mBMDM by 68% (p<0.05), compared to CFU in infected cells treated
with M-ODN or medium alone (FIG. 9B).
Example 7
ISS Protection In Vivo is not Significantly Mediated Through
Augmentation of the T Cell Response.
[0174] The observations that ISS protects isolated macrophages in
vitro (FIG. 9) and that the protective effect observed in
ISS-treated mice is transient (FIGS. 6 and 7) suggest a T-cell
independent mechanism of protection via innate immunity. To further
investigate the potential role of adaptive immunity in this model
of ISS-mediated protection against M. avium, mice were treated with
ISS or M-ODN (50 .mu.g/mouse), infected with 10.sup.7
organisms/mouse, and then their T-cell response was evaluated. The
mice were sacrificed at three weeks post-infection and the
splenocytes were re-stimulated with anti-CD3 and anti-CD28
antibodies to amplify the response from pre-existing memory and
activated T cells. T cells were then examined for their production
of IFN-.gamma. by two complementary methods. FACS-based
intracellular cytokine staining was used to determine the
frequencies of IFN-.gamma. producing CD4.sup.+ (FIG. 10A) and
CD8.sup.+ (FIG. 10B) T cells, and ELISA was used to determine the
total quantity of IFN-.gamma. secreted by CD4.sup.+ and CD8.sup.+ T
cells combined (FIG. 10C). There was a dramatic increase in the
IFN-.gamma. response of the CD4.sup.+ T cells and in the total
IFN-.gamma. produced in the infected vs. uninfected animals,
demonstrating that the observed Th1 response is infection-specific.
However, treatment of M. avium-infected animals with ISS did not
further increase the frequency of infection-specific IFN-.gamma.
positive CD4.sup.+ or CD8.sup.+ T cells nor did it increase the
secretion of total infection-specific IFN-.gamma.. Taken together,
these data suggest that the mechanism of protection by ISS of M.
avium-infected animals does not involve enhancement of the
anti-mycobacterial T-cell response.
Example 8
ISS Inhibition of M. avium Growth in Macrophages is Independent of
iNOS NAPDH Oxidase, IL-12, TNF-.alpha., IFN-.alpha./.beta., and
IFN-.gamma..
[0175] To further investigate the mechanisms of the
anti-mycobacterial effects of ISS, mice with targeted disruptions
of genes known to play roles in M. avium infection were used.
Oxygen radicals generated by NADPH oxidase and induction of nitric
oxide (NO) by iNOS result in anti-microbial activity against many
microorganisms (Miller, et al. (1997) Clin. Microbiol. Rev.
10:1-18; Fang (1997) J. Clin. Invest. 99:2818-2825). IL-12,
TNF-.alpha., and IFN-.gamma. play important roles in the clearance
of M. avium (Kobayashi, et al. (1995) Antimicrob. Agents Chemother.
39:1369-1371; Doherty, et al. (1998) J. Immunol. 160:5428-5435;
Appelberg, et al. (1995) Clin. Exp. Immunol. 101:308-313).
Furthermore, macrophages produce IL-12, TNF-.alpha.,
IFN-.alpha./.beta., and IFN-.gamma. in response to ISS treatment
(Klinman, et al. (1996) Proc. Natl. Acad. Sci. U S A. 93:2879-2883;
Roman, et al. (1997) Nat. Med. 3:849-854).
[0176] To study the role of these molecules in the
anti-mycobacterial effect of ISS, mBMDM from NADPH oxidase.sup.-/-,
iNOS.sup.-/-, TNF-.alpha..sup.-/-, IL-12p40.sup.-/-,
IFN-.alpha./.beta.R.sup.-/- and IFN-.gamma.R-.sup.-/- mice were
treated with ISS for 3 days and then infected with M. avium. ISS
inhibited the intracellular growth of M. avium in MBMDM from these
knockout mice by 60-85% (p<0.05), similar to wild-type mice
(Table 1). These results indicate that these gene products (e.g.,
nitrogen intermediates, oxygen radicals, TNF-.alpha. etc.) are not
central to the anti-mycobacterial effect induced by ISS in
vitro.
4TABLE 1 Effect of ISS on M. avium growth in mBMDM from mice with
targeted disruption of genes known to play a protective role
against M. avium infection. % of CFU.sup.a mBMDM were treated with
Mouse Strain Untreated M-ODN ISS Wild type C57B1/6 100 117.2 .+-.
18.5 18.2 .+-. 7.3.sup.b Wild type 129S6/SvEV 100 110.0 .+-. 15.9
17.0 .+-. 4.0.sup.b INOS.sup.-/- C57B1/6 100 105.0 .+-. 13.0 37.3
.+-. 4.6.sup.b NADPH C57B1/6 100 107.0 .+-. 15.5 11.4 .+-.
1.5.sup.b oxidase.sup.-/- (gp91 phox.sup.-/-) TNF-.alpha..sup.-/-
C57B1/6 100 120.0 .+-. 20.0 24.0 .+-. 6.0.sup.b IL-12 p40.sup.-/-
C57B1/6 100 117.6 .+-. 9.2 26.4 .+-. 10.1.sup.b
IFN-.alpha.R.sup.-/- 129S6/SvEv 100 106.9 .+-. 11.9 10.9 .+-.
01.7.sup.b IFN-.gamma.R.sup.-/- 129S6/SvEv 100 108.1 .+-. 10.8 7.6
.+-. 01.3.sup.b .sup.amBMDM were treated with M-ODN or ISS (10
.mu.g/ml) for 72 h prior to infection and then infected with M.
avium. mBMDM treated with medium alone served as control. On day 7,
M. avium growth was assessed by CFU assay. For comparison purposes,
results are presented as % CFU compared to mBMDM treated with
medium alone, rather than absolute CFU in order to normalize for
strain variation (i.e. C57B1/6 vs. 129S6/SvEv). # CFU of cells
treated with medium alone was considered as 100%. Mean and standard
deviations from three independent experiments are shown .sup.bP
< 0.05, as compared to mBMDM treated with medium alone.
Example 9
Induction of Indoleamine 2,3-dioxygenase (IDO) Contributes to the
Anti-Mycobacterial Activity of ISS.
[0177] IDO is the rate-limiting enzyme in the catabolism of
tryptophan, which thereby limits the availability of this important
amino acid to invading pathogens (Daubener, et al. (1999) Adv. Exp.
Med. Biol. 467:517-524). To study the potential role of IDO in the
anti-mycobacterial effect of ISS, the following were assessed: 1)
the induction of IDO activity as measured by semi-quantitative
RT-PCR in vivo and in vitro and 2) the abrogation of the
anti-mycobacterial effect of ISS by addition of excess L-tryptophan
(L-try) or by using a competitive inhibitor for IDO,
1-methyl-DL-tryptophan (M-try).
[0178] When mice were injected (i.v.) with 50 .mu.g ISS, IDO gene
induction in vivo was observed in the lungs and spleen after 16
hrs, but not in the liver (FIG. 11A). Injection of M-ODN did not
result in any detectable induction of IDO. For in vitro studies
mBMDM were treated with ISS for 3 days prior to M. avium infection.
Then, cells were lysed at 4, 8, and 24 hrs after infection, total
RNA was extracted, and semi-quantitative RT-PCR was performed.
Optimal induction of IDO gene transcription was found to require
both treatment with ISS and M. avium infection (FIG. l B).
[0179] In order to further investigate the role of IDO in the
inhibition of M. avium growth, mBMDM were cultured with the IDO
inhibitor M-try (125 .mu.M) or with excess L-try (final
concentration of 66 .mu.g/ml) (Hwu,et al. (2000) J. Immunol.
164:3596-3599; Munn, et al. (1999) J. Exp. Med. 189:1363-1372).
Addition of L-try or M-try alone at these concentrations did not
alter the viability of mBMDM or M. avium growth in these cells.
However, when the M. avium-infected cells were cultured with L-try
or M-try supplemented media, 4-fold reductions in the
anti-mycobacterial ability of ISS treatment (p<0.05) was
observed (FIG. 11C). Taken together, these data show that IDO plays
a major role in the observed anti-mycobacterial properties of
ISS.
[0180] IDO inhibits the growth of a variety of intracellular
organisms such as Toxoplasma gondi (Pfefferkorn, et al. (1984)
Infect. Immun. 44:211-216), Plasmodium berghe in a murine model of
malaria (Sanni, et al. (1998) Am. J. Pathol. 152:611-619),
Chlamydia psittaci (Carlin, et al. (1989) J. Interferon Res.
9:329-337), and Chlamydia trachomatis (Beatty, et al.(1994) Infect.
Immun. 62:3705-3711) by breaking the L-tryptophan required for
their growth down to L-kynurenine. IDO has been described to be the
most effective anti-parasitic mechanism in most human cells
(Daubener, et al. (1999) Med. Micro. Immunol. 187:143-147),
indicating the broad applicability of ISS for treatment of
infection by a wide variety of intracellular pathogens. The
anti-pathogenic effects of immunomodulatory nucleic acids such as
ISS may induce other anti-pathogen pathways in the host in addition
to induction of IDO.
[0181] In summary, this study demonstrates that administration of
ISS enhances resistance against M. avium infection through the
induction of IDO. The ISS itself provides protection against M.
avium. However this effect can be amplified upon co-delivery with
an anti-mycobacterial drug, Clarithromycin. The combined
administration of ISS with other antibiotics or anti-pathogenic
agents provides an alternative therapeutic strategy for
intracellular pathogen infections.
[0182] While the present invention has been described with
reference to the specific embodiments thereof, it should be
understood by those skilled in the art that various changes may be
made and equivalents may be substituted without departing from the
true spirit and scope of the invention. In addition, many
modifications may be made to adapt a particular situation,
material, composition of matter, process, process step or steps, to
the objective, spirit and scope of the present invention. All such
modifications are intended to be within the scope of the claims
appended hereto.
* * * * *