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McBurney SP, Ross TM. Viral sequence diversity: challenges for AIDS vaccine designs. Expert Rev Vaccines 2008; 7:1405-17. [PMID: 18980542 DOI: 10.1586/14760584.7.9.1405] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Among the greatest challenges facing AIDS vaccine development is the intrinsic diversity among circulating populations of HIV-1 in various geographical locations and the need to develop vaccines that can elicit enduring protective immunity to variant HIV-1 strains. While variation is observed in all of the viral proteins, the greatest diversity is localized to the viral envelope glycoproteins, evidently reflecting the predominant role of these proteins in eliciting host immune recognition and responses that result in progressive evolution of the envelope proteins during persistent infection. Interestingly, while envelope glycoprotein variation is widely assumed to be a major obstacle to AIDS vaccine development, there is very little experimental data in animal or human lentivirus systems addressing this critical issue. In this review, the state of vaccine development to address envelope diversity will be presented, focusing on the use of centralized and polyvalent sequence design as mechanisms to elicit broadly reactive immune responses.
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Affiliation(s)
- Sean P McBurney
- University of Pittsburgh, School of Medicine, Center for Vaccine Research, Program in Molecular Virology and Microbiology, Pittsburgh, PA 15261, USA.
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2
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Craigo JK, Durkin S, Sturgeon TJ, Tagmyer T, Cook SJ, Issel CJ, Montelaro RC. Immune suppression of challenged vaccinates as a rigorous assessment of sterile protection by lentiviral vaccines. Vaccine 2006; 25:834-45. [PMID: 17023099 PMCID: PMC1855206 DOI: 10.1016/j.vaccine.2006.09.040] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2006] [Revised: 08/21/2006] [Accepted: 09/07/2006] [Indexed: 01/19/2023]
Abstract
We previously reported that an experimental live-attenuated equine infectious anemia virus (EIAV) vaccine, containing a mutated S2 accessory gene, provided protection from disease and detectable infection after virulent virus (EIAV(PV)) challenge [Li F, Craigo JK, Howe L, Steckbeck JD, Cook S, Issel C, et al. A live-attenuated equine infectious anemia virus proviral vaccine with a modified S2 gene provides protection from detectable infection by intravenous virulent virus challenge of experimentally inoculated horses. J Virol 2003;77(13):7244-53; Craigo JK, Li F, Steckbeck JD, Durkin S, Howe L, Cook SJ, et al. Discerning an effective balance between equine infectious anemia virus attenuation and vaccine efficacy. J Virol 2005;79(5):2666-77]. To determine if attenuated EIAV vaccines actually prevent persistent infection by challenge virus, we employed a 14-day dexamethasone treatment of vaccinated horses post-challenge to suppress host immunity and amplify replication levels of any infecting EIAV. At 2 months post-challenge the horses were all protected from virulent-virus challenge, evidenced by a lack of EIA signs and detectable challenge plasma viral RNA. Upon immune suppression, 6/12 horses displayed clinical EIA. Post-immune suppression characterizations demonstrated that the attenuated vaccine evidently prevented detectable challenge virus infection in 50% of horses. These data highlight the utility of post-challenge immune suppression for evaluating persistent viral vaccine protective efficacy.
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Affiliation(s)
- Jodi K. Craigo
- Department of Molecular Genetics and Biochemistry, University of Kentucky, Lexington, KY 40516
| | - Shannon Durkin
- Department of Molecular Genetics and Biochemistry, University of Kentucky, Lexington, KY 40516
| | - Timothy J. Sturgeon
- Department of Molecular Genetics and Biochemistry, University of Kentucky, Lexington, KY 40516
| | - Tara Tagmyer
- Department of Molecular Genetics and Biochemistry, University of Kentucky, Lexington, KY 40516
| | - Sheila J. Cook
- Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, KY 40516
| | - Charles J. Issel
- Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, KY 40516
| | - Ronald C. Montelaro
- Department of Molecular Genetics and Biochemistry, University of Kentucky, Lexington, KY 40516
- *Corresponding Author: Department of Molecular Genetics and Biochemistry, W1144 Biomedical Science Tower, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, Phone: 412-648-8869, Fax: 412-383-8859,
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Steckbeck JD, Grieser HJ, Sturgeon T, Taber R, Chow A, Bruno J, Murphy-Corb M, Montelaro RC, Cole KS. Dynamic evolution of antibody populations in a rhesus macaque infected with attenuated simian immunodeficiency virus identified by surface plasmon resonance. J Med Primatol 2006; 35:248-60. [PMID: 16872288 PMCID: PMC3361734 DOI: 10.1111/j.1600-0684.2006.00173.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Increasing evidence suggests that an effective AIDS vaccine will need to elicit broadly neutralizing antibody responses. However, the mechanisms of antibody-mediated neutralization have not been defined. Previous studies from our lab have identified significant differences in the rates of antibody binding to trimeric SIV envelope proteins that correlate with neutralization sensitivity. Importantly, these results demonstrate differences in monoclonal antibody (MAb) binding to neutralization-sensitive and neutralization-resistant envelope proteins, suggesting that one mechanism for virus neutralization may be related to the stability of antibody binding. To date, little has been done to evaluate the binding properties of polyclonal serum antibodies elicited by SIV infection or vaccination. METHODS In the current study, we translate these findings with MAbs to study antibody binding properties of polyclonal serum antibody responses generated in rhesus macaques infected with attenuated SIV. Quantitative and qualitative binding properties of well-characterized longitudinal serum samples to trimeric, recombinant SIV gp140 envelope proteins were analyzed using surface plasmon resonance (SPR) technology (Biacore). RESULTS Results from these studies identified two antibody populations in most of the samples analyzed; one antibody population exhibited fast association/dissociation rates (unstable) while the other population demonstrated slower association/dissociation rates (stable). Over time, the percentage of the total binding response of each antibody population evolved, demonstrating a dynamic evolution of the antibody response that was consistent with the maturation of antibody responses defined using our standard panel of serological assays. However, the current studies provided a higher resolution analysis of polyclonal antibody binding properties, particularly with respect to the early time-points post-infection (PI), that is not possible with standard serological assays. More importantly, the increased stability of the antibody population with time PI corresponded with potent neutralization of homologous SIV in vitro. CONCLUSIONS These results suggest that the stability of the antibody-envelope interaction may be an important mechanism of serum antibody virus neutralization. In addition, measurements of the 'apparent' rates of association and dissociation may offer unique numerical descriptors to characterize the level of antibody maturation achieved by candidate vaccine strategies capable of eliciting broadly neutralizing antibody responses.
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Affiliation(s)
- J D Steckbeck
- Department of Medicine, Infectious Diseases Division, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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4
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Singh DK, Liu Z, Sheffer D, Mackay GA, Smith M, Dhillon S, Hegde R, Jia F, Adany I, Narayan O. A noninfectious simian/human immunodeficiency virus DNA vaccine that protects macaques against AIDS. J Virol 2005; 79:3419-28. [PMID: 15731236 PMCID: PMC1075712 DOI: 10.1128/jvi.79.6.3419-3428.2005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Simian/human immunodeficiency virus SHIV(KU2) replicates with extremely high titers in macaques. In order to determine whether the DNA of the viral genome could be used as a vaccine if the DNA were rendered noninfectious, we deleted the reverse transcriptase gene from SHIVKU2 and inserted this DNA (DeltartSHIVKU2) into a plasmid that was then used to test gene expression and immunogenicity. Transfection of Jurkat and human embryonic kidney epithelial (HEK 293) cells with the DNA resulted in production of all of the major viral proteins and their precursors and transient export of a large quantity of the Gag p27 into the supernatant fluid. As expected, no infectious virus was produced in these cultures. Four macaques were injected intradermally with 2 mg of the DNA at 0, 8, and 18 weeks. The animals developed neutralizing antibodies and low enzyme-linked immunospot assay (E-SPOT) titers against SHIVKU2. These four animals and two unvaccinated control animals were then challenged with heterologous SHIV89.6P administered into their rectums. The two control animals developed viral RNA titers exceeding 10(6) copies/ml of plasma, and these titers were accompanied by the loss of CD4+ T cells by 2 weeks after challenge. The two control animals died at weeks 8 and 16, respectively. All four of the immunized animals became infected with the challenge virus but developed lower titers of viral RNA in plasma than the control animals, and the titers decreased over time in three of the four macaques. The fourth animal remained viremic and died at week 47. Whereas the control animals failed to develop E-SPOT responses, all four of the immunized animals developed anamnestic E-SPOT responses after challenge. The animal that died developed the highest E-SPOT response and was the only one that produced neutralizing antibodies against the challenge virus. These results established that noninfectious DNA of pathogenic SHIV could be used as a vaccine to prevent AIDS, even though the immunological assays used did not predict the manner in which the challenge virus would replicate in the vaccinated animals.
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Affiliation(s)
- Dinesh K Singh
- Marion Merrell Dow Laboratory of Viral Pathogenesis, The University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160, USA
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5
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Craigo JK, Li F, Steckbeck JD, Durkin S, Howe L, Cook SJ, Issel C, Montelaro RC. Discerning an effective balance between equine infectious anemia virus attenuation and vaccine efficacy. J Virol 2005; 79:2666-77. [PMID: 15708986 PMCID: PMC548432 DOI: 10.1128/jvi.79.5.2666-2677.2005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Among the diverse experimental vaccines evaluated in various animal lentivirus models, live attenuated vaccines have proven to be the most effective, thus providing an important model for examining critical immune correlates of protective vaccine immunity. We previously reported that an experimental live attenuated vaccine for equine infectious anemia virus (EIAV), based on mutation of the viral S2 accessory gene, elicited protection from detectable infection by virulent virus challenge (F. Li et al., J. Virol. 77:7244-7253, 2003). To better understand the critical components of EIAV vaccine efficacy, we examine here the relationship between the extent of virus attenuation, the maturation of host immune responses, and vaccine efficacy in a comparative study of three related attenuated EIAV proviral vaccine strains: the previously described EIAV(UK)DeltaS2 derived from a virulent proviral clone, EIAV(UK)DeltaS2/DU containing a second gene mutation in the virulent proviral clone, and EIAV(PR)DeltaS2 derived from a reference avirulent proviral clone. Inoculations of parallel groups of eight horses resulted in relatively low levels of viral replication (average of 10(2) to 10(3) RNA copies/ml) and a similar maturation of EIAV envelope-specific antibody responses as determined in quantitative and qualitative serological assays. However, experimental challenge of the experimentally immunized horses by our standard virulent EIAV(PV) strain by using a low-dose multiple exposure protocol (three inoculations with 10 median horse infective doses, administered intravenously) revealed a marked difference in the protective efficacy of the various attenuated proviral vaccine strains that was evidently associated with the extent of vaccine virus attenuation, time of viral challenge, and the apparent maturation of virus-specific immunity.
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Affiliation(s)
- Jodi K Craigo
- Department of Molecular Genetics and Biochemistry, W1144 Biomedical Science Tower, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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6
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Cole KS, Steckbeck JD, Rowles JL, Desrosiers RC, Montelaro RC. Removal of N-linked glycosylation sites in the V1 region of simian immunodeficiency virus gp120 results in redirection of B-cell responses to V3. J Virol 2004; 78:1525-39. [PMID: 14722307 PMCID: PMC321372 DOI: 10.1128/jvi.78.3.1525-1539.2004] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
One mechanism of immune evasion utilized by human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) envelope glycoproteins is the presence of a dense carbohydrate shield. Accumulating evidence from in vitro and in vivo experiments suggests that alterations in N-linked glycosylation of SIV gp120 can enhance host humoral immune responses that may be involved in immune control. The present study was designed to determine the ability of glycosylation mutant viruses to redirect antibody responses to shielded envelope epitopes. The influence of glycosylation on the maturation and specificity of antibody responses elicited by glycosylation mutant viruses containing mutations of specific N-linked sites in and near the V1 and V2 regions of SIVmac239 gp120 was determined. Results from these studies demonstrated a remarkably similar maturation of antibody responses to native, fully glycosylated envelope proteins. However, analyses of antibodies to defined envelope domains revealed that mutation of glycosylation sites in V1 resulted in increased antibody recognition to epitopes in V1. In addition, we demonstrated for the first time that mutation of glycosylation sites in V1 resulted in a redirection of antibody responses to the V3 loop. Taken together, these results demonstrate that N-linked glycosylation is a determinant of SIV envelope B-cell immunogenicity in addition to in vitro antigenicity. In addition, our results demonstrate that the absence of N-linked carbohydrates at specific sites can influence the exposure of epitopes quite distant in the linear sequence.
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Affiliation(s)
- Kelly Stefano Cole
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA.
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7
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Li F, Craigo JK, Howe L, Steckbeck JD, Cook S, Issel C, Montelaro RC. A live attenuated equine infectious anemia virus proviral vaccine with a modified S2 gene provides protection from detectable infection by intravenous virulent virus challenge of experimentally inoculated horses. J Virol 2003; 77:7244-53. [PMID: 12805423 PMCID: PMC164776 DOI: 10.1128/jvi.77.13.7244-7253.2003] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous evaluations of inactivated whole-virus and envelope subunit vaccines to equine infectious anemia virus (EIAV) have revealed a broad spectrum of efficacy ranging from highly type-specific protection to severe enhancement of viral replication and disease in experimentally immunized equids. Among experimental animal lentivirus vaccines, immunizations with live attenuated viral strains have proven most effective, but the vaccine efficacy has been shown to be highly dependent on the nature and severity of the vaccine virus attenuation. We describe here for the first time the characterization of an experimental attenuated proviral vaccine, EIAV(UK)deltaS2, based on inactivation of the S2 accessory gene to down regulate in vivo replication without affecting in vitro growth properties. The results of these studies demonstrated that immunization with EIAV(UK)deltaS2 elicited mature virus-specific immune responses by 6 months and that this vaccine immunity provided protection from disease and detectable infection by intravenous challenge with a reference virulent biological clone, EIAV(PV). This level of protection was observed in each of the six experimental horses challenged with the reference virulent EIAV(PV) by using a low-dose multiple-exposure protocol (three administrations of 10 median horse infectious doses [HID(50)], intravenous) designed to mimic field exposures and in all three experimentally immunized ponies challenged intravenously with a single inoculation of 3,000 HID(50). In contrast, naïve equids subjected to the low- or high-dose challenge develop a detectable infection of challenge virus and acute disease within several weeks. Thus, these data demonstrate that the EIAV S2 gene provides an optimal site for modification to achieve the necessary balance between attenuation to suppress virulence and replication potential to sufficiently drive host immune responses to produce vaccine immunity to viral exposure.
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Affiliation(s)
- Feng Li
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
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8
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Kumar A, Mukherjee S, Shen J, Buch S, Li Z, Adany I, Liu Z, Zhuge W, Piatak M, Lifson J, McClure H, Narayan O. Immunization of macaques with live simian human immunodeficiency virus (SHIV) vaccines conferred protection against AIDS induced by homologous and heterologous SHIVs and simian immunodeficiency virus. Virology 2002; 301:189-205. [PMID: 12359422 DOI: 10.1006/viro.2002.1544] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To evaluate the vaccine potential of SHIVs attenuated by deletion of viral accessory genes, seven rhesus macaques were sequentially immunized with Delta vpu Delta nefSHIV-4 (vaccine-I) followed by Delta vpuSHIV(PPC) (vaccine-II). Despite the absence of virological evidence of productive infection with the vaccine strains, based on analysis of infectivity among peripheral blood mononuclear cells (PBMC) of the vaccinated animals, all seven animals developed binding as well as neutralizing antibodies against both vaccine-I and -II. The animals also developed vaccine virus-specific CTLs that recognized homologous as well as heterologous pathogenic SHIVs and SIV, and also soluble inhibitory factors that blocked the in vitro replication of the vaccine strains and different challenge viruses. Virus-specific cellular and humoral responses were sustained throughout a 58-week prechallenge period. To model aspects of natural transmission, the animals received a mucosal (rectal) challenge, with a mixture of three challenge viruses, SHIV(KU), SHIV(89.6)P, and SIV(mac)R71/17E. Two mock-vaccinated control animals inoculated with the same mixture of challenge viruses developed large numbers of infectious PBMC, high plasma viremia, and precipitous loss of CD4(+) T cells. The control animals did not develop any immune responses and succumbed to AIDS between 6 and 7 weeks postchallenge. All seven vaccinated animals became infected with challenge viruses as indicated by the presence of infectious cells in the PBMC and/or viral RNA in plasma. However, peak plasma viremia in vaccinates was two to nearly five logs lower than in the control animals and later plasma viral RNA became undetectable in all vaccinates. Vaccinated animals maintained normal CD4(+) T cell levels throughout the study. Challenge with pathogenic viruses caused massive anamnestic responses as determined by quantitation of virus-specific CD4(+) and CD8(+) T cells by intracellular IFN-gamma staining, and these cells persisted for at least 74 weeks. The study is still in progress and at this time DNA of SIV has become undetectable in lymph nodes of six of the seven vaccinates, SHIV(89.6)P in five of the seven, and SHIV(KU) in three of the seven animals.
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Affiliation(s)
- Anil Kumar
- University of Kansas Medical Center, Department of Microbiology, Molecular Genetics and Immunology, Kansas City 66160, USA.
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9
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Cole KS, Alvarez M, Elliott DH, Lam H, Martin E, Chau T, Micken K, Rowles JL, Clements JE, Murphey-Corb M, Montelaro RC, Robinson JE. Characterization of neutralization epitopes of simian immunodeficiency virus (SIV) recognized by rhesus monoclonal antibodies derived from monkeys infected with an attenuated SIV strain. Virology 2001; 290:59-73. [PMID: 11883006 DOI: 10.1006/viro.2001.1144] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A major limitation in the simian immunodeficiency virus (SIV) system has been the lack of reagents with which to identify the antigenic determinants that are responsible for eliciting neutralizing antibody responses in macaques infected with attenuated SIV. Most of our information on SIV neutralization determinants has come from studies with murine monoclonal antibodies (MAbs) produced in response to purified or recombinant SIV envelope proteins or intact SIV-infected cells for relatively short periods of time. While these studies provide some basic information on the potential immunogenic determinants of SIV envelope proteins, it is unclear whether these murine MAbs identify epitopes relevant to antibody responses elicited in monkeys during infection with either wild-type or attenuated SIV strains. To accomplish maximum biological relevance, we developed a reliable method for the production of rhesus monoclonal antibodies. In the present study, we report on the production and characterization of a unique panel of monoclonal antibodies derived from four individual monkeys inoculated with SIV/17E-CL as an attenuated virus strain at a time when protective immunity from pathogenic challenge was evident. Results from these studies identified at least nine binding domains on the surface envelope glycoprotein; these included linear determinants in the V1, V2, cysteine loop (analogous to the V3 loop in human immunodeficiency virus type 1), and C5 regions, as well as conformational epitopes represented by antibodies that bind the C-terminal half of gp120 and those sensitive to defined mutations in the V4 region. More importantly, three groups of antibodies that recognize closely related, conformational epitopes exhibited potent neutralizing activity against the vaccine strain. Identification of the epitopes recognized by these neutralizing antibodies will provide insight into the antigenic determinants responsible for eliciting neutralizing antibodies in vivo that can be used in the design of effective vaccine strategies.
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MESH Headings
- Amino Acid Sequence
- Amino Acids
- Animals
- Antibodies, Monoclonal/biosynthesis
- Antibodies, Monoclonal/immunology
- Antibodies, Viral/biosynthesis
- Antibodies, Viral/immunology
- Antigens, Viral/chemistry
- Antigens, Viral/immunology
- Binding Sites
- Binding, Competitive
- CD4 Antigens/immunology
- Cell Line
- Cross Reactions
- Epitopes, B-Lymphocyte/chemistry
- Epitopes, B-Lymphocyte/immunology
- HIV Envelope Protein gp120/chemistry
- HIV Envelope Protein gp120/immunology
- HIV-2/immunology
- Humans
- Macaca mulatta
- Membrane Glycoproteins
- Models, Molecular
- Molecular Sequence Data
- Neutralization Tests
- Peptide Fragments/immunology
- Protein Structure, Secondary
- Sequence Homology, Amino Acid
- Serine Endopeptidases
- Simian Immunodeficiency Virus/immunology
- Simian Immunodeficiency Virus/isolation & purification
- Viral Envelope Proteins
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Affiliation(s)
- K S Cole
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA
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10
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Kumar A, Lifson JD, Li Z, Jia F, Mukherjee S, Adany I, Liu Z, Piatak M, Sheffer D, McClure HM, Narayan O. Sequential immunization of macaques with two differentially attenuated vaccines induced long-term virus-specific immune responses and conferred protection against AIDS caused by heterologous simian human immunodeficiency Virus (SHIV(89.6)P). Virology 2001; 279:241-56. [PMID: 11145906 DOI: 10.1006/viro.2000.0695] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Four rhesus macaques were sequentially immunized with live vaccines DeltavpuDeltanefSHIV-4 (vaccine-I) and Deltavpu SHIV(PPC) (vaccine-II). The vaccine viruses did not replicate productively in the peripheral blood mononuclear cells (PBMCs) of the vaccinated animals. All four animals developed binding antibodies against both the vaccine-I and -II envelope glycoproteins but neutralizing antibodies only against vaccine-I. They developed vaccine virus-specific CTLs that also recognized homologous as well as heterologous pathogenic SHIVs. Thirty weeks after the last immunization, the vaccinated animals and three unvaccinated control animals were challenged iv with a highly virulent heterologous SHIV(89.6)P. As expected, the three unvaccinated control animals developed large numbers of infectious PBMCs, high plasma viremia, and precipitous loss of CD4(+) T cells. Two controls did not develop any immune response and succumbed to AIDS in about 6 months. The third control animal developed neutralizing antibodies and had a more chronic disease course, but eventually succumbed to AIDS-related complications 81 weeks after inoculation. The four vaccinated animals became infected with challenge virus as indicated by the presence of challenge virus-specific DNA in the PBMCs and RNA in plasma. However, virus in these animals replicated approximately 200- to 60,000-fold less efficiently than in control animals and eventually, plasma viral RNA became undetectable in three of the four vaccinates. The animals maintained normal CD4(+) T-cell levels throughout the observation period of 85 weeks after a transient drop at Week 3 postchallenge. They also maintained CTL responses throughout the observation period. These studies thus showed that the graded immunization schedule resulted in a safe and highly effective long-lasting immune response that was associated with protection against AIDS by highly pathogenic heterologous SHIV(89.6)P.
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Affiliation(s)
- A Kumar
- Laboratory of Viral Pathogenesis, University of Kansas Medical Center, Kansas City, Kansas, 66160, USA.
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11
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Kumar A, Buch S, Foresman L, Bischofberger N, Lifson JD, Narayan O. Development of virus-specific immune responses in SHIV(KU)-infected macaques treated with PMPA. Virology 2001; 279:97-108. [PMID: 11145893 DOI: 10.1006/viro.2000.0710] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Therapeutic intervention with highly active antiretroviral therapy (HAART) can lead to the suppression of HIV viremia below the threshold of detection for several years. However, impact of HAART on reconstitution of virus-specific immune responses remains poorly understood. In this study, four macaques were infected with pathogenic SHIV(KU). One week postinoculation two of the four animals were treated with PMPA [9-R-(2-phosphophomethoxypropyl)adenine] daily for 83 days. Two other macaques, that did not receive treatment, exhibited explosive virus replication accompanied by a near total loss of CD4(+) T cells and succumbed to AIDS-related complications within 6 months of infection. These animals did not develop any virus-specific immune responses. On the contrary, the animals that received PMPA showed transient loss of CD4(+) T cells that recovered during the treatment period. The virus burden declined below the level of detection that rebounded soon after cessation of PMPA therapy. The virus replicated productively for several weeks before both animals controlled the productive replication of virus. This control of virus replication was found to be associated with the development of virus-specific neutralizing antibodies, T-helper cells, and CTLs. Although PMPA did not eliminate virus from the animals, it provided them with enough time to mount virus-specific immune responses that eventually controlled the virus replication in the blood. Our results suggest that antiretroviral therapy, if initiated early during infection, would help the host in mounting virus-specific immune responses that might control productive replication of the virus.
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Affiliation(s)
- A Kumar
- Marion Merrell Dow Laboratory of Viral Pathogenesis, University of Kansas Medical Center, Kansas City, Kansas, 66160, USA.
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12
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Kumar A, Lifson JD, Silverstein PS, Jia F, Sheffer D, Li Z, Narayan O. Evaluation of immune responses induced by HIV-1 gp120 in rhesus macaques: effect of vaccination on challenge with pathogenic strains of homologous and heterologous simian human immunodeficiency viruses. Virology 2000; 274:149-64. [PMID: 10936096 DOI: 10.1006/viro.2000.0444] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The simian human immunodeficiency virus (SHIV) macaque model of AIDS has provided a very useful system for evaluation of envelope-based candidate vaccines against HIV-1. Eight rhesus macaques were immunized with monomeric recombinant gp120 of HIV-1(LAI) (rgp120) and used to evaluate whether this vaccine conferred protection against challenge with pathogenic SHIVs (SHIV(KU-2) and SHIV(89.6)P). The vaccinated macaques developed high titers of antibodies against rgp120 that reacted efficiently with the envelope proteins of homologous SHIV (SHIV(KU-2)) and poorly with the SHIV(89.6)P envelope, a heterologous strain of SHIV. This vaccine also induced neutralizing antibodies but only against SHIV(KU-2). Vaccine-induced antibodies were of high avidity and predominantly against linear epitopes on the protein. Vaccinated macaques developed gp120-specific T-helper cells but no consistent cytotoxic T lymphocytes. However, cellular immune responses were short-lived in all eight vaccinates. At week 22 postimmunization, four vaccinates were challenged with SHIV(KU-2) and the other four with SHIV(89.6)P. Four unvaccinated control macaques were also infected: two with SHIV(KU-2) and two with SHIV(89.6)P. Vaccinated macaques generally showed anamnestic antibody and T-helper cell responses. However, T-helper responses were again short-lived. Upon challenge, the level of productive virus replication was indistinguishable between vaccine and control groups, suggesting that rgp120 did not confer protection against virus replication when animals were challenged with homologous or heterologous SHIV viruses.
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Affiliation(s)
- A Kumar
- Laboratory of Viral Pathogenesis, Department of Microbiology, MolecularGenetics, and Immunolgy, University of Kansas Medical Center, Kansas City, Kansas 66160, USA.
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13
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Metzner KJ, Jin X, Lee FV, Gettie A, Bauer DE, Di Mascio M, Perelson AS, Marx PA, Ho DD, Kostrikis LG, Connor RI. Effects of in vivo CD8(+) T cell depletion on virus replication in rhesus macaques immunized with a live, attenuated simian immunodeficiency virus vaccine. J Exp Med 2000; 191:1921-31. [PMID: 10839807 PMCID: PMC2213531 DOI: 10.1084/jem.191.11.1921] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The role of CD8(+) T lymphocytes in controlling replication of live, attenuated simian immunodeficiency virus (SIV) was investigated as part of a vaccine study to examine the correlates of protection in the SIV/rhesus macaque model. Rhesus macaques immunized for >2 yr with nef-deleted SIV (SIVmac239Deltanef) and protected from challenge with pathogenic SIVmac251 were treated with anti-CD8 antibody (OKT8F) to deplete CD8(+) T cells in vivo. The effects of CD8 depletion on viral load were measured using a novel quantitative assay based on real-time polymerase chain reaction using molecular beacons. This assay allows simultaneous detection of both the vaccine strain and the challenge virus in the same sample, enabling direct quantification of changes in each viral population. Our results show that CD8(+) T cells were depleted within 1 h after administration of OKT8F, and were reduced by as much as 99% in the peripheral blood. CD8(+) T cell depletion was associated with a 1-2 log increase in SIVmac239Deltanef plasma viremia. Control of SIVmac239Deltanef replication was temporally associated with the recovery of CD8(+) T cells between days 8 and 10. The challenge virus, SIVmac251, was not detectable in either the plasma or lymph nodes after depletion of CD8(+) T cells. Overall, our results indicate that CD8(+) T cells play an important role in controlling replication of live, attenuated SIV in vivo.
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Affiliation(s)
- Karin J. Metzner
- Aaron Diamond AIDS Research Center, The Rockefeller University, New York, NewYork 10016
| | - Xia Jin
- Aaron Diamond AIDS Research Center, The Rockefeller University, New York, NewYork 10016
| | - Fred V. Lee
- Aaron Diamond AIDS Research Center, The Rockefeller University, New York, NewYork 10016
| | - Agegnehu Gettie
- Aaron Diamond AIDS Research Center, The Rockefeller University, New York, NewYork 10016
| | - Daniel E. Bauer
- Aaron Diamond AIDS Research Center, The Rockefeller University, New York, NewYork 10016
| | - Michele Di Mascio
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
| | - Alan S. Perelson
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
| | - Preston A. Marx
- Aaron Diamond AIDS Research Center, The Rockefeller University, New York, NewYork 10016
- Tulane Regional Primate Research Center, Covington, Louisiana 70433
| | - David D. Ho
- Aaron Diamond AIDS Research Center, The Rockefeller University, New York, NewYork 10016
| | - Leondios G. Kostrikis
- Aaron Diamond AIDS Research Center, The Rockefeller University, New York, NewYork 10016
| | - Ruth I. Connor
- Aaron Diamond AIDS Research Center, The Rockefeller University, New York, NewYork 10016
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