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Li B, Berry N, Ham C, Ferguson D, Smith D, Hall J, Page M, Quartey-Papafio R, Elsley W, Robinson M, Almond N, Stebbings R. Vaccination with live attenuated simian immunodeficiency virus causes dynamic changes in intestinal CD4+CCR5+ T cells. Retrovirology 2011; 8:8. [PMID: 21291552 PMCID: PMC3038908 DOI: 10.1186/1742-4690-8-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Accepted: 02/03/2011] [Indexed: 01/05/2023] Open
Abstract
Background Vaccination with live attenuated SIV can protect against detectable infection with wild-type virus. We have investigated whether target cell depletion contributes to the protection observed. Following vaccination with live attenuated SIV the frequency of intestinal CD4+CCR5+ T cells, an early target of wild-type SIV infection and destruction, was determined at days 3, 7, 10, 21 and 125 post inoculation. Results In naive controls, modest frequencies of intestinal CD4+CCR5+ T cells were predominantly found within the LPL TTrM-1 and IEL TTrM-2 subsets. At day 3, LPL and IEL CD4+CCR5+ TEM cells were dramatically increased whilst less differentiated subsets were greatly reduced, consistent with activation-induced maturation. CCR5 expression remained high at day 7, although there was a shift in subset balance from CD4+CCR5+ TEM to less differentiated TTrM-2 cells. This increase in intestinal CD4+CCR5+ T cells preceded the peak of SIV RNA plasma loads measured at day 10. Greater than 65.9% depletion of intestinal CD4+CCR5+ T cells followed at day 10, but overall CD4+ T cell homeostasis was maintained by increased CD4+CCR5- T cells. At days 21 and 125, high numbers of intestinal CD4+CCR5- naive TN cells were detected concurrent with greatly increased CD4+CCR5+ LPL TTrM-2 and IEL TEM cells at day 125, yet SIV RNA plasma loads remained low. Conclusions This increase in intestinal CD4+CCR5+ T cells, following vaccination with live attenuated SIV, does not correlate with target cell depletion as a mechanism of protection. Instead, increased intestinal CD4+CCR5+ T cells may correlate with or contribute to the protection conferred by vaccination with live attenuated SIV.
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Affiliation(s)
- Bo Li
- Biotherapeutics Group, National Institute of Biological Standards and Control/Health Protection Agency, Potters Bar, Hertfordshire, UK.
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2
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Perspectives for a protective HIV-1 vaccine. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2008; 56:423-52. [PMID: 18086420 DOI: 10.1016/s1054-3589(07)56014-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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3
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Young KR, McBurney SP, Karkhanis LU, Ross TM. Virus-like particles: designing an effective AIDS vaccine. Methods 2007; 40:98-117. [PMID: 16997718 DOI: 10.1016/j.ymeth.2006.05.024] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2005] [Accepted: 05/05/2006] [Indexed: 01/10/2023] Open
Abstract
Viruses that infect eukaryotic organisms have the unique characteristic of self-assembling into particles. The mammalian immune system is highly attuned to recognizing and attacking these viral particles following infection. The use of particle-based immunogens, often delivered as live-attenuated viruses, has been an effective vaccination strategy for a variety of viruses. The development of an effective vaccine against the human immunodeficiency virus (HIV) has proven to be a challenge, since HIV infects cells of the immune system causing severe immunodeficiency resulting in the syndrome known as AIDS. In addition, the ability of the virus to adapt to immune pressure and reside in an integrated form in host cells presents hurdles for vaccinologists to overcome. A particle-based vaccine strategy has promise for eliciting high titer, long-lived, immune responses to a diverse number of viral epitopes against different HIV antigens. Live-attenuated viruses are effective at generating both cellular and humoral immune responses. However, while these vaccines stimulate immunity, challenged animals rarely clear the viral infection and the degree of attenuation directly correlates with protection from disease. Further, a live-attenuated vaccine has the potential to revert to a pathogenic form. Alternatively, virus-like particles (VLPs) mimic the viral particle without causing an immunodeficiency disease. VLPs are self-assembling, non-replicating, non-pathogenic particles that are similar in size and conformation to intact virions. A variety of VLPs for lentiviruses are currently in preclinical and clinical trials. This review focuses on our current status of VLP-based AIDS vaccines, regarding issues of purification and immune design for animal and clinical trials.
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Affiliation(s)
- Kelly R Young
- Department of Medicine, Division of Infectious Diseases, University of Pittsburgh School of Medicine, PA 15261, USA
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4
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Broche-Pierre S, Richardson J, Moraillon A, Sonigo P. Evaluation of live feline immunodeficiency virus vaccines with modified antigenic properties. J Gen Virol 2005; 86:2495-2506. [PMID: 16099908 DOI: 10.1099/vir.0.80469-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Live-attenuated viruses have typically been generated from pathogenic viruses by genetic modifications that modified their replicative capacity. The present study investigated whether modification of the antigenic properties of live-attenuated viruses might improve upon the protection that such vaccines afford against lentivirus infection. In a previous study, random amino acid substitutions were introduced into the transmembrane envelope glycoprotein of the feline immunodeficiency virus (FIV), within a highly conserved domain (principal immunodominant domain) bearing immunodominant B-cell epitopes. Amongst a wide set of mutants, mutations that modified antibody specificity without abolishing infectivity ex vivo were selected. In the present study, two such mutants, TN14 and TN92, were evaluated for their replicative capacities and pathogenic properties in vivo in comparison with the parental virus, FIV 34TF10. No significant differences in viral load were observed between mutant and parental viruses. After 1 year of infection, all animals were subjected to a heterologous intraclade superinfection with a primary strain of FIV. Whilst both parental and modified viruses protected cats from high viral loads after superinfection, the TN92 virus afforded a higher degree of protection (P=0·0079). Such improvement in protection might correlate with a decrease in the immunogenicity of a B-cell epitope potentially involved in antibody enhancement of infection.
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MESH Headings
- Amino Acid Sequence
- Amino Acid Substitution
- Animals
- Antibodies, Viral/blood
- Base Sequence
- Cat Diseases/immunology
- Cat Diseases/prevention & control
- Cat Diseases/virology
- Cats
- Epitopes, B-Lymphocyte/immunology
- Gene Products, env/administration & dosage
- Gene Products, env/genetics
- Gene Products, env/immunology
- Immunodeficiency Virus, Feline/genetics
- Immunodeficiency Virus, Feline/immunology
- Immunodeficiency Virus, Feline/pathogenicity
- Immunodominant Epitopes/immunology
- Lentivirus Infections/immunology
- Lentivirus Infections/prevention & control
- Lentivirus Infections/veterinary
- Lentivirus Infections/virology
- Molecular Sequence Data
- Vaccination
- Vaccines, Attenuated/administration & dosage
- Vaccines, Attenuated/immunology
- Vaccines, DNA/administration & dosage
- Vaccines, DNA/immunology
- Viral Vaccines/administration & dosage
- Viral Vaccines/immunology
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Affiliation(s)
- Sophie Broche-Pierre
- Génétique des Virus, Institut Cochin (INSERM U567, CNRS UMR8104), 22 rue Méchain, 75014 Paris, France
| | - Jennifer Richardson
- Génétique des Virus, Institut Cochin (INSERM U567, CNRS UMR8104), 22 rue Méchain, 75014 Paris, France
| | - Anne Moraillon
- UMR INRA-ENVA-AFSSA 1161 de Virologie, Ecole Nationale Vétérinaire d'Alfort (ENVA), 7 rue du Général de Gaulle, 94704 Maisons-Alfort, France
| | - Pierre Sonigo
- Génétique des Virus, Institut Cochin (INSERM U567, CNRS UMR8104), 22 rue Méchain, 75014 Paris, France
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5
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Pistello M, Matteucci D, Bonci F, Isola P, Mazzetti P, Zaccaro L, Merico A, Del Mauro D, Flynn N, Bendinelli M. AIDS vaccination studies using an ex vivo feline immunodeficiency virus model: protection from an intraclade challenge administered systemically or mucosally by an attenuated vaccine. J Virol 2003; 77:10740-50. [PMID: 14512524 PMCID: PMC224962 DOI: 10.1128/jvi.77.20.10740-10750.2003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Feline immunodeficiency virus (FIV) infection of domestic cats represents a valuable system through which to investigate criteria for antilentiviral vaccines in a natural host species. Here, we examined whether vaccination with a strain of FIV attenuated as a result of prolonged growth in vitro could protect against a fully virulent, highly heterologous intraclade challenge. The results indicated that the vaccine virus produced a low-grade infection with no detectable pathological effects and afforded a long-lasting sterilizing immunity if the challenge was delivered intraperitoneally as cell-free virus but not against a cell-associated intravaginal challenge. In the latter case, however, the replication and pathological consequences of the challenge virus were markedly suppressed. Together with similar results obtained in rhesus monkey models, these findings should give impulse to the development of attenuated FIV vaccines to be tested in controlled studies in field cats. Field studies may provide answers to some of the existing safety concerns surrounding attenuated AIDS vaccines in humans.
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Affiliation(s)
- Mauro Pistello
- Retrovirus Center and Virology Section, Department of Experimental Pathology, University of Pisa, Pisa, Italy
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6
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Shacklett BL, Shaw KES, Adamson LA, Wilkens DT, Cox CA, Montefiori DC, Gardner MB, Sonigo P, Luciw PA. Live, attenuated simian immunodeficiency virus SIVmac-M4, with point mutations in the Env transmembrane protein intracytoplasmic domain, provides partial protection from mucosal challenge with pathogenic SIVmac251. J Virol 2002; 76:11365-78. [PMID: 12388697 PMCID: PMC136751 DOI: 10.1128/jvi.76.22.11365-11378.2002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2002] [Accepted: 08/15/2002] [Indexed: 11/20/2022] Open
Abstract
Attenuated molecular clones of simian immunodeficiency virus (SIVmac) are important tools for studying the correlates of protective immunity to lentivirus infection in nonhuman primates. The most highly attenuated SIVmac mutants fail to induce disease but also fail to induce immune responses capable of protecting macaques from challenge with pathogenic virus. We recently described a novel attenuated virus, SIVmac-M4, containing multiple mutations in the transmembrane protein (TM) intracytoplasmic domain. This domain has been implicated in viral assembly, infectivity, and cytopathogenicity. Whereas parental SIVmac239-Nef(+) induced persistent viremia and simian AIDS in rhesus macaques, SIVmac-M4 induced transient viremia in juvenile and neonatal macaques, with no disease for at least 1 year postinfection. In this vaccine study, 8 macaques that were infected as juveniles (n = 4) or neonates (n = 4) with SIVmac-M4 were challenged with pathogenic SIVmac251 administered through oral mucosa. At 1 year postchallenge, six of the eight macaques had low to undetectable plasma viremia levels. Assays of cell-mediated immune responses to SIVmac Gag, Pol, Env, and Nef revealed that all animals developed strong CD8(+) T-cell responses to Gag after challenge but not before. Unvaccinated control animals challenged with SIVmac251 developed persistent viremia, had significantly weaker SIV-specific T-cell responses, and developed AIDS-related symptoms. These findings demonstrate that SIVmac-M4, which contains a full-length Nef coding region and multiple point mutations in the TM, can provide substantial protection from mucosal challenge with pathogenic SIVmac251.
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Affiliation(s)
- Barbara L Shacklett
- Gladstone Institute of Virology and Immunology, University of California-San Francisco, San Francisco 94141-9100, USA.
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7
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Shacklett BL, Weber CJ, Shaw KE, Keddie EM, Gardner MB, Sonigo P, Luciw PA. The intracytoplasmic domain of the Env transmembrane protein is a locus for attenuation of simian immunodeficiency virus SIVmac in rhesus macaques. J Virol 2000; 74:5836-44. [PMID: 10846063 PMCID: PMC112078 DOI: 10.1128/jvi.74.13.5836-5844.2000] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/1999] [Accepted: 03/31/2000] [Indexed: 11/20/2022] Open
Abstract
The human and simian immunodeficiency virus (HIV-1 and SIVmac) transmembrane proteins contain unusually long intracytoplasmic domains (ICD-TM). These domains are suggested to play a role in envelope fusogenicity, interaction with the viral matrix protein during assembly, viral infectivity, binding of intracellular calmodulin, disruption of membranes, and induction of apoptosis. Here we describe a novel mutant virus, SIVmac-M4, containing multiple mutations in the coding region for the ICD-TM of pathogenic molecular clone SIVmac239. Parental SIVmac239-Nef+ produces high-level persistent viremia and simian AIDS in both juvenile and newborn rhesus macaques. The ICD-TM region of SIVmac-M4 contains three stop codons, a +1 frameshift, and mutation of three highly conserved, charged residues in the conserved C-terminal alpha-helix referred to as lentivirus lytic peptide 1 (LLP-1). Overlapping reading frames for tat, rev, and nef are not affected by these changes. In this study, four juvenile macaques received SIVmac-M4 by intravenous injection. Plasma viremia, as measured by branched-DNA (bDNA) assay, reached a peak at 2 weeks postinoculation but dropped to below detectable levels by 12 weeks. At over 1.5 years postinoculation, all four juvenile macaques remain healthy and asymptomatic. In a subsequent experiment, four neonatal rhesus macaques were given SIVmac-M4 intravenously. These animals exhibited high levels of viremia in the acute phase (2 weeks postinoculation) but are showing a relatively low viral load in the chronic phase of infection, with no clinical signs of disease for 1 year. These findings demonstrated that the intracytoplasmic domain of the transmembrane Env (Env-TM) is a locus for attenuation in rhesus macaques.
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Affiliation(s)
- B L Shacklett
- Aaron Diamond AIDS Research Center, New York, NY, USA
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8
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Abstract
Live attenuated viruses can provide vaccine protection against various viral illnesses. A number of live attenuated strains of the simian immunodeficiency virus (SIV) or related lentiviruses have been evaluated in primate models as vaccine candidates against AIDS. Impressive efficacy was observed for some viruses, most notably SIV strains with deletions in the nef-gene. Sterilizing immunity was seen against homologous and heterologous virus challenge, against cell-free and cell-associated challenge, against intravenous and mucosal challenge, and against challenge as early as 3 weeks and as late as 2.25 years after just one immunization. However, these promising efficacy results are overshadowed by safety problems, such as reversion of the vaccine strain to a pathogenic virus encoding full-length nef or residual virulence of multiply deleted vaccine strains. Strategies aimed at decreasing the replicative capacity of nef-deleted vaccine strains to increase the safety profile have significantly curtailed vaccine efficacy. Nevertheless, studies of live attenuated vaccine strains should proceed and should focus on determining the correlates of vaccine protection and the molecular determinants for virulence and attenuation.
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Affiliation(s)
- R M Ruprecht
- Dana-Farber Cancer Institute, Boston MA 02115-6084, USA.
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9
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Lewis MG, Yalley-Ogunro J, Greenhouse JJ, Brennan TP, Jiang JB, VanCott TC, Lu Y, Eddy GA, Birx DL. Limited protection from a pathogenic chimeric simian-human immunodeficiency virus challenge following immunization with attenuated simian immunodeficiency virus. J Virol 1999; 73:1262-70. [PMID: 9882330 PMCID: PMC103949 DOI: 10.1128/jvi.73.2.1262-1270.1999] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two live attenuated single-deletion mutant simian immunodeficiency virus (SIV) constructs, SIV239Deltanef and SIVPBj6.6Deltanef, were tested for their abilities to stimulate protective immunity in macaques. During the immunization period the animals were examined for specific immune responses and virus growth. Each construct generated high levels of specific immunity in all of the immunized animals. The SIV239Deltanef construct was found to grow to high levels in all immunized animals, with some animals remaining positive for virus isolation and plasma RNA throughout the immunization period. The SIVPBj6.6Deltanef was effectively controlled by all of the immunized animals, with virus mostly isolated only during the first few months following immunization and plasma RNA never detected. Following an extended period of immunization of over 80 weeks, the animals were challenged with a pathogenic simian-human immunodeficiency virus (SHIV) isolate, SIV89. 6PD, by intravenous injection. All of the SIV239Deltanef-immunized animals became infected with the SHIV isolate; two of five animals eventually controlled the challenge and three of five animals, which failed to check the immunizing virus, progressed to disease state before the unvaccinated controls. One of five animals immunized with SIVPBj6.6Deltanef totally resisted infection by the challenge virus, while three others limited its growth and the remaining animal became persistently infected and eventually died of a pulmonary thrombus. These data indicate that vaccination with attenuated SIV can protect macaques from disease and in some cases from infection by a divergent SHIV. However, if animals are unable to control the immunizing virus, potential damage that can accelerate the disease course of a pathogenic challenge virus may occur.
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Affiliation(s)
- M G Lewis
- Henry M. Jackson Foundation, Walter Reed Army Institute of Research, Rockville, Maryland 20850, USA.
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10
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Pistello M, Matteucci D, Cammarota G, Mazzetti P, Giannecchini S, Del Mauro D, Macchi S, Zaccaro L, Bendinelli M. Kinetics of replication of a partially attenuated virus and of the challenge virus during a three-year intersubtype feline immunodeficiency virus superinfection experiment in cats. J Virol 1999; 73:1518-27. [PMID: 9882357 PMCID: PMC103976 DOI: 10.1128/jvi.73.2.1518-1527.1999] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The effects of preinfecting cats with a partially attenuated feline immunodeficiency virus (FIV) on subsequent infection with a fully virulent FIV belonging to a different subtype were investigated. Eight specific-pathogen-free cats were preinfected with graded doses of a long-term in vitro-cultured cell-free preparation of FIV Petaluma (FIV-P, subtype A). FIV-P established a low-grade or a silent infection in the inoculated animals. Seven months later, the eight preinfected cats and two uninfected cats were challenged with in vivo-grown FIV-M2 (subtype B) and periodically monitored for immunological and virological status. FIV-P-preinfected cats were not protected from acute infection by FIV-M2, and the sustained replication of this virus was accompanied by a reduction of FIV-P viral loads in the peripheral blood mononuclear cells and plasma. However, from 2 years postchallenge (p.c.) until 3 years p.c., when the experiment was terminated, preinfected cats exhibited reduced total viral burdens, and some also exhibited a diminished decline of circulating CD4(+) T lymphocytes relative to control cats infected with FIV-M2 alone. Interestingly, most of the virus detected in challenged cats at late times p.c. was of FIV-P origin, indicating that the preinfecting, attenuated virus had become largely predominant. By the end of follow-up, two challenged cats had no FIV-M2 detectable in the tissues examined. The possible mechanisms underlying the interplay between the two viral populations are discussed.
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Affiliation(s)
- M Pistello
- Retrovirus Center and Virology Section, Department of Biomedicine, University of Pisa, Pisa, Italy
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11
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Abstract
Because of strong clinical, pathological, virological and immunological analogies with HIV infection of humans, infection of macaques with SIV provides a valuable model for exploring crucial issues related to both the pathogenesis and prevention of HIV infection. The model has offered a unique setting for the preclinical evaluation of drugs, vaccines and gene-therapies against HIV, and has helped to identify many virus and host determinants of lentiviral disease. For instance, the importance of an intact nef gene for efficient lentivirus replication and disease induction, and the protective ability of live attenuated, nef-deleted viruses have been first demonstrated in macaques using molecular clones of SIV. More recently, the development of chimeric HIV-SIV vectors able to establish infection and induce disease in macaques has provided new opportunities for the evaluation of vaccination strategies based upon HIV antigens. The aim of this review is to describe the natural course of SIV infection in macaques and to outline how this model has contributed to our understanding of the complex interaction between lentiviruses and host immune system.
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Affiliation(s)
- A M Geretti
- Department of Virology, Royal Free and University College Medical School of UCL London (Royal Free Campus), UK
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12
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Kaur A, Grant RM, Means RE, McClure H, Feinberg M, Johnson RP. Diverse host responses and outcomes following simian immunodeficiency virus SIVmac239 infection in sooty mangabeys and rhesus macaques. J Virol 1998; 72:9597-611. [PMID: 9811693 PMCID: PMC110469 DOI: 10.1128/jvi.72.12.9597-9611.1998] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/1998] [Accepted: 08/24/1998] [Indexed: 01/29/2023] Open
Abstract
Sooty mangabeys naturally infected with simian immunodeficiency virus (SIV) do not develop immunodeficiency despite the presence of viral loads of 10(5) to 10(7) RNA copies/ml. To investigate the basis of apathogenic SIV infection in sooty mangabeys, three sooty mangabeys and three rhesus macaques were inoculated intravenously with SIVmac239 and evaluated longitudinally for 1 year. SIVmac239 infection of sooty mangabeys resulted in 2- to 4-log-lower viral loads than in macaques and did not reproduce the high viral loads observed in natural SIVsmm infection. During acute SIV infection, polyclonal cytotoxic T-lymphocyte (CTL) activity coincident with decline in peak plasma viremia was observed in both macaques and mangabeys; 8 to 20 weeks later, CTL activity declined in the macaques but was sustained and broadly directed in the mangabeys. Neutralizing antibodies to SIVmac239 were detected in the macaques but not the mangabeys. Differences in expression of CD38 on CD8(+) T lymphocytes or in the percentage of naive phenotype T cells expressing CD45RA and CD62L-selection did not correlate with development of AIDS in rhesus macaques. In macaques, the proportion of CD4(+) T lymphocytes expressing CD25 declined during SIV infection, while in mangabeys, CD25-expressing CD4(+) T lymphocytes increased. Longitudinal evaluation of cytokine secretion by flow cytometric analysis of unstimulated lymphocytes revealed elevation of interleukin-2 and gamma interferon in a macaque and only interleukin-10 in a concurrently infected mangabey during acute SIV infection. Differences in host responses following experimental SIVmac239 infection may be associated with the divergent outcome in sooty mangabeys and rhesus macaques.
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Affiliation(s)
- A Kaur
- Divisions of Immunology, New England Regional Primate Research Center, Harvard Medical School, Southborough, Massachusetts, USA
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13
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Stebbings R, Stott J, Almond N, Hull R, Lines J, Silvera P, Sangster R, Corcoran T, Rose J, Cobbold S, Gotch F, McMichael A, Walker B. Mechanisms of protection induced by attenuated simian immunodeficiency virus. II. Lymphocyte depletion does not abrogate protection. AIDS Res Hum Retroviruses 1998; 14:1187-98. [PMID: 9737590 DOI: 10.1089/aid.1998.14.1187] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To determine the role that cellular immune responses play in the protection conferred by vaccination with attenuated SIVmac32H (pC8), we have attempted to deplete macaques of their CD8+ cells prior to challenge with wild-type SIVmac32H (pJ5). In two of four pC8-infected macaques, N109 and N112, a transient partial depletion of CD8+ cells by antibody treatment was achieved. On the day of challenge peripheral CD2+CD4-CD8+ cell counts were reduced by 92 and 95%, respectively, in animals N109 and N112 and their lymph nodes revealed a 46 and 58% reduction, respectively, in CD2+CD4-CD8+ cells. Two other pC8-immunized macaques, N110 and N111, treated in the same way, did not show significant depletion of CD8+ cells. None of these four pC8-immunized animals became infected when challenged with 50 MID50 of pJ5. Treatment of a further four pC8-infected and protected macaques and two naive control animals with Campath-1H antibody successfully depleted peripheral CD3+ cell counts by >99% in all treated animals. Campath-1H depletion resulted in enhanced, longer lasting lymphoid depletion. Yet subsequent challenge with 20 MID50 of pJ5 still failed to infect the pC8-immunized animals. All eight of the naive controls, including two Campath-1H-treated animals, became infected following challenge. In summary, partial depletion of circulating CD8+ cells or total lymphocytes prior to challenge failed to abrogate the protection conferred by vaccination with pC8.
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Affiliation(s)
- R Stebbings
- Division of Immunobiology, National Institute for Biological Standards and Control, South Mimms, Potters Bar, Herts, UK
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14
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Connor RI, Montefiori DC, Binley JM, Moore JP, Bonhoeffer S, Gettie A, Fenamore EA, Sheridan KE, Ho DD, Dailey PJ, Marx PA. Temporal analyses of virus replication, immune responses, and efficacy in rhesus macaques immunized with a live, attenuated simian immunodeficiency virus vaccine. J Virol 1998; 72:7501-9. [PMID: 9696847 PMCID: PMC109989 DOI: 10.1128/jvi.72.9.7501-7509.1998] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Despite evidence that live, attenuated simian immunodeficiency virus (SIV) vaccines can elicit potent protection against pathogenic SIV infection, detailed information on the replication kinetics of attenuated SIV in vivo is lacking. In this study, we measured SIV RNA in the plasma of 16 adult rhesus macaques immunized with a live, attenuated strain of SIV (SIVmac239Deltanef). To evaluate the relationship between replication of the vaccine virus and the onset of protection, four animals per group were challenged with pathogenic SIVmac251 at either 5, 10, 15, or 25 weeks after immunization. SIVmac239Deltanef replicated efficiently in the immunized macaques in the first few weeks after inoculation. SIV RNA was detected in the plasma of all animals by day 7 after inoculation, and peak levels of viremia (10(5) to 10(7) RNA copies/ml) occurred by 7 to 12 days. Following challenge, SIVmac251 was detected in all of the four animals challenged at 5 weeks, in two of four challenged at 10 weeks, in none of four challenged at 15 weeks, and one of four challenged at 25 weeks. One animal immunized with SIVmac239Deltanef and challenged at 10 weeks had evidence of disease progression in the absence of detectable SIVmac251. Although complete protection was not achieved at 5 weeks, a transient reduction in viremia (approximately 100-fold) occurred in the immunized macaques early after challenge compared to the nonimmunized controls. Two weeks after challenge, SIV RNA was also reduced in the lymph nodes of all immunized macaques compared with control animals. Taken together, these results indicate that host responses capable of reducing the viral load in plasma and lymph nodes were induced as early as 5 weeks after immunization with SIVmac239Deltanef, while more potent protection developed between 10 and 15 weeks. In further experiments, we found that resistance to SIVmac251 infection did not correlate with the presence of antibodies to SIV gp130 and p27 antigens and was achieved in the absence of significant neutralizing activity against the primary SIVmac251 challenge stock.
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Affiliation(s)
- R I Connor
- The Aaron Diamond AIDS Research Center, The Rockefeller University, New York, New York 10016, USA.
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15
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Affiliation(s)
- MI Johnston
- The International AIDS Vaccine Initiative, c/o The Rockefeller Foundation, 420 Fifth Avenue, New York, NY 10018-2702, USA
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