scholarly journals Efficacy of Multivalent Adenovirus-Based Vaccine against Simian Immunodeficiency Virus Challenge

2009 ◽  
Vol 84 (6) ◽  
pp. 2996-3003 ◽  
Author(s):  
Danilo R. Casimiro ◽  
Kara Cox ◽  
Aimin Tang ◽  
Kara J. Sykes ◽  
Meizhen Feng ◽  
...  
Keyword(s):  
Simian Immunodeficiency Virus ◽  
Rhesus Macaques ◽  
High Dose ◽  
Virus Challenge ◽  
Study Results ◽  
Immunodeficiency Virus ◽  
Virological Outcomes ◽  
Serotype 5 ◽  
Hiv 1 ◽  
Simian Immunodeficiency Virus Challenge

ABSTRACT The prophylactic efficacies of several multivalent replication-incompetent adenovirus serotype 5 (Ad5) vaccines were examined in rhesus macaques using an intrarectal high-dose simian immunodeficiency virus SIVmac239 challenge model. Cohorts of Mamu-A*01+/B*17− Indian rhesus macaques were immunized with one of several combinations of Ad5 vectors expressing Gag, Pol, Nef, and Env gp140; for comparison, a Mamu-A*01+ cohort was immunized using the Ad5 vector alone. There was no sign of immunological interference between antigens in the immunized animals. In general, expansion of the antigen breadth resulted in more favorable virological outcomes. In particular, the order of efficacy trended as follows: Gag/Pol/Nef/Env ≈ Gag/Pol > Gag ≈ Gag/Pol/Nef > Nef. However, the precision in ranking the vaccines based on the study results may be limited by the cohort size, and as such, may warrant additional testing. The implications of these results in light of the recent discouraging results of the phase IIb study of the trivalent Ad5 HIV-1 vaccine are discussed.

scholarly journals Attenuation of Simian Immunodeficiency Virus SIVmac239 Infection by Prophylactic Immunization with DNA and Recombinant Adenoviral Vaccine Vectors Expressing Gag

2005 ◽  
Vol 79 (24) ◽  
pp. 15547-15555 ◽  
Author(s):  
Danilo R. Casimiro ◽  
Fubao Wang ◽  
William A. Schleif ◽  
Xiaoping Liang ◽  
Zhi-Qiang Zhang ◽  
...  
Keyword(s):  
Simian Immunodeficiency Virus ◽  
Peak Plasma ◽  
Rhesus Macaques ◽  
Viral Escape ◽  
Lymphoid Tissues ◽  
Vaccine Vectors ◽  
Virus Challenge ◽  
Immunodeficiency Virus ◽  
Unvaccinated Control ◽  
Serotype 5

ABSTRACT The prophylactic efficacy of DNA and replication-incompetent adenovirus serotype 5 (Ad5) vaccine vectors expressing simian immunodeficiency virus (SIV) Gag was examined in rhesus macaques using an SIVmac239 challenge. Cohorts of either Mamu-A*01(+) or Mamu-A*01(−) macaques were immunized with a DNA prime-Ad5 boost regimen; for comparison, a third cohort consisting of Mamu-A*01(+) monkeys was immunized using the Ad5 vector alone for both prime and boost. All animals, along with unvaccinated control cohorts of Mamu-A*01(+) and Mamu-A*01(−) macaques, were challenged intrarectally with SIVmac239. Viral loads were measured in both peripheral and lymphoid compartments. Only the DNA prime-Ad5-boosted Mamu-A*01(+) cohort exhibited a notable reduction in peak plasma viral load (sevenfold) as well as in early set-point viral burdens in both plasma and lymphoid tissues (10-fold) relative to those observed in the control monkeys sharing the same Mamu-A*01 allele. The degree of control in each animal correlated with the levels of Gag-specific immunity before virus challenge. However, virus control was short-lived, and indications of viral escape were evident as early as 6 months postinfection. The implications of these results in vaccine design and clinical testing are discussed.

scholarly journals A Limited Number of Simian Immunodeficiency Virus (SIV) env Variants Are Transmitted to Rhesus Macaques Vaginally Inoculated with SIVmac251

2010 ◽  
Vol 84 (14) ◽  
pp. 7083-7095 ◽  
Author(s):  
Mars Stone ◽  
Brandon F. Keele ◽  
Zhong-Min Ma ◽  
Elizabeth Bailes ◽  
Joseph Dutra ◽  
...  
Keyword(s):  
Simian Immunodeficiency Virus ◽  
Rhesus Macaques ◽  
Systemic Infection ◽  
High Dose ◽  
Macaque Model ◽  
Single Genome ◽  
Immunodeficiency Virus ◽  
Positive Time ◽  
Modeling Strategy ◽  
Hiv 1

ABSTRACT Single-genome amplification (SGA) and sequencing of HIV-1 RNA in plasma of acutely infected humans allows the identification and enumeration of transmitted/founder viruses responsible for productive systemic infection. Use of this strategy as a means for identifying transmitted viruses suggested that intrarectal simian immunodeficiency virus (SIV) inoculation of macaques recapitulates key features of human rectal infection. However, no studies have used the SGA strategy to identify vaginally transmitted virus(es) in macaques or to determine how early SIV diversification in vaginally infected animals compares with HIV-1 in humans. We used SGA to amplify 227 partial env sequences from a SIVmac251 challenge stock and from seven rhesus macaques at the earliest plasma viral RNA-positive time point after low- and high-dose intravaginal inoculation. Sequences were analyzed phylogenetically to determine the relationship of transmitted/founder viruses within and between each animal and the challenge stock. In each animal, discrete low-diversity env sequence lineages were evident, and these coalesced phylogenetically to identical or near-identical env sequences in the challenge stock, thus confirming the validity of the SGA sequencing and modeling strategy for identifying vaginally transmitted SIV. Between 1 and 10 viruses were responsible for systemic infection, similar to humans infected by sexual contact, and the set of viruses transmitted to the seven animals studied represented the full genetic constellation of the challenge stock. These findings recapitulate many of the features of sexual HIV-1 transmission in women. Furthermore, the SIV rhesus macaque model can be used to understand the factors that influence the transmission of single versus multiple SIV variants.

scholarly journals Incomplete Protection against Simian Immunodeficiency Virus Vaginal Transmission in Rhesus Macaques by a Topical Antiviral Agent Revealed by Repeat Challenges

2008 ◽  
Vol 82 (13) ◽  
pp. 6591-6599 ◽  
Author(s):  
Zandrea Ambrose ◽  
Lara Compton ◽  
Michael Piatak ◽  
Ding Lu ◽  
W. Gregory Alvord ◽  
...  
Keyword(s):  
Simian Immunodeficiency Virus ◽  
Rhesus Macaques ◽  
Target Cells ◽  
In Vivo Evaluation ◽  
Mucosal Transmission ◽  
Virus Challenge ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The rising prevalence of human immunodeficiency virus type 1 (HIV-1) infection in women, especially in resource-limited settings, accentuates the need for accessible, inexpensive, and female-controlled preexposure prophylaxis strategies to prevent mucosal transmission of the virus. While many compounds can inactivate HIV-1 in vitro, evaluation in animal models for mucosal transmission of virus may help identify which approaches will be effective in vivo. Macaques challenged intravaginally with pathogenic simian immunodeficiency virus (SIVmac251) provide a model to preclinically evaluate candidate microbicides. 2-Hydroxypropyl-β-cyclodextrin (BCD) prevents HIV-1 and SIV infection of target cells at subtoxic doses in vitro. Consistent with these findings, intravaginal challenge of macaques with SIVmac251 preincubated with BCD prevented mucosal transmission, as measured by plasma viremia and antiviral antibodies, through 10 weeks postchallenge. In an initial challenge, BCD applied topically prior to SIVmac251 prevented intravaginal transmission of virus compared to controls (P < 0.0001). However, upon a second virus challenge following BCD pretreatment, the majority of the previously protected animals became infected. The mechanism through which animals become infected at a frequency similar to that of controls after prior exposure to BCD and SIVmac251 in subsequent intravaginal virus challenges (P = 0.63), despite the potent antiviral properties of BCD, remains to be determined. These results highlight the unpredictability of antiviral compounds as topical microbicides and suggest that repeated exposures to candidate treatments should be considered for in vivo evaluation.

scholarly journals Characterization and Implementation of a Diverse Simian Immunodeficiency Virus SIVsm Envelope Panel in the Assessment of Neutralizing Antibody Breadth Elicited in Rhesus Macaques by Multimodal Vaccines Expressing the SIVmac239 Envelope

2015 ◽  
Vol 89 (16) ◽  
pp. 8130-8151 ◽  
Author(s):  
Katie M. Kilgore ◽  
Megan K. Murphy ◽  
Samantha L. Burton ◽  
Katherine S. Wetzel ◽  
S. Abigail Smith ◽  
...  
Keyword(s):  
Simian Immunodeficiency Virus ◽  
Nonhuman Primate ◽  
Neutralizing Antibodies ◽  
Rhesus Macaques ◽  
Neutralizing Antibody ◽  
Cd40 Ligand ◽  
Antibody Activity ◽  
Immunodeficiency Virus ◽  
Antibody Profile ◽  
Hiv 1

ABSTRACTAntibodies that can neutralize diverse viral strains are likely to be an important component of a protective human immunodeficiency virus type 1 (HIV-1) vaccine. To this end, preclinical simian immunodeficiency virus (SIV)-based nonhuman primate immunization regimens have been designed to evaluate and enhance antibody-mediated protection. However, these trials often rely on a limited selection of SIV strains with extreme neutralization phenotypes to assess vaccine-elicited antibody activity. To mirror the viral panels used to assess HIV-1 antibody breadth, we created and characterized a novel panel of 14 genetically and phenotypically diverse SIVsm envelope (Env) glycoproteins. To assess the utility of this panel, we characterized the neutralizing activity elicited by four SIVmac239 envelope-expressing DNA/modified vaccinia virus Ankara vector- and protein-based vaccination regimens that included the immunomodulatory adjuvants granulocyte-macrophage colony-stimulating factor, Toll-like receptor (TLR) ligands, and CD40 ligand. The SIVsm Env panel exhibited a spectrum of neutralization sensitivity to SIV-infected plasma pools and monoclonal antibodies, allowing categorization into three tiers. Pooled sera from 91 rhesus macaques immunized in the four trials consistently neutralized only the highly sensitive tier 1a SIVsm Envs, regardless of the immunization regimen. The inability of vaccine-mediated antibodies to neutralize the moderately resistant tier 1b and tier 2 SIVsm Envs defined here suggests that those antibodies were directed toward epitopes that are not accessible on most SIVsm Envs. To achieve a broader and more effective neutralization profile in preclinical vaccine studies that is relevant to known features of HIV-1 neutralization, more emphasis should be placed on optimizing the Env immunogen, as the neutralization profile achieved by the addition of adjuvants does not appear to supersede the neutralizing antibody profile determined by the immunogen.IMPORTANCEMany in the HIV/AIDS vaccine field believe that the ability to elicit broadly neutralizing antibodies capable of blocking genetically diverse HIV-1 variants is a critical component of a protective vaccine. Various SIV-based nonhuman primate vaccine studies have investigated ways to improve antibody-mediated protection against a heterologous SIV challenge, including administering adjuvants that might stimulate a greater neutralization breadth. Using a novel SIV neutralization panel and samples from four rhesus macaque vaccine trials designed for cross comparison, we show that different regimens expressing the same SIV envelope immunogen consistently elicit antibodies that neutralize only the very sensitive tier 1a SIV variants. The results argue that the neutralizing antibody profile elicited by a vaccine is primarily determined by the envelope immunogen and is not substantially broadened by including adjuvants, resulting in the conclusion that the envelope immunogen itself should be the primary consideration in efforts to elicit antibodies with greater neutralization breadth.

scholarly journals Antibody-Mediated Protection against Mucosal Simian-Human Immunodeficiency Virus Challenge of Macaques Immunized with Alphavirus Replicon Particles and Boosted with Trimeric Envelope Glycoprotein in MF59 Adjuvant

2010 ◽  
Vol 84 (12) ◽  
pp. 5975-5985 ◽  
Author(s):  
Susan W. Barnett ◽  
Brian Burke ◽  
Yide Sun ◽  
Elaine Kan ◽  
Harold Legg ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Sindbis Virus ◽  
Rhesus Macaques ◽  
High Dose ◽  
Virus Challenge ◽  
Equine Encephalitis Virus ◽  
Protein Boost ◽  
Immunodeficiency Virus ◽  
Env Protein ◽  
Vaccine Approach

ABSTRACT We have previously shown that rhesus macaques were partially protected against high-dose intravenous challenge with simian-human immunodeficiency virus SHIVSF162P4 following sequential immunization with alphavirus replicon particles (VRP) of a chimeric recombinant VEE/SIN alphavirus (derived from Venezuelan equine encephalitis virus [VEE] and the Sindbis virus [SIN]) encoding human immunodeficiency virus type 1 HIV-1SF162 gp140ΔV2 envelope (Env) and trimeric Env protein in MF59 adjuvant (R. Xu, I. K. Srivastava, C. E. Greer, I. Zarkikh, Z. Kraft, L. Kuller, J. M. Polo, S. W. Barnett, and L. Stamatatos, AIDS Res. Hum. Retroviruses 22:1022-1030, 2006). The protection did not require T-cell immune responses directed toward simian immunodeficiency virus (SIV) Gag. We extend those findings here to demonstrate antibody-mediated protection against mucosal challenge in macaques using prime-boost regimens incorporating both intramuscular and mucosal routes of delivery. The macaques in the vaccination groups were primed with VRP and then boosted with Env protein in MF59 adjuvant, or they were given VRP intramuscular immunizations alone and then challenged with SHIVSF162P4 (intrarectal challenge). The results demonstrated that these vaccines were able to effectively protect the macaques to different degrees against subsequent mucosal SHIV challenge, but most noteworthy, all macaques that received the intramuscular VRP prime plus Env protein boost were completely protected. A statistically significant association was observed between the titer of virus neutralizing and binding antibodies as well as the avidity of anti-Env antibodies measured prechallenge and protection from infection. These results highlight the merit of the alphavirus replicon vector prime plus Env protein boost vaccine approach for the induction of protective antibody responses and are of particular relevance to advancing our understanding of the potential correlates of immune protection against HIV infection at a relevant mucosal portal of entry.

scholarly journals A Period of Transient Viremia and Occult Infection Precedes Persistent Viremia and Antiviral Immune Responses during Multiple Low-Dose Intravaginal Simian Immunodeficiency Virus Inoculations

2004 ◽  
Vol 78 (24) ◽  
pp. 14048-14052 ◽  
Author(s):  
Zhong-Min Ma ◽  
Kristina Abel ◽  
Tracy Rourke ◽  
Yichuan Wang ◽  
Christopher J. Miller
Keyword(s):  
Immune Responses ◽  
Simian Immunodeficiency Virus ◽  
Low Dose ◽  
Rhesus Macaques ◽  
Systemic Infection ◽  
Variable Number ◽  
Transmission Model ◽  
High Dose ◽  
Persistent Viremia ◽  
Immunodeficiency Virus

ABSTRACT In rhesus macaques, classic systemic infection, characterized by persistent viremia and seroconversion, occurred after multiple low-dose (103 50% tissue culture infective doses) intravaginal (IVAG) inoculations with simian immunodeficiency virus (SIV) strain SIVmac251. Monkeys developed classic SIV infections after a variable number of low-dose IVAG exposures to SIVmac251. Once established, the systemic infection was identical to SIV infection following high-dose IVAG SIV inoculation. However, occult systemic infection characterized by transient cell-associated or cell-free viremia consistently occurred early in the series of multiple vaginal SIV exposures. Further, antiviral cellular immune responses were present prior to the establishment of a classic systemic infection in the low-dose vaginal SIV transmission model.

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