The Experts below are selected from a list of 125265 Experts worldwide ranked by ideXlab platform
Stephen Whitney - One of the best experts on this subject based on the ideXlab platform.
-
antibodies with high avidity to the gp120 envelope protein in protection from simian immunodeficiency virus sivmac251 acquisition in an immunization regimen that mimics the RV 144 thai trial
Journal of Virology, 2013Co-Authors: Poonam Pegu, Monica Vaccari, Shari N Gordon, Brandon F Keele, Melvin N Doster, Yongjun Guan, Guido Ferrari, Ranajit Pal, Maria Grazia Ferrari, Stephen WhitneyAbstract:The recombinant canarypox vector, ALVAC-HIV, together with human immunodeficiency virus (HIV) gp120 envelope glycoprotein, has protected 31.2% of Thai individuals from HIV acquisition in the RV144 HIV vaccine trial. This outcome was unexpected, given the limited ability of the vaccine components to induce CD8+ T-cell responses or broadly neutralizing antibodies. We vaccinated macaques with an immunization regimen intended to mimic the RV144 trial and exposed them intrarectally to a dose of the simian immunodeficiency virus SIVmac251 that transmits few virus variants, similar to HIV transmission to humans. Vaccination induced anti-envelope antibodies in all vaccinees and CD4+ and CD8+ T-cell responses. Three of the 11 macaques vaccinated with ALVAC-SIV/gp120 were protected from SIVmac251 acquisition, but the result was not significant. The remaining vaccinees were infected and progressed to disease. The magnitudes of vaccine-induced SIVmac251-specific T-cell responses and binding antibodies were not significantly different between protected and infected animals. However, sera from protected animals had higher avidity antibodies to gp120, recognized the variable envelope regions V1/V2, and reduced SIVmac251 infectivity in cells that express high levels of α4β7 integrins, suggesting a functional role of antibodies to V2. The current results emphasize the utility of determining the titer of repeated mucosal challenge in the preclinical evaluation of HIV vaccines.
Poonam Pegu - One of the best experts on this subject based on the ideXlab platform.
-
antibodies with high avidity to the gp120 envelope protein in protection from simian immunodeficiency virus sivmac251 acquisition in an immunization regimen that mimics the RV 144 thai trial
Journal of Virology, 2013Co-Authors: Poonam Pegu, Monica Vaccari, Shari N Gordon, Brandon F Keele, Melvin N Doster, Yongjun Guan, Guido Ferrari, Ranajit Pal, Maria Grazia Ferrari, Stephen WhitneyAbstract:The recombinant canarypox vector, ALVAC-HIV, together with human immunodeficiency virus (HIV) gp120 envelope glycoprotein, has protected 31.2% of Thai individuals from HIV acquisition in the RV144 HIV vaccine trial. This outcome was unexpected, given the limited ability of the vaccine components to induce CD8+ T-cell responses or broadly neutralizing antibodies. We vaccinated macaques with an immunization regimen intended to mimic the RV144 trial and exposed them intrarectally to a dose of the simian immunodeficiency virus SIVmac251 that transmits few virus variants, similar to HIV transmission to humans. Vaccination induced anti-envelope antibodies in all vaccinees and CD4+ and CD8+ T-cell responses. Three of the 11 macaques vaccinated with ALVAC-SIV/gp120 were protected from SIVmac251 acquisition, but the result was not significant. The remaining vaccinees were infected and progressed to disease. The magnitudes of vaccine-induced SIVmac251-specific T-cell responses and binding antibodies were not significantly different between protected and infected animals. However, sera from protected animals had higher avidity antibodies to gp120, recognized the variable envelope regions V1/V2, and reduced SIVmac251 infectivity in cells that express high levels of α4β7 integrins, suggesting a functional role of antibodies to V2. The current results emphasize the utility of determining the titer of repeated mucosal challenge in the preclinical evaluation of HIV vaccines.
Michael Benenson - One of the best experts on this subject based on the ideXlab platform.
-
risk behaviour and time as covariates for efficacy of the hiv vaccine regimen alvac hiv vcp1521 and aidsvax b e a post hoc analysis of the thai phase 3 efficacy trial RV 144
Lancet Infectious Diseases, 2012Co-Authors: Merlin L Robb, Supachai Rerksngarm, Sorachai Nitayaphan, Punnee Pitisuttithum, Jaranit Kaewkungwal, Prayura Kunasol, Chirasak Khamboonruang, P Thongcharoen, Patricia Morgan, Michael BenensonAbstract:Summary Background The Thai phase 3 HIV vaccine trial RV 144 showed modest efficacy of a vaccine against HIV acquisition. Baseline variables of age, sex, marital status, and risk did not modify vaccine efficacy. We did a post-hoc analysis of the trial's data to investigate behavioural risk and efficacy every 6 months after vaccination. Methods RV 144 was a randomised, multicentre, double-blind, placebo-controlled efficacy trial testing the combination of the HIV vaccines ALVAC-HIV (vCP1521) and AIDSVAX B/E to prevent HIV infection or reduce setpoint viral load. Male and female volunteers aged 18–30 years were recruited from the community. In this post-hoc analysis of the modified intention-to-treat population (16 395 participants), HIV risk behaviour was assessed with a self-administered questionnaire at the time of initial vaccination in the trial and every 6 months thereafter for 3 years. We classified participants' behaviour as low, medium, or high risk. Both the acquisition endpoint and the early viral-load endpoint were examined for interactions with risk status over time and temporal effects after vaccination. Multiple proportional hazards regression models with treatment and time-varying risk covariates were analysed. Findings Risk of acquisition of HIV was low in each risk group, but 9187 (58·2%) participants reported higher-risk behaviour at least once during the study. Participants classified as high or increasing risk at least once during follow-up were compared with those who maintained low-risk or medium-risk behaviour as a time-varying covariate, and the interaction of risk status and acquisition efficacy was significant (p=0·01), with greater benefit in low-risk individuals. Vaccine efficacy seemed to peak early—cumulative vaccine efficacy was estimated to be 60·5% (95% CI 22–80) through the 12 months after initial vaccination—and declined quickly. Vaccination did not seem to affect viral load in either early or late infections. Interpretation Future HIV vaccine trials should recognise potential interactions between challenge intensity and risk heterogeneity in both population and treatment effects. The regimen tested in the RV 144 phase 3 trial might benefit from extended immunisation schedules. Funding US Army Medical Research and Materiel Command and Division of AIDS, National Institute of Allergy and Infectious Disease, National Institutes of Health.
Brandon F Keele - One of the best experts on this subject based on the ideXlab platform.
-
antibodies with high avidity to the gp120 envelope protein in protection from simian immunodeficiency virus sivmac251 acquisition in an immunization regimen that mimics the RV 144 thai trial
Journal of Virology, 2013Co-Authors: Poonam Pegu, Monica Vaccari, Shari N Gordon, Brandon F Keele, Melvin N Doster, Yongjun Guan, Guido Ferrari, Ranajit Pal, Maria Grazia Ferrari, Stephen WhitneyAbstract:The recombinant canarypox vector, ALVAC-HIV, together with human immunodeficiency virus (HIV) gp120 envelope glycoprotein, has protected 31.2% of Thai individuals from HIV acquisition in the RV144 HIV vaccine trial. This outcome was unexpected, given the limited ability of the vaccine components to induce CD8+ T-cell responses or broadly neutralizing antibodies. We vaccinated macaques with an immunization regimen intended to mimic the RV144 trial and exposed them intrarectally to a dose of the simian immunodeficiency virus SIVmac251 that transmits few virus variants, similar to HIV transmission to humans. Vaccination induced anti-envelope antibodies in all vaccinees and CD4+ and CD8+ T-cell responses. Three of the 11 macaques vaccinated with ALVAC-SIV/gp120 were protected from SIVmac251 acquisition, but the result was not significant. The remaining vaccinees were infected and progressed to disease. The magnitudes of vaccine-induced SIVmac251-specific T-cell responses and binding antibodies were not significantly different between protected and infected animals. However, sera from protected animals had higher avidity antibodies to gp120, recognized the variable envelope regions V1/V2, and reduced SIVmac251 infectivity in cells that express high levels of α4β7 integrins, suggesting a functional role of antibodies to V2. The current results emphasize the utility of determining the titer of repeated mucosal challenge in the preclinical evaluation of HIV vaccines.
Yongjun Guan - One of the best experts on this subject based on the ideXlab platform.
-
antibodies with high avidity to the gp120 envelope protein in protection from simian immunodeficiency virus sivmac251 acquisition in an immunization regimen that mimics the RV 144 thai trial
Journal of Virology, 2013Co-Authors: Poonam Pegu, Monica Vaccari, Shari N Gordon, Brandon F Keele, Melvin N Doster, Yongjun Guan, Guido Ferrari, Ranajit Pal, Maria Grazia Ferrari, Stephen WhitneyAbstract:The recombinant canarypox vector, ALVAC-HIV, together with human immunodeficiency virus (HIV) gp120 envelope glycoprotein, has protected 31.2% of Thai individuals from HIV acquisition in the RV144 HIV vaccine trial. This outcome was unexpected, given the limited ability of the vaccine components to induce CD8+ T-cell responses or broadly neutralizing antibodies. We vaccinated macaques with an immunization regimen intended to mimic the RV144 trial and exposed them intrarectally to a dose of the simian immunodeficiency virus SIVmac251 that transmits few virus variants, similar to HIV transmission to humans. Vaccination induced anti-envelope antibodies in all vaccinees and CD4+ and CD8+ T-cell responses. Three of the 11 macaques vaccinated with ALVAC-SIV/gp120 were protected from SIVmac251 acquisition, but the result was not significant. The remaining vaccinees were infected and progressed to disease. The magnitudes of vaccine-induced SIVmac251-specific T-cell responses and binding antibodies were not significantly different between protected and infected animals. However, sera from protected animals had higher avidity antibodies to gp120, recognized the variable envelope regions V1/V2, and reduced SIVmac251 infectivity in cells that express high levels of α4β7 integrins, suggesting a functional role of antibodies to V2. The current results emphasize the utility of determining the titer of repeated mucosal challenge in the preclinical evaluation of HIV vaccines.