PROTECTIVE EFFICACY OF MERCK AD5 PRIME/BOOST AGAINST MUCOSAL CHALLENGE

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 目的：通过评估恒河猴的抗病毒免疫反应和疫苗方案的有效性，解决围绕人类失败的STEP HIV疫苗研究的一些挥之不去的问题。 进度： 在STEP试验之后，关于为什么疫苗方案未能防止或控制病毒复制的问题仍然存在。疫苗诱导的T细胞反应的有限广度被认为是失败的可能原因。为了解决这个问题，我们使用STEP试验方案为8只印度恒河猴接种了疫苗。在研究的第0、4和26周，用从SIVmac239获得的表达Gag、Pol1或nef的三个单独的Ad5载体以1：1：1的比例肌肉免疫猕猴。利用免疫后四周收集的冻存细胞，我们检测到很少的疫苗诱导的T细胞反应(1-2个表位/开放阅读框)与阶跃试验结果一致。然而，在第三次免疫一周后，我们检测到疫苗诱导的CD8和CD4T细胞反应，在干扰素-ELISPOT试验中平均有11个表位(1-5个表位/开放阅读框架)。令人印象深刻的是，这些CD8和CD4T细胞反应的幅度高达3,600个斑点形成细胞(SFC)/百万个PBMC和955个SFC/百万个PBMC去掉CD8细胞。我们的结果表明，选择进行免疫检测的时间点可能会影响反应的广度和疫苗方案的免疫原性。我们现在正在挑战接种疫苗的动物和8个新诺威对照组，反复限制SIVsmE660的剂量，SIVsmE660是一种与疫苗免疫原异源的病毒。 出版物： 没有。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Objective: To address some of the lingering questions surrounding the failed STEP HIV vaccine study in humans by assessing the antiviral immune responses and the efficacy of the vaccine regimen in rhesus macaques. PROGRESS: In the wake of the STEP trial, questions remain as to why the vaccine regimen failed to protect against or control virus replication. The limited breadth of vaccine-induced T-cell responses has been suggested as a possible reason for the failure. To address this, we vaccinated eight Indian Rhesus macaques using the STEP trial protocol. Macaques were immunized intramuscularly with a 1:1:1 ratio of three separate Ad5 vectors expressing gag, pol or nef derived from SIVmac239 and administered on weeks 0, 4 and 26 of the study. Using cryopreserved cells collected at four weeks post-immunization, we detected very few vaccine-induced T cell responses (1-2 epitopes/open reading frame) consistent with the STEP trial results. However, one week after the third immunization, we detected vaccine-induced CD8+ and CD4+ T-cell responses against an average of 11 epitopes in IFN-¿ ELISPOT assays (1-5 epitopes/open reading frame). Impressively, the magnitude of these CD8+ and CD4+ T-cell responses ranged up to 3,600 spot forming cells (SFC)/million PBMC and 955 SFC/million PBMC depleted of CD8+ cells. Our results suggest that the time points chosen to perform immune assays may influence the breadth of responses and the perceived immunogenicity of vaccine regimens. We are now challenging the vaccinated animals, along with eight na¿ve controls, with repeated limiting-doses of SIVsmE660, a virus heterologous to the vaccine immunogens. PUBLICATIONS: None.