PROTECTIVE EFFICACY OF MERCK AD5 PRIME/BOOST AGAINST MUCOSAL CHALLENGE

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。次级项目的主要支助 子项目的主要研究者可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 表示子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子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应答和疫苗方案的有效性，解决围绕人类STEP HIV疫苗研究失败的一些挥之不去的问题。 进展： 在STEP试验之后，关于为什么疫苗方案未能保护或控制病毒复制的问题仍然存在。疫苗诱导的T细胞应答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试验方案接种了8只印度恒河猴。用1：1：1比例的表达来源于SIVmac 239的gag、pol或nef的三种单独的Ad 5载体肌内免疫猕猴，并在研究的第0、4和26周施用。使用在免疫后4周收集的冷冻保存的细胞，我们检测到与STEP试验结果一致的非常少的疫苗诱导的T细胞应答（1-2个表位/开放阅读框）。然而，在第三次免疫后一周，我们在IFN-γ ELISPOT测定中检测到针对平均11个表位的疫苗诱导的CD 8+和CD 4 + T细胞应答（1-5个表位/开放阅读框）。令人印象深刻的是，这些CD 8+和CD 4 + T细胞应答的幅度范围高达3，600个斑点形成细胞（SFC）/百万PBMC和955个SFC/百万耗尽CD 8+细胞的PBMC。我们的研究结果表明，选择进行免疫测定的时间点可能会影响反应的广度和疫苗方案的免疫原性。我们现在用反复限制剂量的SIVsmE 660（一种与疫苗免疫原异源的病毒）挑战接种疫苗的动物，沿着8只未接种的对照动物。 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.