CMV Vectors and Early Control of Mucosal SIV Challenge

我们已经证明了CMV/SIV载体可以1)再次感染CMV+恒河猴(RM)，2)在 再次感染，通过一个强大的“效应器”诱导强大而持久的SIV特异性CD4+和CD8+T细胞反应 记忆“(T{EM})偏见，以及3)完全保护接种后约50%的RM免受进行性感染 限制剂量直肠攻击高致病性SIVmac239病毒。这种保护体现在 这些rm在突发性和程度上与以前的疫苗不同，受保护的rm显示出病毒。 在最初感染时，在不同大小的血浆中爆发，然后立即控制到无法检测到的水平。 尽管在受保护的RM中偶尔可以观察到血浆中的病毒斑点，但随着时间的推移，这些斑点会随着时间的推移而下降，1 一年来，保护不受CD8+或CD4+细胞耗尽的影响，以及广泛的组织分析 超灵敏的套式聚合酶链式反应只检测到很少的单拷贝SIV核酸，没有存活的SIV。 保护与疫苗阶段产生的总的SIV特异性CD8+T{EM}相关，并发生 却没有追忆的反应。这些数据表明了一种新的保护模式，与非常早期的 控制，可能发生在病毒进入部位和/或病毒复制和扩增的早期部位；以及 因此，CMV载体和“T{EM}”疫苗概念提供了一种新的 开发艾滋病毒/艾滋病疫苗的有效方法。在这个项目中，我们的主要目标是勾勒出 负责这一独特保护的机制，并确定数量和/或质量 保护与非保护的决定因素。首先(S.A.1)，与项目1合作，我们将使用 连续尸检方法确定黏膜攻击后SIV感染的时空进程 在未接种疫苗的RM中，病毒感染从入口到全身感染的轨迹以及 抗SIV免疫反应的研究进展。然后(S.A.2)，建立了这个基线，我们将 确定高频、基于组织的SIV特异性T细胞应答的时间和地点 RhCMV/SIV载体阻断黏膜攻击后的感染，描绘这些细胞在这一点上的功能 拦截，并确定严格病毒控制的功能要求~与响应进行比较 复制缺陷型腺病毒和痘病毒载体(项目1)和SIV减毒活疫苗引起的 (项目3)。最后(S.A.3)，我们将确定短期内潜伏和/或活跃感染的程度。 长期的RhCMV/SIV载体保护RM和这些RM中SIV特异性T细胞的活性 确定长期控制病原体的机制，并探索最终发挥作用的可能性。 清除感染。

We have demonstrated that CMV/SIV vectors can 1) re-infect CMV+ rhesus macaques (RM), 2) during re-infection, elicit potent and persistent SIV-specific CD4+ and CD8+ T cell responses with a strong "effector memory" (T{EM}) bias, and 3) completely protect ~50% of vaccinated RM from progressive infection after limiting dose rectal challenge with the highly pathogenic SIVmac239 virus. The protection manifested in these RM is distinct from previous vaccines in its abruptness and extent, with protected RM exhibiting a viral burst in plasma of varying size upon initial infection, followed by immediate control to undetectable levels. Although occasional viral blips in plasma are observed in protected RM, these decline with time, and after 1 year, protection is unaffected by CD8+ or CD4+ cell depletion, and extensive tissue analysis with ultrasensitive nested PCR has shown only rare detection of ~ single copy SIV nucleic acid and no viable SIV. Protection correlates with the total SIV-specific CD8+ T{EM} generated during the vaccine phase, and occurs without an anamnestic response. These data indicate a novel pattern of protection consistent with very early control, likely taking place at the site of viral entry and/or early sites of viral replication and amplification, and involving tissue-resident CD8+ T{EM-} Thus, CMV vectors and the "T{EM}" vaccine concept offer a new and powerful approach to HIV/AIDS vaccine development. In this project, our major goals are to delineate the mechanisms responsible for this unique protection, and determine the quantitative and/or qualitative determinants of protection vs. non-protection. First (S.A. 1), in collaboration with Project 1, we will use a serial necropsy approach to define the spatiotemporal progression of SIV infection after mucosal challenge of unvaccinated RM, both the trajectory of viral infection from the portal of entry to systemic infection, and the development of the anti-SIV immune response. Then (S.A. 2), with this baseline established, we will determine when and where the high frequency, tissue-based SIV-specific T cell responses elicited by RhCMV/SIV vectors intercept infection after mucosal challenge, delineate the function of these cells at this intercept, and determine the functional requirements for stringent viral control ~ in comparison to responses elicited by replication-deficient adenovirus and poxvirus vectors (Project 1) and live attenuated SIV vaccines (Project 3). Finally (S.A. 3), we will determine the extent of latent and/or active infection in short-term vs. long-term RhCMV/SIV vector protected RM and the activity of SIV-specific T cells in these RM, so as to determine the mechanism of long-term aviremic control, and to explore the possibility of eventual functional clearance of the infection.