CMV Vectors and Early Control of Mucosal SIV Challenge

我们已经证明，CMV/SIV载体可以1）再感染CMV+恒河猴（RM），2）在感染过程中， 再次感染，引发有效和持久的SIV特异性CD 4+和CD 8 + T细胞应答， 记忆”（T{EM}）偏倚，3）完全保护约50%的接种RM在接种后免受进行性感染 用高致病性SIVmac 239病毒进行限制剂量直肠攻击。保护体现在 这些RM在其不敏感性和程度上不同于以前的疫苗，受保护的RM表现出病毒性 在初始感染时在不同大小的血浆中爆发，随后立即控制到不可检测的水平。 虽然在受保护的RM中偶尔观察到血浆中的病毒斑点，但这些斑点随着时间的推移而下降，并且在1 一年，保护不受CD 8+或CD 4+细胞耗竭的影响， 超灵敏的巢式PCR仅显示出罕见的~单拷贝SIV核酸的检测，并且没有活的SIV。 保护与疫苗接种阶段产生的总SIV特异性CD 8 + T{EM}相关， 没有记忆反应这些数据表明一种新的保护模式， 控制，可能发生在病毒进入位点和/或病毒复制和扩增的早期位点，和 因此，CMV载体和“T{EM}”疫苗概念提供了一种新的且 艾滋病毒/艾滋病疫苗开发的有力方法。在这个项目中，我们的主要目标是描绘 负责这种独特保护的机制，并确定定量和/或定性 保护与不保护的决定因素。First（S.A.）1），与项目1合作，我们将使用 一种确定粘膜激发后SIV感染时空进展的连续尸检方法 对于未接种疫苗的RM，病毒感染从入口到全身感染的轨迹，以及 抗SIV免疫反应的发展。然后（S.A. 2），在确定了这一基线后，我们将 确定何时何地高频率，基于组织的SIV特异性T细胞反应引起的 RhCMV/SIV载体在粘膜攻击后拦截感染，描述这些细胞在此过程中的功能。 拦截，并确定与响应相比的严格病毒控制的功能要求 由复制缺陷型腺病毒和痘病毒载体（项目1）和减毒SIV活疫苗引起 （项目3）。最后，S。3），我们将确定短期内潜伏和/或活动性感染的程度， 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，以便 确定长期禽流感控制的机制，并探讨最终功能性 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.