Durable HIV Vaccine Targeting Mucosal Epithelium

摘要 实验性HIV/SIV疫苗产生的大量数据使人们认识到， 这种保护很可能需要2个级别的屏障，最初的一个在粘膜入口处， 第二套系统防御系统小鼠的体液和细胞免疫应答能力 粘膜组织在病毒传播的初始阶段阻断或抑制复制可能具有深刻的 对接种疫苗的宿主抵抗感染的能力的影响，即使在病毒进展超过 进入的端口，允许系统反应更多的时间来控制或根除传入的病原体。 我们假设成功的疫苗有两个必要的特征：1）如果没有， 用病毒抗原终身刺激免疫系统以维持“警戒”免疫应答;和2）a 在HIV的主要复制位点的靶向免疫应答。一种疫苗方法， 解决这两个问题将有可能实现可靠的长期积极保护。履行 为了满足这些要求，我们开发了一种新颖的策略，成功地将疫苗输送到粘膜部位， 其以重复的间隔提供抗原刺激并引发保护性粘膜免疫应答。我们 该策略利用上皮干细胞作为病毒抗原的永久但非表达来源， 分化的后代沿着生殖周期表达并呈递抗原给局部免疫系统。 使用单周期SIV（SIVsc）方法，与传统方法相比， 减毒疫苗，我们已经克隆了SIVsc基因组在外皮蛋白启动子（pINV-1）的控制下。 SIVsc），终末分化的角质形成细胞特异性启动子。当施用时，疫苗靶向和 从阴道组织中转导基底上皮干细胞。然后这些细胞增殖并分化成成熟的 上皮细胞，通过启动子触发SIV抗原表达并导致直接和交叉引发。 对于本项目，我们建议：1）确认并进一步改善 pINV-SIVsc疫苗在雌性猕猴中的作用; 2）可视化和优化疫苗递送，并研究 保护作用的基本机制; 3）使用我们最优化的疫苗策略，证明 保护免受体内病毒获得和/或病毒复制，并确定保护或 针对用异源SIV进行的重复低剂量阴道攻击的对照。

Abstract The impressive amount of data generated by experimental HIV/SIV vaccines has led to the realization that protection will most likely requires 2 levels of barriers, the initial one at the mucosal port of entry and if breached, a second set of systemic defenses. The capacity of humoral and cellular immune responses in mucosal tissues to block or contain replication at the initial stage of virus transmission may have a profound impact on the ability of a vaccinated host to resist infection, even in the case when virus progresses beyond the port of entry, allowing the systemic response more time to control or eradicate the incoming pathogen. We hypothesized that there are two necessary features for a successful vaccine: 1) A prolonged if not life-long stimulation of the immune system with viral antigens to maintain “alert” immune responses; and 2) a targeted immune response at the site of primary replication of HIV. A vaccine approach that simultaneously addresses these two issues would have the potential to achieve solid, long-term active protection. To fulfill these requirements, we have developed an original strategy to successfully deliver a vaccine to mucosal sites that provide antigen stimuli at recurrent intervals and elicit protective mucosal immune responses. Our strategy leverages epithelial stem cells as permanent but non-expressing source of viral antigen while their differentiated offspring express and present antigen to the local immune system, along the reproductive cycle. Using a single cycle SIV (SIVsc) approach, which has been shown to be safe compared to traditional attenuated vaccines, we have cloned the SIVsc genome under the control of the involucrin promoter (pINV- SIVsc), a terminally differentiated keratinocyte specific promoter. When administered, the vaccine targets and transduces basal epithelial stem cells from vaginal tissues. These then proliferate and differentiate into mature epithelial cells, triggering SIV antigen expression via the promoter and leading to both direct and cross priming. For this project, we propose: 1) To confirm and further improve the efficacy and safety profile of the pINV-SIVsc vaccine in female macaques; 2) To visualize and optimize vaccine delivery, and investigate the mechanisms of action underlying protection; and, 3) Using our best optimized vaccine strategy, demonstrate protection from virus acquisition and/or viral replication in vivo and determine the correlates of protection or control against repeated low-dose vaginal challenges with heterologous SIV.