Identification of the Initial Targets of Transmission

项目负责人/主要研究者（最后，第一，中间）：霍普，托马斯J。 艾滋病预防科学的最新进展包括证明了长效 注射用卡博特拉韦和针对敏感菌株的广泛中和抗体。同样， 在HIV疫苗科学方面取得了进展，新的免疫原，佐剂和递送策略， 增加对病毒的免疫反应和预防全身感染的能力。但 这些预防性干预措施的微调以及我们提高其效力的能力需要更好的 了解艾滋病毒性传播的机制。该项目的主要重点是 1）开发和优化方法，允许鉴定在感染后感染的第一个细胞， 粘膜挑战; 2）扩大的感染病灶的表征，和3） 在日食阶段发生的一连串事件，因为病毒在可检测到之前传播 病毒血症。这个项目独特地影响和推进了我们对详细自然历史的理解 在粘膜攻击后的前4天内病毒的感染。这种成功是创新的结果。 信标引导的尸检方法，其中通过感染细胞的存在产生信号。的 该技术的第一个版本利用由复制缺陷型双报告载体表达的荧光素酶。 然而，我们已经开发了下一代这种方法，它使用64 Cu标记的FAB 2探针 特异性针对SIV包膜蛋白和PET/CT作为下一代信标引导尸检。这 该方法是高度敏感和有效的，允许无偏地识别多个病灶内的 同一动物全身水平，包括病毒与宿主相互作用的表征 先天性和炎症反应。对食饵期小病灶感染的研究 传播揭示了不同感染细胞和局部组织环境之间的复杂串扰， 其在同一动物的不同区域和组织中可能不同。这和其他观察揭示了 早期感染的关键驱动因素是靶细胞的易感性，而不是病毒包膜的“向性”。它 显然，暴露于病毒的粘膜组织的局部解剖学和生理学对 病毒在日蚀期的自然发展史通过对小组织块的研究 包含复制病灶，我们将确定早期粘膜感染的患者、地点和时间，包括 哪些细胞产生病毒特异性警报以及哪些细胞响应这些警报。这将 通过结合新的方法来识别迁移到感染细胞中的细胞， 组织部位，细胞动员的限制，参与先天性和炎性 反应，以及感染组织内的短期和长期反应。推进目标和重点 这一项目的实施将大大增加我们对2010年最早的级联事件的了解。 阴道和直肠传播。反过来，阐明这一过程，以及局部解剖和 生理学对病毒扩展和传播的研究，将明显推进艾滋病预防科学。 相关性（参见说明）： 制定预防艾滋病毒感染的干预措施需要更全面地了解 传播开始并发展到引起全身感染。本文提出的研究将 利用最先进的方法，可以确定病毒复制的病灶， 以指导艾滋病毒预防方法的优化。

Program Director/Principal Investigator (Last, First, Middle): Hope, Thomas J. Recent advances in HIV Prevention science include the demonstration of PreP efficacy of the long acting injectable Cabotegravir and broadly neutralizing antibodies against sensitive strains. Likewise, there have been advances in HIV vaccine science with novel immunogens, adjuvants, and delivery strategies that are increasing the immune responses to the virus and their ability to prevent systemic infection. However, the fine tuning of these preventative interventions and our ability to increase their potency require a better understanding of the mechanisms of HIV sexual transmission. The primary focus of this project has been on 1) developing and optimizing methods allowing the identification of the first cells infected after a mucosal challenge; 2) the characterization of the expanding foci of infection, and 3) the definition of the cascade of events that takes place during the eclipse phase as the virus disseminates before detectable viremia. This project has uniquely impacted and advanced our understanding of the detailed natural history of the virus in the first 4 days after mucosal challenge. This success is a consequence of the innovative approach of beacon-guided necropsy where a signal is generated by the presence of infected cells. The first version of this technique utilized luciferase expressed by a replication defective dual-reporter vector. However, we have developed the next generation of this approach, which uses 64Cu labeled FAB2 probes specific for the SIV envelope protein and PET/CT as next generation beacon-guided necropsy. This approach is highly sensitive and efficient allowing the unbiased identification of multiple foci within the same animal at the whole-body level including the characterization of the interactions of the virus with host innate and inflammatory responses. The study of small foci of infection during the eclipse phase after transmission reveals a complex crosstalk between different infected cells and local tissue environment, which can vary in different areas and tissues within the same animal. This and other observations reveal target cell susceptibility, rather than the “tropism” of the viral envelope, is the key driver of early infection. It is clear that the local anatomy and physiology of virus exposed mucosal tissue has a major impact on the natural history of the virus during the eclipse phase. Through the interrogation of small tissue blocks containing replication foci, we will define the who, where, and when of early mucosal infection, including which cells are generating virus specific alarms and which cells are responding to these alarms. This will be accomplished by incorporating new approaches for the identification of cells migrating into the infected tissue site, restriction of cell mobilization, the disruption of pathways involved in innate and inflammatory responses, and short and long term responses within the infected tissues. Advancing the goals and focus of this project will result in a substantial increase in our understanding of the earliest cascade events in vaginal and rectal transmission. In turn, clarifying this process, and the impact of local anatomy and physiology on virus expansion and dissemination, will clearly advance HIV prevention science. RELEVANCE (See instructions): Developing interventions to prevent HIV infections requires a more complete understanding of how transmission is initiated and progresses to cause systemic infection. The studies proposed here will leverage state-of-the-art methodologies that can identify foci of viral replication that can be defined and characterized to guide optimization of HIV prevention approaches.