Identification of the Initial Targets of Transmission

项目主任/首席调查员(最后、第一、中间)：霍普，托马斯·J·霍普 艾滋病毒预防科学的最新进展包括证明长效疫苗的预防效果 可注射的卡波替格韦和针对敏感菌株的广谱中和抗体。同样，还有 在HIV疫苗科学方面取得了进展，采用了新的免疫原、佐剂和递送策略 提高对病毒的免疫反应和预防系统性感染的能力。然而， 这些预防性干预措施的微调和我们提高其效力的能力需要更好的 对艾滋病毒性传播机制的了解。这个项目的主要关注点是 关于1)开发和优化方法，允许识别在一年后感染的第一个细胞 粘膜挑战；2)扩大的感染灶的特征，以及3)定义 在日食阶段发生的一系列事件，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促进了我们对详细的自然历史的理解 在黏膜攻击后的前4天，病毒的数量减少。这一成功是创新的结果 信标引导的尸检方法，通过感染细胞的存在产生信号。这个 该技术的第一个版本利用了由复制缺陷双报告载体表达的荧光素酶。 然而，我们已经开发了这种方法的下一代，它使用64Cu标记的FAB2探针 针对SIV包膜蛋白和PET/CT的下一代信标引导尸检。这 该方法高度敏感和高效，允许无偏见地识别 全身水平的同一动物，包括病毒与宿主相互作用的特征 先天反应和炎症反应。日食期间小病灶感染的研究 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， 在同一动物体内的不同区域和组织中，它们可能会有所不同。这一点和其他观察结果揭示了 靶细胞易感性，而不是病毒包膜的“趋向性”，是早期感染的关键驱动因素。它 很明显，暴露于病毒的粘膜组织的局部解剖学和生理学对 日食阶段病毒的自然历史。通过对小组织块的审问 包含复制焦点，我们将定义早期粘膜感染的人、地点和时间，包括 哪些细胞正在产生病毒特有的警报，哪些细胞正在对这些警报做出反应。这将是 通过采用新的方法来识别迁移到感染者体内的细胞来实现 组织部位，细胞动员的限制，参与先天和炎症的通路的中断 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 阴道和直肠传播。反过来，澄清这一过程，以及局部解剖和 生理学关于病毒的扩展和传播，将明显推进艾滋病毒预防科学的发展。 相关性(请参阅说明)： 开发预防艾滋病毒感染的干预措施需要更全面地了解如何 传播开始并进展到引起全身性感染。这里提出的研究将 利用最先进的方法，可以确定病毒复制的焦点，可以定义和 其特点是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.