Determinants of protection in HIV-exposed seronegative men

描述(由申请人提供)：虽然绝大多数人容易感染艾滋病毒，但极少数人即使在多次接触后仍未感染。对这些人的研究导致了一种基因多态(CCR532)的鉴定，这种多态在纯合状态下提供了防止获得性感染的保护。然而，这一发现只解释了在暴露后仍未感染的少数人；因此，必须采取其他机制来提供保护。在这一应用中，我们提出了一种探索性的分析，即遗传和先天宿主防御因素，这些因素可能在预防艾滋病毒感染方面发挥作用。通过这项应用，我们建议检查a)200名高暴露血清阴性(HESN)男男性行为者(MSM)、b)60名低危MSM对照(LRC)和c)60名感染HIV的男性队列的保护机制。与以前的倡议和我们建议的一个显著创新方面不同的是，我们不仅将选择自我报告艾滋病毒暴露风险极高的受试者，而且将尝试通过使用多层方法来检测外周循环和粘膜中艾滋病毒特异的记忆反应，以精细详细地描绘那些具有明确的生物暴露证据的受试者。通过对最有可能接触过艾滋病毒的受试者进行强有力的区分，我们将检查粘膜部位和外周血对艾滋病毒复制的内在抵抗力。我们将检测HIV联合受体CCR5在HIV暴露的粘膜部位的表达和占有率，并将检测我们首次在HESN血友病患者中报道的粘膜T细胞和循环T细胞的“静止”。我们将详细探讨自然杀伤细胞(NK)和树突状细胞(DC)群体提供的天然防御系统在粘膜和全身免受艾滋病毒感染中的作用。在不是CCR5 32纯合子的受试者中，我们将通过对250个HESN的血液样本进行全基因组测序来检查保护的遗传决定因素(除了用于所有其他研究的200个HESN外，还将收集50个HESN，以增加基因分析的能力)。还将对150名HESN和60名低危MSM对照组的直肠粘膜样本进行转录图谱分析。使用一套有效的病毒学分析方法，受损的感染性将被定位到病毒生命周期的特定阶段，以便于准确识别缺陷的来源。最后，将询问这些数据集，以更详细地探索功能性“命中”的遗传决定因素和高概率遗传“命中”的功能含义，以便协调这些不同的搜索方法。这些新颖而全面的分析结合了免疫学、病毒学和遗传学方法，使用仔细定义的艾滋病毒暴露风险的队列，将提供有关黏膜保护免受艾滋病毒感染的决定因素的关键信息。

DESCRIPTION (provided by applicant): While the vast majority of individuals are susceptible to HIV infection, a rare subset remains uninfected even after multiple exposures. Research on these persons has led to the identification of a genetic polymorphism (CCR5 32) that, in the homozygous state, provides protection against acquisition. However, this finding accounts for only a minority of persons who remain uninfected after exposure; therefore, other mechanisms must be acting to confer protection. In this application we propose an exploratory analysis of genetic and innate host defense factors that may play a role in protection from HIV infection. With this application we propose to examine mechanisms of protection among cohorts of a) 200 highly- exposed seronegative (HESN) men who have sex with men (MSM), b) 60 low risk MSM controls (LRCs), and c) 60 HIV infected men. In a departure from previous initiatives and a markedly innovative aspect of our proposal, we will not only select subjects with an extremely high self-reported risk of HIV exposure, but will attempt to delineate in exquisite detail those wih definitive evidence of biological exposure by using a multi- layered approach to detect HIV-specific anamnestic responses in the peripheral circulation and in the mucosa. With a robust discrimination of subjects most likely to have been exposed, we will examine intrinsic resistance to HIV replication at mucosal sites and in peripheral blood. We will examine the expression and occupancy of the HIV coreceptor CCR5 by peptide inhibitors at mucosal sites of HIV exposure and will examine the "quiescence" of mucosal T cells as well as in circulating T cells that we firs reported in HESN hemophiliacs. We will explore in fine detail the role of innate defenses provided by natural killer (NK) and dendritic cell (DC) populations in mucosal and systemic protection from HIV infection., Among subjects who are not CCR5 32 homozygous we will examine the genetic determinants of protection by whole-genome sequencing of blood samples from 250 HESN (50 HESN will be collected in addition to the 200 used for all other studies to increase power of the genetic analyses). Transcriptional profiles will also be performed on rectal mucosal samples from 150 HESN and 60 low risk MSM controls. Using a set of validated virologic assays, impaired infectibility will be localized to specific stages of the viral life cyce to facilitate precise identification of the source of the defect. Finally, these data sets will be interrogated to explore in greater detail the genetic determinants of functional "hits" and the functional implications of high probability genetic "hits" in order to harmonize these different search approaches. These novel and comprehensive analyses combining immunologic, virologic and genetic approaches using cohorts at carefully defined risks of HIV exposure will provide critical information on the determinants of mucosal protection from HIV infection.