Mechanisms of MHC-II antigen processing of HIV in macrophages and dendritic cells

描述（由申请人提供）：关于将HIV-1衍生肽加载到抗原呈递细胞（APC）表达的MHC-II分子上的精确机制知之甚少。这种在MHC-II分子上装载HIV特异性肽对于初始和特异性CD 4 + T细胞的激活是必不可少的。它必须发生，因为CD 4- T细胞反应可以在一些HIV感染者中得到证实，并且需要CD 4 + T细胞的帮助来产生在患者中观察到的抗HIV体液免疫应答。 假设：1. HIV通过特异性受体介导的机制和非特异性机制的组合进入APC，其中一些机制导致HIV肽在生产性感染发生之前在MHC-II上快速呈递。2.不同形式的HIV（HIV-1病毒粒子、活的或凋亡的HIV感染细胞和含有HIV的外泌体）以不同的效率呈递在MHC-II上。具体目标1。确定APC内化和加工HIV-1以呈递在MHC-II分子上的机制。将使用识别由人DC和巨噬细胞呈递的HIV抗原的HLA-DR限制性T细胞杂交瘤。T细胞杂交瘤用作特异性肽：MHC复合物的生物测定。该系统将允许使用抗体和药理学抑制剂来研究HIV-1的摄取、加工和呈递机制。这些研究将在单核细胞衍生的DC、单核细胞衍生的巨噬细胞、原代血髓样和浆细胞样DC以及来自结肠和宫颈阴道粘膜的原代DC和巨噬细胞中进行。将通过高分辨率显微镜对DC中HIV的细胞内运输进行定量分析。具体目标2。确定MHC-II分子最有效加工和呈递的HIV-1或HIV-1抗原的形式。将在人单核细胞衍生的和原代APC中研究HIV-1病毒体、HIV感染细胞（活细胞和凋亡细胞）和含HIV外泌体的MHC-II抗原呈递。 更好地了解HIV-1的MHC-II抗原呈递将有助于早期了解事件 在感染中，当CD 4 + T细胞被引发并且CTL和B细胞应答的特征被 这取决于他们接受的CD 4 + T细胞帮助的质量。更好地了解HIV抗原的最佳呈现形式将有助于疫苗的设计和开发。所获得的知识可能有助于制定策略，以调节APC中的HIV感染，使其偏向降解途径，而不是导致CD 4 + T细胞的生产性感染或转感染的途径。

DESCRIPTION (provided by applicant): Little is known about the precise mechanism of loading of peptides derived from HIV-1 onto MHC-II molecules expressed by antigen presenting cells (APC). This loading of HIV specific peptide on MHC-II molecules is essential for the activation of both na¿ve and specific CD4+ T cells. It must occur because CD4- T cell responses can be demonstrated in some HIV-infected persons, and CD4+ T cell help is required to generate the anti-HIV humoral immune responses observed in patients. Hypothesis: 1. That HIV enters APC through a combination of specific receptor mediated mechanisms and nonspecific mechanisms some of which lead to rapid presentation of HIV peptides on MHC-II before productive infection occurs. 2. That different forms of HIV (HIV-1 virions, live or apoptotic HIV-infected cells, and HIV-containing exosomes) are presented on MHC-II with different efficiencies. Specific Aim 1. To determine the mechanism(s) used by APC to internalize and process HIV-1 for presentation on MHC-II molecules. HLA-DR restricted T cell hybridomas that recognize HIV antigens presented by human DC and macrophages will be used. T cell hybridomas serve as a bioassay for specific peptide:MHC complexes. This system will allow the use antibody and pharmacologic inhibitors to study the mechanisms of uptake, processing, and presentation of HIV-1. These studies will be performed in monocyte derived DC, monocyte derived macrophages, primary blood myeloid and plasmacytoid DC, and primary DC and macrophages from colonic and cervicovaginal mucosa. Quantitative analysis of intracellular trafficking of HIV in DC will be performed by high-resolution microscopy. Specific Aim 2. To determine the form of HIV-1 or HIV-1 antigen most efficiently processed and presented by MHC-II molecules. MHC-II antigen presentation of HIV-1 virions, HIV infected cells (live and apoptotic), and HIV-containing exosomes will be studied in human monocyte derived and primary APC. A better understanding of MHC-II antigen presentation of HIV-1 will aid in understanding events early in infection when CD4+ T cells are primed and the character of CTL and B cell responses is being determined by the quality of CD4+ T cell help they receive. A better understanding of the optimal forms of HIV antigen for presentation will aid in vaccine design and development. Knowledge gained may help aid in developing strategies to modulate HIV infection in APC to bias toward degradative pathways and not those that result in productive infection or trans-infection of CD4+ T cells.