Cell-mediated immune responses to HIV-1 in GALT

描述（由申请方提供）：这些研究的目的是更好地了解肠道相关淋巴组织（GALT）中CD8+ T细胞应答、病毒复制和CD4+ T细胞耗竭之间的关系，并阐明GALT T细胞执行抗病毒免疫效应功能的能力。我们已经开发了方法来评估从人直肠组织新鲜分离的抗原特异性T细胞的表型和功能。对于SPECIFICAIM 1，我们将评估GALT和血液中HIV特异性CDS+ T细胞的频率、广度和功能异质性。我们推测，粘膜组织中抗原特异性CD8+ T细胞特异性的频率和范围将大于血液。血液和直肠活检样本将从（i）30名HIV感染男性和女性以及10名对照的横断面研究和（ii）20名HIV感染个体的纵向研究中获得。对于特异性目的2，我们将评估HAART对GALT中病毒载量和抗原特异性CD4+和CD8+ T细胞应答的影响。我们预测，在HAART期间，HIV特异性CD8+ T细胞应答的幅度普遍下降，同时组织病毒载量下降，尽管有些人可能在GALT中存在残留病毒和HIV特异性CD8+ T细胞。我们预测，减少病毒载量和CD4+ T细胞的再增殖将提供部分重建的CD4+ T细胞的反应，非HIV抗原，并可能导致增加细胞因子的生产HIV特异性CD8+ T细胞在GALT。在这些研究中，我们将对20名开始HAART的个体进行为期两年的纵向抽样。对于特异性AIM 3，我们将评估GALT中抗原特异性CD8+ T细胞的细胞毒性效应子功能。初步结果表明，（i）血液中的HIV特异性CTL表达低水平的穿孔素，（ii）GALT中所有CD8+ T细胞的穿孔素表达相对于血液降低，和（iii）颗粒酶A和穿孔素差异表达。我们推测GALT中的CD8+ T细胞可能功能受损。我们将比较HIV感染者和健康对照者血液和GALT中抗原特异性CD8+ T细胞的细胞毒性功能。我们还将测试替代假设来解释GALT中穿孔素表达水平明显较低的原因。

DESCRIPTION (provided by applicant): The purpose of these studies is to better understand the relationship between CD8+ T-cell responses, viral replication and CD4+ T-cell depletion in gut-associated lymphoid tissue (GALT), and to clarify the ability of GALT T-cells to perform antiviral immune effector functions. We have developed methods to assess the phenotype and function of antigen-specific T-cells freshly isolated from human rectal tissue. For SPECIFICAIM 1, we will assess the frequency, breadth and functional heterogeneity of HIV-specific CDS+ T-cells in GALT and blood. We hypothesize that the frequency and range of specificities of antigen-specific CD8+ T-cells will be greater in mucosal tissues than in blood. Blood and rectal biopsy samples will be obtained from(i) a cross-sectional study of 30 HIV-infected men and women and 10 controls and (ii) a longitudinal study of20 HIV-infected individuals. For SPECIFIC AIM 2, we will assess the effects of HAART on viral load and antigen-specific CD4+ and CD8+ T-cell responses in GALT. We predict a general decline in the magnitude of HIV-specific CD8+ T-cell responses concurrent with decreased tissue viral load during HAART, although some individuals may harbor residual virus and HIV-specific CD8+ T-cells in GALT. We predict that reduced viral load and CD4+ T-cell repopulation will provide partial reconstitution of CD4+ T-cell responses to non-HIV antigens, and may lead to increased cytokine production by HIV-specific CD8+ T-cells in GALT. For these studies, we will perform longitudinal sampling over a two-year period of 20 individuals initiating HAART. For SPECIFIC AIM 3, we will assess the cytotoxic effector functions of antigen-specific CD8+T-cells in GALT. Preliminary results suggest that (i) HIV-specific CTL in blood express low levels of perforin, (ii) perforin expression by all CD8+ T-cells is decreased in GALT relative to blood, and (iii) granzyme A and perforin are differentially expressed. We hypothesize that CD8+ T-cells in GALT may be functionally impaired. We will compare the cytotoxic function of antigen-specific CD8+ T-cells in blood and GALT of HIV-infected individuals and healthy controls. We will also test alternate hypotheses to explain the apparent low levels of perforin expression in GALT.