ANERGY, APOPTOSIS AND CD28 IN CD8+ T CELLS DURING AIDS

HIV感染中的效应者CD8+T细胞负责最初的病毒血症控制，然而，HIV特异性CTL 记忆细胞在疾病进展过程中由于一种未知的机制而丢失。我们的数据显示，HIV+患者 含有HIV特异性的CD8+CD28m细胞，它们通过单核细胞通过共刺激而死亡。另外，我们发现出血热病毒 在体外引起CD28配体(CD80和CD86)的过度表达，诱导CD28丢失和CD8+细胞凋亡 T细胞。这些观察结果表明，CD8+T细胞能够成为记忆的基本机制 HIV特异性CTL可能在疾病进展过程中选择性丢失。为了研究这一假设，我们提出了三个假设 目标。目的1研究CD28下调和细胞凋亡的机制。使用CHO细胞系和 定义水平的共刺激配体CD80或CD86，与纯化的T细胞孵育，我们将评估机制 负责CD28下调和细胞凋亡。为了检验艾滋病毒感染的重要性，我们将混合 自身感染HIV的巨噬细胞与T细胞，检测巨噬细胞上CD80和CD86的表达，AS 以及细胞接触、巨噬细胞释放的可溶性因子或细胞因子对CD28下调的影响。 CDS T细胞的调节和凋亡。因为人们对CD28的分子调控知之甚少 表达，Aim 2将通过检测NF-2的差异结合来检测CD28启动子的下调。 KBA和/或STAT-6蛋白，这将为防止CD28丢失提供分子基础。人工神经网络3将会发展 增加HIV中抗原特异性记忆CD8+T细胞的潜在治疗方法。使用同种异体抗原作为 模型中，我们将调节共刺激、激活条件、时间、信号强度和细胞因子。最多的 有希望的增加记忆CD8+T细胞的方法将用于HIV感染患者的CD8+T细胞。 因为CD8+T细胞对HIV的控制很重要，所以这些研究对发展免疫学很重要 干预策略和疫苗设计。

Effector CD8+ T cells in HIV infection are responsible for initial viremia control, however, HIV-specific CTL memory cells are lost during disease progression by an unknown mechanism. Our data show that HIV+ patients contain HIV-specific CD8+CD28 m cells which die by costimulation via monocytes. hi addition, we found that HFV causes over-expression of the CD28 ligands (CD80 and CD86) in vitro, inducing CD28 loss and apoptosis of CD8+ T cells. These observations suggest a fundamental mechanism whereby CD8+ T cells capable of becoming memory HIV-specific CTL could be selectively lost during disease progression. To study this hypothesis we propose three aims. Aim 1examines mechanisms for CD28 down-regulation and apoptosis. Using mixtures of CHO cell lineswith defined levels of costimulatory ligands, CD80 or CD86, incubated with purified T cells, we will assess mechanisms responsible for CD28 down-regulation and apoptosis. To examine the importance of HIV infection, we will mix autologous HIV-infected macrophages with T cells, examine CD80 and CD86 expression on the macrophages, as well as the effects of cell contact, soluble factors or cytokines released by the macrophages on CD28 down- regulation and apoptosis of the CDS T cells. Because little is known about molecular regulation of CD28 expression, Aim 2 will examine the down-regulation of the CD28 promoter by testing differential binding of NF- kBa and/or STAT-6 proteins, which will provide a molecular basis for prevention of CD28 loss. Ann 3 willdevelop potential therapeutic methods to increase antigen-specific memory CD8+ T cells in HIV. Using alloantigen as a model, we will modulate costimulation, activation conditions, timing, strength of signals, and cytokines. The most promising methods to increase memory CD8+ T cells will be used with CD8+ T cells from HIV-infected patients. Because CD8+ T cells are important for HIV control, these studies are important for development of immune intervention strategies and for vaccine design.