Platelet-medicated deregulation of dendritic cell function- implications for anti-HIV immune responses and immunotherapy

摘要 我们将检验这一假设，即血小板-单核细胞和血小板-DC复合体的破坏将导致 改善DC的功能，从而提高a)自发控制艾滋病毒和b) 树突状细胞为主的免疫治疗的疗效观察我们已经报道，艾滋病毒感染导致高达2倍 循环中的血小板-单核细胞复合体(PMC)增加，导致单核细胞异常激活。 我们最新的体外初步数据显示，来自PMC(MoDC)的DC表达减少的几个 对DC功能至关重要的分子(如CD206、DC-SIGN、CD80、CD86、CCR7)，并显示抗原摄取减少 诱导幼稚的CD4和CD8T细胞增殖及IL-12分泌减少的能力 CD40L刺激。共培养上清液中转化生长因子水平的升高提示该分子 可能参与了血小板对MODC的抑制作用。我们还检测到了直接的复合体 HIV+和HIV-个体全血中的血小板和循环树突状细胞(CDCs)与 CD40和CD80的表达降低表明，与其他白细胞一样，血小板可以影响 内源性DC功能。在这些观察的指导下，在目标1中，我们将确定血小板对 内源性血液分离的cDC1、cDC2、PDC和MoDC的免疫原性为此，感染了艾滋病毒， 接受CART治疗的和未感染的接受或不接受抗血小板治疗的患者将使用我们的Active 协议。将分析循环DC与血小板的相互作用和共刺激分子的表达 分子和趋化因子受体。这些发现将与血小板活化的测量和 Elispot的艾滋病毒特异性免疫反应。此外，疾控中心(直接从血液中分离)或MoDC将 与血小板复合以评价其产生的免疫刺激和抑制因子，并用于 评估原始的CD4和CD8T细胞的抗原提呈，向淋巴导向的迁移 趋化因子(CCL21，CCL19)，体外诱导抗HIV和对照抗原的Th1和CTL反应 细胞毒作用。目的2，确定转化生长因子和前列腺素E_2信号在血小板调节中的作用 MODC和CDC的功能。将使用转化生长因子和前列腺素E_2的封闭抗体/抑制剂。身份识别 与血小板的DC调制效应相关的关键信号事件将使我们能够开发新的策略 改善感染者固有的抗艾滋病毒免疫反应，可能还有其他慢性疾病 包括癌症。

ABSTRACT We will test the hypothesis that the disruption of platelet-monocyte and platelet-DC complexes will result in improved function of DCs, thereby increasing the efficacy of a) spontaneous control of HIV and b) the therapeutic effects of DC based immunotherapy. We have reported that HIV infection results in up to 2-fold increase in circulating platelet-monocyte complexes (PMCs) resulting in undesirable activation of monocytes. Our latest in vitro preliminary data show that DCs derived from PMCs (MoDCs) express reduced levels of several molecules critical to DC function (e.g. CD206, DC-SIGN, CD80, CD86, CCR7) and show reduced antigen uptake capacity, ability to induce the proliferation of naïve CD4 and CD8 T cells and decreased IL-12 secretion upon stimulation with CD40L. Increased levels of TGF in co-culture supernatants are suggestive that this molecule may mediate the suppressive effects of platelets on MoDCs. We also detected direct complexes between platelets and circulating DCs (cDCs) in whole blood of HIV+ and HIV- individuals, that were associated with decreased expression of CD40 and CD80 suggesting that, similar to other leukocytes, platelets can influence endogenous DC function.Guided by these observations, in Aim 1 we will determine the effect of platelets on the immunogenic functions of endogenous blood-isolated cDC1, cDC2, pDC and MoDC. To this end, HIV infected, cART treated and uninfected individuals on or not on anti-platelet therapy will be enrolled using our active protocols. Circulating DCs will be analyzed for their interaction with platelets and expression of costimulatory molecules and chemokine receptors. These findings will be correlated with measures of platelet activation and HIV specific immune responses by ELISPOT. Further, cDCs (directly isolated from blood) or MoDCs will be complexed with platelets to evaluate their production of immunostimultory and suppressive factors, and used to evaluate antigen presentation to naïve CD4 and CD8 T cells, migration towards lymph-node-directing chemokines (CCL21, CCL19), in vitro induction of Th1 and CTL responses against HIV and control antigens and cytotoxic function. Aim 2, will determine the role of TGF and PGE2 signaling in platelet-mediated modulation of MoDC and cDC function. Blocking antibodies/inhibitors of TGF and PGE2 will be used. Identification of the key signaliing events associated with DC-modulating effects of platelets will allow us to develop new strategies to improve inherent anti-HIV immune responses in infected individuals, and, potentially other chronic disorders including cancer.