Re-activating Memory T Cells in the Microenvironment of Human Tumors

描述（由申请人提供）：存在于卵巢肿瘤腹水中的人类记忆T细胞不能通过T细胞受体（TCR）对刺激做出反应。这种免疫抑制表现为NF-？B和NFAT激活，IFN-？通过T细胞受体（TCR）响应刺激产生和细胞增殖。肿瘤相关T细胞（TAT）的无反应性在去除肿瘤腹水后进行检测时迅速逆转。通过以剂量依赖的方式添加无细胞肿瘤腹水，很容易重新建立TAT的能量。新的初步数据表明，从腹水中分离的两种极性脂质磷脂酰丝氨酸（PS）和GD3神经节苷脂（GD3）可诱导TCR信号在PLC附近或仅在PLC附近停止。在TAT。我们的长期目标是：(1)验证人类卵巢肿瘤微环境中存在的脂质有助于能量和TAT控制肿瘤进展失败的假设，以及(2)通过阻断极性脂质的免疫抑制活性，T细胞将被重新激活并介导原位肿瘤杀伤。Ai 1关注的是肿瘤腹水（或腹水中存在的两种免疫抑制极性脂质）是否直接作用于T细胞诱导TCR信号阻滞，还是这种阻滞是由与极性脂质结合并被极性脂质激活的细胞间接介导的。这第一个目标将为设计消除或功能性封锁免疫抑制脂质和/或脂质结合细胞的方案提供初步依据。我们预测并将在Aim 2中进行测试，阻断脂质免疫调节效应将逆转卵巢肿瘤微环境中存在的T细胞的能量，防止诱导进入肿瘤的功能性T细胞的TCR信号阻滞，并将导致T细胞杀死异种移植物中的肿瘤细胞。他的目标依赖于PI设计的一种新型异种移植模型，该模型首次可以量化和监测肿瘤内T细胞的功能，并量化肿瘤细胞数量的变化。最后，提出了从肿瘤腹水中分离的两种极性脂质（PS和GD3）的结构/功能研究。这些研究有望为脂质诱导的TCR信号阻滞的分子机制提供进一步的见解，并导致设计新的方法来靶向和阻断每个分子抑制功能所需的特定分子结构。由PI组建的合作研究团队拥有丰富的专业知识（包括免疫学、肿瘤细胞生物学、脂质生物化学、遗传学、动物建模、膜生物物理学和临床癌症免疫疗法），因此我们的研究计划取得了成功。

DESCRIPTION (provided by applicant): Human memory T cells present in ovarian tumor ascites fluids fail to respond to stimulation via the T cell receptor (TCR). This immunosuppression is manifest by decreases in NF-?B and NFAT activation, IFN-? production, and cell proliferation in response to stimulation via the T cell receptor (TCR). The non-responsiveness of the tumor-associated T cells (TAT) is quickly reversed when the cells are assayed after the removal of the tumor ascites fluid. The anergy of the TAT is easily re-established by the addition of cell free tumor ascites fluid in a dose dependent fashion. New preliminary data have established that two polar lipids phosphatidylserine (PS) and GD3 ganglioside (GD3), isolated from the ascites fluids, induce a TCR signaling arrest at or just proximal to PLC? in the TAT. Our long term goals are (1) to test the hypothesis that lipids present within human ovarian tumor microenvironments contribute to the anergy and to the failure of TAT to control tumor progression, and (2) that by blocking the immunosuppressive activity of the polar lipids T cells will become re-activated and mediate tumor killing in situ. Ai 1 focuses on whether the tumor ascites fluid, (or the two immunosuppressive polar lipids present in the ascites fluid), act directly on the T cells to induce the TCR signaling arrest or whether ths arrest is mediated indirectly by cells that bind to and are activated by the polar lipids. This firt aim will provide an initial rationale for the design of protocols to eliminate or functionally bloc the immunosuppressive lipids and/or lipid binding cells. We predict and will test in Aim 2 that blocking the lipid immunomodulatory effects will reverse the anergy of T cells present within an ovarian tumor microenvironment, prevent the induction of the TCR signaling arrest of functional T cells that enter the tumor, and will result in a T cell killing of tumor cells in the xenograft. his aim is dependent upon a novel xenograft model designed by the PI that has made it possible for the first time to quantify and monitor intratumoral T cell function and to quantify changes in tumor cell numbers. In the final aim structure/function studies of the two polar lipids (PS and GD3) isolated from the tumor ascites fluids are proposed. These studies are expected to provide further insights into the molecular mechanisms of the lipid-induced TCR signaling arrest, and to lead to the design of novel methods that target and block specific molecular structures that are found to be required for each molecule's inhibitory function. The success of our proposed studies is enhanced by the diverse expertise (including immunology, tumor cell biology, lipid biochemistry, genetics, animal modeling, membrane biophysics and clinical cancer immunotherapy) present within our collaborative research team that has been assembled by the PI.