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

描述(申请人提供)：卵巢肿瘤腹水中存在的人类记忆T细胞不能通过T细胞受体(TCR)对刺激产生反应。这种免疫抑制表现为核因子-干扰素B和κ的激活、干扰素-γ的产生和细胞对T细胞受体刺激的增殖反应的减少。当肿瘤相关T细胞(TAT)在去除肿瘤腹水后进行检测时，其无反应性很快就会被逆转。TAT的无能很容易通过添加无细胞的肿瘤腹水以剂量依赖的方式重新建立。新的初步数据证实，从腹水中分离出的两种极性脂质磷脂酰丝氨酸(PS)和GD3神经节苷脂(GD3)可在TAT中的PLCγ或其近端引起TCR信号停滞。我们的长期目标是(1)验证存在于人类卵巢肿瘤微环境中的脂类有助于TAT无能和未能控制肿瘤进展的假设，以及(2)通过阻断极性脂类的免疫抑制活性，T细胞将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的极性脂)是否直接作用于T细胞以诱导TCR信号阻断，或者这种阻断是否是由与极性脂结合并被极性脂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阻断免疫抑制脂类和/或脂结合细胞的方案提供初步的理论基础。我们预测并将在目标2中测试，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细胞的无能，防止进入肿瘤的功能性T细胞的TCR信号停滞的诱导，并将导致异种移植瘤中T细胞的杀伤。他的目标依赖于PI设计的一种新的异种移植模型，该模型首次使量化和监测肿瘤内T细胞功能和量化肿瘤细胞数量的变化成为可能。最后，对从肿瘤腹水中分离得到的两种极性脂类(PS和GD3)的结构和功能进行了研究。这些研究有望为脂质诱导的TCR信号阻断的分子机制提供进一步的见解，并导致针对和阻断每个分子抑制功能所需的特定分子结构的新方法的设计。我们提议的研究的成功得益于我们由PI组建的合作研究团队中存在的不同专业知识(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)。

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-κB and NFAT activation, IFN-γ 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 PLCγ 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.