SUPERANTIGEN ACTIVATED T CELLS IN TUMOR IMMUNOTHERAPY

对自体肿瘤的T细胞免疫是主要的免疫应答 有可能影响疾病的结果。增强 这种通过转移淋巴细胞进行癌症治疗的免疫力， 被称为“过继免疫疗法”。这种形式的成功 治疗严重依赖于分离肿瘤致敏细胞的能力， 在癌症患者中刺激和增殖这些细胞， vitro到大量。 在动物模型中，我们已经证明淋巴 引流进行性生长肿瘤的淋巴结（LN）含有致敏T 淋巴细胞，但这样的细胞在介导抗肿瘤免疫应答方面是缺陷的。 反应然而，这些“前效应”细胞可以分化为免疫细胞。 通过体外培养的方法。一个方便的方法来刺激前- 效应细胞是使用抗CD 3和IL-2，但培养系统是 也倾向于产生不相关的T细胞。以试图 选择性激活肿瘤反应性淋巴细胞，我们最近利用 微生物超抗原超抗原与MHC II类分子结合， 形成与T细胞的不同V β片段相互作用的配体 抗原受体（TCR），而不考虑其他可变组分。中 研究得最多的超抗原是由某些革兰氏阳性菌分泌的外毒素， 细菌如金黄色葡萄球菌。他们是小单链 24至30 kDa的蛋白质，并被认为是一种 疾病的数量。我们的研究表明，一些超抗原 能够激活前效应细胞产生肿瘤- 特异性免疫效应细胞。因此，使用一组不同的 超抗原将提供一种直接分析 TCR在形成对肿瘤抗原特异性的T细胞库中的作用。 对小鼠体内施用超抗原导致大量的免疫应答。 依赖于剂量的应答T细胞的激活和缺失， 给药频率和途径。因此，调查 超抗原的潜在体内应用可能有助于设计创新方法 癌症免疫疗法此外，前效应细胞应答是 受到肿瘤诱导的特异性免疫的下调 镇压由于这种抑制中TCR的使用尚未确定， 通过超抗原的Va特异性缺失可以允许鉴定和 操纵这些重要的调节细胞。最后，创新 利用表达超抗原的肿瘤细胞的基因治疗可以提供 是指局部激活T细胞而无免疫抑制作用。 因为在体内超抗原与T细胞的相互作用导致 分泌多种淋巴因子，基于超抗原的基因治疗可 代表了与利用多个细胞因子基因的方法相当的方法。 因此，本提案的具体目标是：1）确定TCR V β 基因在超抗原抗肿瘤免疫应答中的应用 激活; 2）分析超抗原- 诱导的应答; 3）评价超抗原对小鼠的体内作用， 抗肿瘤免疫的研究进展及肿瘤诱导特异性 抑制;和4）调查可能的潜在利益， 来源于超抗原基因疗法

T cell immunity to autologous tumors is the predominant immune response that has potential to influence the outcome of disease. Augmentation of this immunity for cancer treatment by the transfer of lymphoid cells has been referred to as "adoptive immunotherapy". The success of this form of therapy is critically dependent on the ability to isolate tumor-sensitized T cells in cancer patients and to stimulate and propagate these cells in vitro to large numbers. In animal models, we have demonstrated that lymph nodes (LN) draining a progressive growing tumor contain sensitized T lymphocytes, but such cells are deficient in mediating an antitumor response. However, these "pre-effector" cells can differentiate into immune effectors by in vitro culture methods. A convenient way to stimulate pre- effector cells is the use of anti-CD3 and IL-2, but the culture system is also predisposed to the generation of irrelevant T cells. In an attempt to selectively activate tumor-reactive lymphocytes, we have recently utilized microbial superantigens. Superantigens bind to MHC class ll molecules to form ligands that interact with distinct Vbeta segments of the T cell antigen receptor (TCR) regardless of other variable components. Among the best studied superantigens are exotoxins secreted by certain Gram positive bacteria such as Staphylococcus aureus. They are small single chain proteins of 24 to 30 kDa and are implicated as the causative agents in a number of diseases. Our studies have demonstrated that some superantigens were capable of activating pre-effector cells for generation of tumor- specific immune effector cells. Thus, the use of a panel of different superantigens will provide a means to directly analyze the diversity of TCRs in shaping the T cell repertoire specific for tumor antigens. The in vivo administration of superantigens to mice leads to massive activation and deletion of responding T cells depending on the dose, frequency and route of administration. Thus, investigations into the potential in vivo use of superantigen may help design innovative approaches for cancer immunotherapy. In addition, the pre-effector cell response is subjected to down-regulation by the tumor-induced specific immune suppression. Because TCR usage in this suppression has not been determined, Va-specific deletion by superantigens may allow the identification and manipulation of these important regulatory cells. Finally, an innovative gene therapy utilizing superantigen expressing tumor cells may afford a means to locally activate T cells without immunosuppressive effects. Because in vivo interactions of superantigens with T cells lead to the secretion of a variety of lymphokines, superantigen-based gene therapy may represent an approach comparable to that utilizing multiple cytokine genes. Therefore, the specific aims in this proposal are: 1) to identify TCR Vbeta gene usage in the antitumor immune response through superantigen activation; 2) to analyze immunologic mechanisms involved in superantigen- induced responses; 3) to evaluate the in vivo effects of superantigens on the development of antitumor immunity and on tumor-induced specific suppression; and 4) to investigate the potential benefits that may he derived from superantigen-based gene therapy.