BOLSTERING OF CELL MEDIATED IMMUNITY TO HUMAN CARCINOMA

引起肿瘤破坏的免疫反应可由癌细胞的MHC呈递肿瘤选择性表位，或经过抗原摄取、加工和专业APC呈递。虽然在临床前模型中已经看到肿瘤消退，并且已经获得了一些有希望的临床结果，但要使这种反应有效地对抗既定的谣言，还有很多工作要做。该提案基于申请人（前）小组的两项发现，表明通过CD28增加的共刺激和通过活化T淋巴细胞上的4-1BB受体增加的信号传导，有助于诱导针对各种小鼠肿瘤的肿瘤杀伤反应。这种诱导的反应可以破坏免疫原性非常低的肿瘤，这些肿瘤已经抵抗了其他形式的治疗，并且伴随着高的抗原特异性和MHC限制性CTL活性。拟议工作的目标是将这些信息转化为用于人类治疗用途的肿瘤疫苗的构建。作为我们的第一个目标，我们将从几种不同的人类癌（卵巢、结肠癌、乳腺癌、肺癌或肾癌）中培养细胞，表达A2单倍型的MHC I类分子，并与来自肿瘤或血液的自体淋巴细胞结合，激活/产生Th1型的肿瘤选择性CTL和T辅助反应。这将在存在或不存在通过B7-CD28的共刺激和/或通过4-1BB“触发”活化的T细胞的情况下完成，通过CD28或4-1BB的单克隆抗体或将各自的配体（CD80和/或CD86, 4-1BB配体）转染到肿瘤细胞中。实验还将研究类似的方法是否会影响已建立的肿瘤反应性T细胞克隆/系的增殖、淋巴因子产生和抗原选择性CTL活性。我们的第二个目的是研究在已知的CTL和Th1活性抑制剂（tgf - β）或Th2型淋巴因子（如il - 4）或自体恶性积液中存在的推定抑制“因子”存在的情况下，共刺激和/或4-1BB“触发”是否促进肿瘤反应性T细胞的激活/产生。这将通过直接从肿瘤或血液中获得的淋巴细胞和肿瘤反应性T细胞克隆进行研究。所获得的信息应指导构建用于人类治疗的肿瘤细胞疫苗，并应通过阐明通过CD28和4-1BB信号传导在肿瘤免疫中的作用，对其他肿瘤疫苗接种方法产生影响。

Immune responses causing tumor destruction can be induced by presentation of tumor selective epitopes by the MHC of cancer cells or after antigen uptake, processing and presentation by professional APC. While tumor regression has been seen in preclinical models and some promising clinical results have been obtained, much remains to be done to make such responses effective against established rumors. This proposal is based on two discoveries by the applicant's (former) group, showing that increased costimulation via CD28 and increased signalling via the 4-1BB receptor on activated T lymphocytes, facilitates the induction of a tumoricidal response against various mouse tumors. The response so induced can cause the destruction of established tumors of very low immunogenicity that have resisted other forms of therapy, and it is accompanied by high, antigen-specific and MHC restricted CTL activity. The goal of the proposed work is to translate this information towards the construction of tumor vaccines for therapeutic use in man. As our first aim, cells will be cultivated from several different human carcinomas (ovary, colon, breast, lung or kidney), expressing MHC class I molecules of the A2 haplotype, and combined with autologous lymphocytes from tumors or blood to activate/generate tumor-selective CTL and T helper responses of the Th1 type. This will be done in the presence or absence of costimulation via B7-CD28 and/or of "triggering" activated T cells via 4-1BB, provided either by a monoclonal antibody to CD28 or 4-1BB or by transfecting the respective ligands (CD80 and/or CD86, 4-1BB ligand) into the tumor cells. Experiments will also be performed to study whether a similar approach affects the proliferation, lymphokine production, and antigen-selective CTL activity of established, tumor-reactive T cell clones/lines. Our second aim is to investigate whether costimulation and/or 4-1BB "triggering" facilitates the activation/generation of tumor-reactive T cells in the presence of a known inhibitor of CTL and Th1 activity, TGF-beta, or a Th2 type lymphokine such as IL4, or putative inhibitory "factors" present in autologous malignant effusions. This will be studied both with lymphocytes harvested directly from tumors or blood and with tumor-reactive T cell clones. The information obtained should guide the construction of tumor cell-based vaccines for therapeutic use in man, and should have an impact also on other approaches to tumor vaccination by illustrating the role, in tumor immunity, of signalling via CD28 and 4-1BB.