TRANSGENIC MODEL FOR CARCINOEMBRYONIC ANTIGEN VACCINES

这项提案的长期目标是发展免疫疗法 基于引发对自身免疫反应的策略 癌胚抗原（CEA），广泛表达于人类 结肠癌乳腺癌和肺癌 作为实现 为了达到这一目的，已经制备了人CEA转基因小鼠作为以下模型： 研究CEA耐受性和启动或引入CEA的影响， CEA免疫应答对正常组织功能和肿瘤 增长 初步研究表明，就组织而言， CEA表达的分布模式及其抗原耐受性 CEA转基因小鼠与人类非常相似。 在第一个目标中，T细胞 将在T辅助细胞和细胞毒性细胞中研究CEA耐受性 车厢 在用可溶性CEA或抗原表达免疫后， 细胞，淋巴细胞转化，细胞因子释放，抗半抗原抗体 形成，迟发型超敏反应试验将测量T细胞 响应能力。 对于第二个目的，将研究B细胞对CEA的耐受性。 考察 由辅助物非依赖性CEA缀合物组成的免疫原，或 细胞因子融合蛋白将用于刺激抗体形成。 的 所引发的抗体的结合、效力和类别特性将被 测定 在第三个目标中，体液免疫和细胞免疫的作用 在体内介导肿瘤细胞破坏中对CEA的应答将是 使用用CEA转染的同基因鼠肿瘤进行分析。 保护 将在用CEA免疫后研究抗肿瘤生长的作用。 表达成纤维细胞沿着细菌佐剂。 可能机制 将使用体内淋巴细胞耗竭进行肿瘤根除， 过继转移，以及T细胞效应子活性的体外测定， 抗体特异性和性质，以及抗体依赖性细胞 细胞毒 将使用细胞疫苗或可溶性抗原进行免疫接种以偏倚 无论是细胞或体液反应CEA进一步剖析他们的作用 介导肿瘤破坏。 作为上述目标的一部分， 与CEA交叉反应的抗CEA应答 将建立抗原。 为了达到最终目的， 来源于非转基因小鼠的抗CEA细胞毒性T细胞的特性 将在过继转移后的转基因动物中进行研究。 这 提出了一种用于过继治疗的模型，作为规避要求的手段 来破坏耐受性和控制可能的自身免疫反应。 在这一目标下的研究将使用以下方法来确定免疫显性CEA表位： 具有预测的I类结合基序的肽或通过分离天然的 加工肽。 在所有的研究中，自身免疫性疾病的可能出现 将表征伴随抗CEA应答性的反应。

The long-term goal of this proposal is the development of immunotherapy strategies that are based on eliciting immune responsiveness to a self antigen, carcinoembryonic antigen (CEA), that is widely expressed on human colon, breast, and lung carcinomas. As a first step towards accomplishing this goal, mice transgenic for human CEA have been prepared as a model for investigating CEA tolerance and the effects that initiating or introducing immune responsiveness to CEA have on normal tissue function and tumor growth. Preliminary studies have shown that with respect to the tissue distribution pattern of CEA expression and their antigen tolerance these CEA transgenic mice closely resemble humans. In the first aim, T cell tolerance to CEA will be studied in both the T helper and cytotoxic cell compartment. Following immunization with soluble CEA or antigen-expressing cells, lymphocyte transformation, cytokine release, anti-hapten antibody formation, and delayed hypersensitivity tests will measure T cell responsiveness. For the second aim, B cell tolerance to CEA will be examined. Immunogens consisting of helper-independent CEA conjugates or cytokine fusion proteins will be used to stimulate antibody formation. The binding, potency, and class properties of elicited antibodies will be determined. In the third aim, the roles of humoral and cellular immune responses to CEA in mediating destruction of tumor cells in vivo will be analyzed using syngeneic murine tumors transfected with CEA. Protection against tumor growth will be studied following immunization with CEA- expressing fibroblasts along with bacterial adjuvant. Possible mechanisms of tumor eradication will be pursued using in vivo lymphocyte depletion and adoptive transfer, and in vitro assays of T cell effector activity, antibody specificity and nature, and antibody-dependent cellular cytotoxicity. Immunization with cell vaccine or soluble antigen will be used to bias either a cellular or humoral response to CEA to dissect further their roles in mediating tumor destruction. As part of the above aims, the specificity of anti-CEA responses that appear with respect to CEA cross-reactive antigens will be established. For the final aim, the therapeutic properties of anti-CEA cytotoxic T cells derived from nontransgenic mice will be studied in transgenic animals following adoptive transfer. This model for adoptive therapy is proposed as a means to circumvent requirement for breaking tolerance and to control possible autoimmune reactions. Studies under this aim will define the immunodominant CEA epitopes using peptides with predicted class I binding motifs or by isolation of naturally processed peptide. In all studies, the possible appearance of autoimmune reactions accompanying anti-CEA responsiveness will be characterized.