TRANSGENIC MODEL FOR CARCINOEMBRYONIC ANTIGEN VACCINES

这项提议的长期目标是发展免疫疗法。 基于激发对自身的免疫反应的策略 癌胚抗原(CEA)，在人类身上广泛表达的抗原 结肠癌、乳腺癌和肺癌。作为实现以下目标的第一步 为了达到这个目标，转基因人类CEA的小鼠已经准备好作为一种 癌胚抗原耐受性及启动或引入的影响 CEA免疫应答对正常组织功能和肿瘤的影响 成长。初步研究表明，关于组织 癌胚抗原表达的分布规律及其抗原耐受性 CEA转基因小鼠与人类非常相似。第一个目标是T细胞 对CEA的耐受性将在辅助性T细胞和细胞毒细胞中进行研究 车厢。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，延迟超敏反应测试将测量T细胞 响应性。对于第二个目标，B细胞对CEA的耐受性将是 检查过了。由辅助者非依赖性CEA结合物或 细胞因子融合蛋白将用于刺激抗体的形成。这个 诱导抗体的结合、效力和类别属性将是 下定决心。在第三个目标中，体液和细胞免疫的作用 对CEA在体内介导肿瘤细胞破坏的反应将是 用转CEA的同基因小鼠肿瘤进行分析。保护 在CEA免疫后将研究抗肿瘤生长- 与细菌佐剂一起表达成纤维细胞。可能的机制 将通过体内淋巴细胞耗尽和 过继转移和T细胞效应器活性的体外检测， 抗体的特异性和性质以及抗体依赖的细胞 细胞毒性。 将使用细胞疫苗或可溶性抗原进行免疫以偏向 对CEA的细胞或体液反应，以进一步剖析其作用 在调节肿瘤的破坏方面。作为上述目标的一部分，特殊性 相对于CEA交叉反应出现的抗CEA反应 抗原将被建立起来。对于最终目标，治疗性的 非转基因小鼠来源的抗CEA细胞毒T细胞的特性 将在领养转移后在转基因动物中进行研究。这 提出了采用治疗模式作为规避要求的一种手段 用于打破耐受性和控制可能的自身免疫反应。 这一目标下的研究将定义免疫优势CEA表位，使用 具有预测的I类结合基序的多肽或通过分离天然的 加工过的多肽。在所有研究中，可能出现的自身免疫性 伴随着抗CEA反应的反应将被描述。

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.