GENE THERAPY WITH MAB DRIVATIVES EXPRESSED ON TUMORS

描述：(申请人摘要)申请人实验室以前的工作 已经证明，共刺激在诱导一种 免疫反应，包括对肿瘤的免疫反应。这种共刺激作用可以通过以下方式提供 将编码配体的基因(如CD80和/或CD86)导入 肿瘤细胞，或通过转染编码单链抗体(ScFv)的基因 选择合适的抗受体单抗。ScFv方法的优势在于 天然配基的使用。例如，CD80和CD86具有很高的亲和力 对CTLA-4产生强烈的负面信号，而抗CD28单链抗体 不会的。此外，单链抗体可以在天然配体未知的情况下使用，如 至于CD3-epsilon。在本应用中，杂交瘤的可变区基因 针对人类共刺激受体的抗体将被表达为细胞 表面单链抗体可调节针对肿瘤细胞的抗原特异性免疫反应。 编码单链抗体的基因保持了特异性和高结合亲和力 构建并表达了CD3-epsilon、CD28、CD2、CD4、CD8和CD154 作为可溶性Ig融合蛋白。跨膜结构域已经被添加到一些 ScFv基因构建将其表达定向到细胞表面。这些 基因将在人类肿瘤细胞系表面表达以确定 它们扩增T细胞反应的潜力。申请人 假设使用抗体衍生物可以提高特异性和 肿瘤基因治疗的效力，以及单链抗体的细胞表面表达将 与表达相比增强对特定抗原的免疫应答 T细胞表面受体的天然配体。他将决定是否 T细胞刺激分子和共刺激分子特异性单链抗体的表达 在肿瘤细胞表面会增加T细胞的激活，包括 CD4+Th1反应和CD8+细胞毒反应对肿瘤排斥反应具有重要意义。

DESCRIPTION: (Applicant's Abstract) Previous work in the applicant's laboratory has demonstrated that costimulation plays a key role in the induction of an immune response, including one to tumors. This costimulation can be provided by either transfecting a gene encoding a ligand, such as CD80 and/or CD86 into tumor cells, or by transfecting a gene encoding a single chain Fv (scFv) from the appropriate anti-receptor mAb. The scFv approach can have an advantage over the use of natural ligands. For example, CD80 and CD86 bind with high avidity to CTLA-4, which produces a strong negative signal, while the anti-CD28 scFv does not. In addition, scFvs can be used when natural ligands are unknown, such as for CD3-epsilon. In this application, variable region genes from hybridoma antibodies specific for human costimulatory receptors will be expressed as cell surface scFvs to modulate antigen-specific immune responses to tumor cells. Genes encoding scFvs that retain specificity and high binding affinity for CD3-epsilon, CD28, CD2, CD4, CD8, and CD154 have been constructed and expressed as soluble Ig-fusion proteins. Transmembrane domains have been added to some of the scFv gene constructs to direct their expression to the cell surface. These genes will be expressed on the surface of human tumor cell lines to determine their potential for amplification of T cell responses. The applicant hypothesizes that use of antibody derivatives can improve the specificity and potency of cancer gene therapy, and that cell surface expression of scFvs will enhance the immune response to specific antigens when compared with expression of native ligands for T cell surface receptors. He will determine whether expression of scFvs specific for T cell stimulatory and costimulatory molecules on the surface of tumor cells will increase T cell activation, including both CD4+ Th1 responses and CD8+ cytotoxic responses important for tumor rejection.