TUMOR CELL TARGETED IMMUNOGLOBULIN GENE THERAPY

这项提议的总体目标是通过免疫调节肿瘤细胞 单抗(MAb)基因用于治疗人类癌症。初步 研究表明，人类结肠肿瘤细胞系可以产生 逆转录病毒介导的小鼠自身反应性抗体转移 单抗基因，这些单抗基因转导的肿瘤细胞表现出改变 体内致瘤性。后一种基因编码的单抗可以 与NK/LAK细胞和巨噬细胞共同参与介导抗体- 依赖细胞介导的细胞毒作用(ADCC)。利用这些单抗基因- 转导人结肠癌细胞株的第一个目标将确定 如果后者的细胞以及混合的非转导亲本肿瘤 在ADCC检测中，细胞对杀伤很敏感。致癌因素 转导MAB基因的肿瘤细胞的特性将在无性系中进行研究 老鼠。转导肿瘤细胞致瘤性丧失的机制 将在NK细胞或巨噬细胞受到抑制的裸鼠身上进行评估 功能。对于第二个目标，转基因单抗将是 制备了具有改进的表达和效应器功能特性的产品。 将构建鼠/人嵌合IgG1单抗以增强ADCC。 将制备单链抗体以促进单链抗体基因转导 和表情。确定局部靶向FCR+细胞的作用 单抗在MHC限制性细胞毒介导的排斥反应中的作用 T细胞，第三个目标是制备可移植的同基因小鼠 结肠肿瘤细胞同时表达人类肿瘤抗原CEA和 ADCC介导的针对该抗原的抗体。肿瘤的致瘤性 转导细胞毒性单抗基因的小鼠肿瘤细胞将在 同基因宿主及其对非霍乱病毒的保护能力 将对转导的亲本细胞进行评估。这些研究将探索 ADCC介导型抗体在促进小鼠胸腺发育中的作用 通过增强抗原提呈和/或细胞因子发展CTL 巨噬细胞和NK细胞等效应细胞参与释放 在抗单抗基因转导肿瘤细胞的ADCC反应中。有选择性的 针对外来抗原的CTL的诱导将通过转导进行 编码外源免疫球蛋白重链基因的同基因肿瘤 锁链。肿瘤细胞的保护和治疗特性 表达外源免疫球蛋白抗原的转基因疫苗 将在携带未经修饰的肿瘤细胞的动物身上进行检测。计划中的 研究将有望导致一种新的免疫治疗方法 基于转导单抗基因的能力的癌症治疗 肿瘤细胞疫苗诱导弱免疫应答的实验研究 肿瘤细胞特有的天然抗原。

The overall goal of this proposal is to immunomodulate tumor cells with monoclonal antibody (MAb) genes for therapy of human cancer. Preliminary studies have demonstrated that a human colon tumor cell line can produce self-reactive antibody following retrovirus-mediated transfer of murine MAb genes, and that these MAb gene-transduced tumor cells display altered tumorigenicity in vivo. The MAb encoded by the latter genes can participate with NK/LAK cells and macrophages in mediating antibody- dependent cell mediated cytotoxicity (ADCC). Using these MAb gene- transduced human colon carcinoma cell lines, the first aim will determine if the latter cells as well as admixed non-transduced parental tumor cells are susceptible to killing in assays of ADCC. The tumorigenic properties of MAB-gene transduced tumor cells will be studied in athymic mice. The mechanisms for loss of transduced tumor cell tumorigenicity will be evaluated in athymic mice having suppressed NK cell or macrophage function. For the second aim, genetically engineered MAbs will be prepared having improved expression and effector function properties. Mouse/human chimeric IgG1 MAbs will be constructed to enhance ADCC. Single chain Fv MAbs will be prepared to facilitate MAb gene-transduction and expression. To determine the role that local targeting of FCR+ cells by MAbs has in provoking rejection mediated by MHC-restricted cytotoxic T-cells, the third aim will prepare transplantable, syngeneic murine colon tumor cells that express both a human tumor antigen, CEA, and an ADCC-mediating antibody against this antigen. The tumorigenicity of the cytotoxic MAb gene-transduced murine tumor cells will be studied in syngeneic hosts and their ability to elicit protection against non- transduced parental cells will be evaluated. These studies will explore the effectiveness of an ADCC-mediating antibody in promoting the development of CTLs through enhanced antigen presentation and/or cytokine release by effector cells such as macrophages and NK cells participating in ADCC reactions against MAb gene-transduced tumor cells. Selective induction of CTLs against alien antigens will be pursued by transduction of syngeneic tumors with genes encoding for foreign immunoglobulin heavy chains. The protective and therapeutic properties of a tumor cell vaccine genetically modified to express alien immunoglobulin antigens will be examined in animals bearing unmodified tumors cells. The planned studies will hopefully lead to a new immunotherapeutic approach for the treatment of cancer that is based on the ability of a MAb gene-transduced tumor cell vaccine to induce immunological responses against weak antigens that are unique and native to the tumor cell.