TUMOR CELL TARGETED IMMUNOGLOBULIN GENE THERAPY

该提案的总体目标是免疫调节肿瘤细胞， 用于治疗人类癌症的单克隆抗体（MAb）基因。 初步 研究表明，人结肠肿瘤细胞系可以产生 逆转录病毒介导的小鼠自身抗体转移 MAb基因，并且这些MAb基因转导的肿瘤细胞表现出改变 体内致瘤性。 由后者基因编码的单克隆抗体可以 参与NK/LAK细胞和巨噬细胞介导的抗体- 依赖性细胞介导的细胞毒性（ADCC）。 利用这些单克隆抗体基因- 转导的人结肠癌细胞系，第一个目标将确定 如果后者细胞以及混合的未转导的亲本肿瘤 细胞在ADCC测定中易被杀死。 致瘤 MAB基因转导的肿瘤细胞的性质将在无胸腺细胞中进行研究。 小鼠 转导肿瘤细胞致瘤性丧失的机制 将在具有抑制的NK细胞或巨噬细胞的无胸腺小鼠中进行评价 功能 对于第二个目标，基因工程单克隆抗体将是 其制备具有改善的表达和效应子功能性质。 将构建小鼠/人嵌合IgG 1 MAb以增强ADCC。 单链抗体的制备有助于单克隆抗体基因的转导 和表达。 为了确定FCR+细胞的局部靶向作用， 单克隆抗体在引起由MHC限制性细胞毒性介导的排斥反应中的作用 T细胞，第三个目标将制备可移植的，同基因小鼠 结肠肿瘤细胞表达人肿瘤抗原CEA和人肿瘤抗原CEA， ADCC介导的抗该抗原的抗体。 的致瘤性 细胞毒性MAb基因转导的鼠肿瘤细胞将在 同基因宿主及其引发对非- 将评估转导的亲本细胞。 这些研究将探讨 ADCC介导的抗体在促进免疫应答中的有效性 通过增强的抗原呈递和/或细胞因子产生CTL 通过效应细胞如巨噬细胞和NK细胞的释放， 在针对MAb基因转导的肿瘤细胞的ADCC反应中。 选择性 将通过转导来诱导针对外源抗原的CTL 与编码外源免疫球蛋白重链的基因同源的肿瘤 店 肿瘤细胞的保护和治疗特性 经遗传修饰以表达外来免疫球蛋白抗原的疫苗 将在携带未修饰的肿瘤细胞的动物中进行检查。 计划 这些研究将有望为人类提供一种新的免疫治疗方法， 基于MAb基因转导的能力的癌症治疗 肿瘤细胞疫苗诱导免疫应答， 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.