Anti-cancer therapy for gastrointestinal canser using cytotoxic T cells and bispecific antibody

在抗CD3抗体存在的情况下，细胞毒性T淋巴细胞可以在体外杀伤Fc受体所在的靶细胞。重定向裂解不受主要组织相容性抗原的限制，也不需要CTL名义上的抗原识别。体内重定向裂解的有效性是通过比较接种了小鼠Fc受体基因的黑色素瘤细胞系与接种同基因小鼠CTL和抗CD3抗体的黑色素瘤小鼠的存活率来评估的。注射Fc受体阳性黑色素瘤、CTL和抗CD3单抗的动物存活率显著高于对照组。重定向裂解并不排除肿瘤免疫的建立，因为由于重定向裂解而排斥肿瘤的动物表现出对肿瘤细胞重新定位的抵抗力增加。过去几年的研究表明，在没有Ag和…的情况下，针对TcR或CD3的抗体可以激活细胞更多的d MHC基因产物。另一种利用CTL细胞毒潜力的天然方法是使用双特异性抗体来定向和激活不同特异性的CTL来溶解表达病毒或肿瘤抗原的细胞。针对TCR/CD3复合体和靶细胞表面抗原的双特异性抗体可以重定向CTL来裂解靶细胞。我们已经培育出一株杂交瘤，HHA6，它能分泌双特异性抗体，能够将CTL重定向到裂解流感病毒感染的靶细胞。当这些抗体与CTL一起加入到病毒感染的细胞中时，能非常有效地增强CTL的细胞毒能力。由于杂交瘤随机地重组了H链和L链，我们尝试用HPLC纯化双特异性抗体，纯化后提高了HHA6的效价。这增加和消除了抑制抗体的种类。根据这些实验结果，我们试图制造出分泌双特异性抗体的人杂交瘤，该杂交瘤能够重定向人CTL以杀伤人肿瘤细胞。由于人杂交瘤的不稳定性，我们没有成功地产生重定向人CTL以杀灭人靶细胞的人双特异性抗体。较少

Cytotoxic T lymphocytes can lyse Fc receptor-bearing target cells in vitro in the presence of anti-CD3 antibodies. This "redirected" lysis is not restricted by major histocompatibility antigen nor does it require nominal antigen recognition by the CTL.The efficacy of redirected lysis in vivo was assessed by comparing the survival of mice inoculated with a melanoma cell line transfected with the gene for mouse Fc receptor versus the untransfected melanoma when inoculated with syngenic mouse CTL and anti-CD3 antibody. Survival was significantly higher in the animals given injections of Fc receptor positive melanoma, CTL,and anti-CD3 monoclonal antibody. Redirected lysis does not preclude the establishment of tumor immunity, since animals that rejected the tumor as a result of redirected lysis exhibited an increased resistance to reinoculation with tumor cells.Studies over the last several years have demonstrated that antibodies to the TCR or CD3 can activate cells in the absence of Ag an … More d MHC gene products. An alter native approach to harnessing the cytotoxic potential of CTL can be to use bispecific antibodies to direct and activate CTL of various specificities to lyse cells expressing virus or tumor Ag. Bispecific antibodies with specificity for the TCR/CD3 complex as well as to a target cell-surface Ag can redirect CTL to lyse the target cell. We have produced a hybridhybridoma, HHA6, which secretes bispecific antibodies capable of redirecting CTL to lyse influenza virus-infected target cells. When added along with CTL to virus-infected cells, these antibodies very efficientlyenhace cytotoxic abilities of CTL.Because hybridhybridomas reassort H and L chains randomly we attempted to purify bispecific antibody by using HPLC.The purification increased the potency of HHA6. This increase and removal of inhibiting antibody species. From these experimental results, we have attempted to produce human hybridhybridoma which secretes bispecific antibodies capable of redircting human CTL to lyse human tumor cells.Because of unstableness of human hybridhybridoma, we have not succeeded in producing human bispecific antibodies redirected human CTL to destroy human target cells. Less