抗EGFR／抗CD3双功能抗体对胃癌荷瘤小鼠的免疫治疗研究

目的 通过抗EGFR／抗CD3双功能抗体（EGFR/CD3 BsAb）治疗SGC7901胃癌细胞移植瘤小鼠模型，初步验证该抗体在体内对胃癌细胞的杀伤能力。方法 采取化学偶联法合成的EGFR/CD3 BsAb联合人外周血淋巴细胞（PBLS）经尾静脉给药注入荷SGC7901胃癌细胞移植瘤小鼠体内。实验裸鼠随机分为抗EGFR单抗联合PBLS组（抗EGFR组）、抗CD3单抗联合PBLS组（抗CD3组）、EGFR／CD3 BsAb联合PBLS组（EGFR/CD3 BsAb组）和空白对照组（生理盐水组）。治疗后检测并比较加药各组对胃癌细胞的杀伤能力。结果 EGFR／CD3 BsAb成功制备，分子量为43kD。EGFR／CD3 BsAb组裸鼠的肿瘤抑制率为(57.2±8.6）％，显著高于抗EGFR组的（38.5±6.1）％和抗CD3组的（6.9±7.6）％（P＜0.05）；治疗结束时EGFR／CD3 BsAb组的瘤重为（517.1±45.4）mg，显著低于抗EGFR组的（737.4±54.3）mg和抗CD3组的（1097.9±167.7）mg（P＜0.05）。各组移植瘤组织EGFR免疫组化染色均为强阳性。EGFR／CD3 BsAb组裸鼠肿瘤组织CD3免疫组化染色可见部分细胞呈阳性。透射电镜观察显示，EGFR／CD3 BsAb组和抗EGFR组可见肿瘤坏死。结论 EGFR／CD3 BsAb在体内条件下可能对胃癌有治疗作用。

Immunotherapy of anti-CD3/anti-EGFR bispecific antibody on the mice borne human gastric cancer

Objective To investigate the effect of the immunotherapy mediated by anti-CD3/anti-EGFR bispecific antibody （BsAb） on the mice borne human gastric cancer and evaluate the effect of anti-CD3/anti-EGFR BsAb as a targeted therapeutic agent for gastric cancer. Methods The monoclonal antibody（mAb） of anti-CD3 and anti-EGFR were cross-linked to prepare the BsAb by chemical synthesis. The experimental therapy combined with PBLS as effector cells on the mice borne SGC7901 human gastric cancer was performed. Experimental mice were divided in to EGFR mAb group, CD3 mAb group, anti-CD3/anti-EGFR BsAb group and sa- line group. The comparisons of the curative activity among the anti-CD3/anti-EGFR BsAb, EGFR mAb and CD3 mAb groups were conducted in vivo. Results Anti-CD3/anti-EGFR BsAb was established successfully, and molecular weight was 43kD. The anti-tumor activity of the anti-CD3/anti-EGFR BsAb group was （57. 2 ± 8. 6） %, which was significantly higher than that in EGFR mAb group and CD3 mAb group （ P 〈 0. 05 ）. The EGFR immunohistochemical result of the transplanted tumor in each group was strong positive. There were some CD3 positive cells in the transplanted tumor tissues of the experimental group treated with anti-CD3/anti-EGFR BsAb. Necrocytosis in anti-CD3/anti-EGFR BsAb group and EGFR mAb group was detected by transmission electron microscope. Conclusion The anti-CD3/anti-EGFR BsAb has a powerful curative effect on gastric cancer in vivo.