单克隆抗体—表阿霉素免疫偶合物的制备和体外活性

用双功能试剂己二酰肼制备腙键连接的聚谷氨酸—表阿霉素,通过控制交联条件,所得产物克服了大分子自身交联的缺点,交联率较高。聚谷氨酸的载药量与分子量呈正比,平均每8～11个谷氨酸单体连接1分子表阿霉素。分子量为14300的聚谷氨酸做载体其载药量为1:11,与单抗交联所得的偶合物McAb:PGA:PAR为1:2:22。偶合物较好地保留了抗体活性,体外细胞毒性较游离药物略有下降,但表现出单抗介导的靶细胞选择性杀伤作用。本研究用腙键交联法成功地制备了药/抗比高且体外有效的免疫偶合物,为进一步制备细胞靶向的肿瘤化疗制剂奠定了基础。

PREPARATION AND IN VITRO ACTIVITY OF MONOCLONAL ANTIBODY-PHARMORUBICIN IMMUNOCONJUGATES

Bifunctional agent adipic dihydrate was used to form hydrazon bond between polyglutamic acid (PGA) and pharmorubicin (PAR). Under controlled condition, a relatively high rate of conjugation was obtained with no self-condensation. The value of PGA/PAR was in positive portion with the molecular weight (MW) of PGA∶ per 8～11 glutamic acid monomer linking one pharmorubicin. When PGA of MW 14 300 was used as carrier, the ratio of PGA/PAR was 1:11. After conjugating with anti-hepatoma monoclonal antiboty (McAb), an immunoconjugate of McAb:PGA:PAR being 1:2:22 was obtained. The immunoconjugate retained the binding activity to targeted cell compared with the purified and the oxidized antibody. Pharmacological studies in vitro showed lower cytotoxicity of the immunoconjugate than the free drug, but selective cytotoxicity directed by antibody was observed. Consequently, the immunoconjugate McAb-PGA-PAR with high ratio of drug/McAb as well as moderate targeting cytotoxity in vitro was successfully prepared. That makes it possible for the preparation of cell targeted drug which is expected to be benificial to tumor treatment.