抗CD71人-鼠嵌合抗体的体外抗肿瘤效应及在肿瘤异种移植模型中的定位研究

Objective To investigate the anti-tumor effects in vitro and in vivo distribution of the human/murine chimeric antibody (D2C).Methods The CD71 positive target cells(K562,CEM and SMMC7721) and the effector cells ,freshly isolated human PBMC,with the ratio of target cells to effector cells 1:50,were incubated in various dilutions of D2C antibody(Ab).Antibody dependent cytotoxicity(AD-CC) was tested by using an LDH-release assay.Instead of effector cells,complement was added to the target cells (CEM,SMMC-7721) with various dilutions of D2C Ab.A method of counting death cells was used in complement dependent cytotoxicity(CDC) assay.Tumor localization and distribution of the chimeric antibody(D2C) were observed by labeling the chimeric Ab with radioiodine(^131I) and injecting in into nude mice(Balb/c nu/nu) transplanted with human hepatocellular carcinoma cells (SMMC-7721).Results A significant ADCC was observed with the increased concentration of the D2C Ab.Cytolysis of CD71-positive target cells by the D2C Ab was found in the presence of fresh rabbit complement.Labeled D2C administered by intraperitoneal as well as tumor regional in-jection,was visualized by SPECT. The distribution of D2C Ab in murine organs and tissues showed that non-specific binding was lower fol-lowing tumor regional administration than when the antibody was administered by an intraperitoneal injection.The human/murine chimeric antibody(D2C) has in vitro anti-tumor effects and can exert its effects in specific tumor localization.Its distribution and local effects in vi-vo can be detected by radioimmunoimaging. Conclusion CD71 human/murine chimeric antibody showed marked killing of tumor cells in vitro,and specific recognition and high affinity binding to tumor tissue in vivo.

The anti-tumor effects of an anti-CD71 chimeric antibody in vitro and its distribution in a tumor xenograft model

Objective To investigate the anti-tumor effects in vitro and in vivo distribution of the human/murine chimeric antibody (D2C). Methods The CD71 positive target cells (K562, CEM and SMMC7721) and the effector cells, freshly isolated human PBMC, with the ratio of target cells to effector cells 1∶50, were incubated in various dilutions of D2C antibody (Ab). Antibody dependent cytotoxicity (AD-CC) was tested by using an LDH-release assay. Instead of effector cells, complement was added to the target cells (CEM, SMMC-7721) with various dilutions of D2C Ab. A method of counting death cells was used in complement dependent cytotoxicity (CDC) assay. Tumor localization and distribution of the chimeric antibody (D2C) were observed by labeling the chimeric Ab with radioiodine (¹³¹I) and injecting it into nude mice (Balb/c nu/nu) transplanted with human hepatocellular carcinoma cells (SMMC-7721). Results A significant ADCC was observed with the increased concentration of the D2C Ab. Cytolysis of CD71-positive target cells by the D2C Ab was found in the presence of fresh rabbit complement. Labeled D2C administered by intraperitoneal as well as tumor regional injection, was visualized by SPECT. The distribution of D2C Ab in murine organs and tissues showed that non-specific binding was lower following tumor regional administration than when the antibody was administered by an intraperitoneal injection. The human/murine chimeric antibody (D2C) has in vitro anti-tumor effects and can exert its effects in specific tumor localization. Its distribution and local effects in vivo can be detected by radioimmunoimaging. Conclusion CD71 human/murine chimeric antibody showed marked killing of tumor cells in vitro, and specific recognition and high affinity binding to tumor tissue in vivo This project was supported by grant from the National Sciences Foundation of China (No. 39970693).