Effector Cell Analysis of Human Multidrug-resistant Cell Killing by Mouse-Human Chimeric Antibody against P-Glycoprotein

A mouse-human chimeric monoclonal antibody (mAb), MH162, against P-glycoprotein was previously found to be more effective than an all-mouse mAb (MRK16) in lysis of multidrug-resistant (MDR) tumor cells by blood mononuclear cells. The present study was performed to identify the effector cells responsible for the chimeric mAb-dependent cell-mediated cytotoxicity (ADCC) against MDR cells. The ADCC reaction was assessed by a 6-h ⁵¹Cr release assay. Highly purified lymphocytes (>99%), monocytes (>99%) and neutrophils (>96%) were obtained from peripheral blood of the same healthy donors. A comparison of these three effector cell populations showed no difference between MH162 and its all-murine counterpart MRK16 in MDR cell lysis by monocytes or neutrophils. But MH162 was more effective than MRK16 in lymphocyte-mediated lysis of the MDR cells. The lymphocytes responsible for this ADCC had CD16+ Fc receptors. Pretreatment of monocytes with colony-stimulating factors (IL-3, GM-CSF and M-CSF) caused significant increase in their MH162-mediated lysis of MDR cells. Another anti-P-glycoprotein chimeric mAb (MH171) was also more effective than its murine counterpart MRK17 in lymphocyte-mediated lysis of MDR cells. These findings suggest that mouse-human chimeric mAbs may be useful therapeutically for in vivo destruction of MDR cancer cells by the ADCC reaction.     

Specialized Localization of P-Glycoprotein Recognized by MRK 16 Monoclonal Antibody in Endothelial Cells of the Brain and the Spinal Cord

This communication describes the cellular and ultrastructural localization in the central nervous system of P-glycoprotein (P-GP) recognized by a murine monoclonal antibody, MRK 16. At the ultrastructural level P-GP was strictly confined to the luminal surface of the endothelial cells which comprise the capillary vessels of the brain and the spinal cord. No P-GP was found in the endothelial cells of other organs. Our findings may be useful as a means to define the blood-brain barrier, and they imply that the blood-brain barrier is anatomically characterized by the presence of intercellular tight junctions between continuous nonfenestrated endothelial cells.     

抗人胃癌3H11人-鼠嵌合抗体的构建及表达

为了降低抗人胃癌鼠单抗3H11的免疫原性,以利于该单抗在临床中的应用。我们构建并表达了3H11的人-鼠嵌合抗体,将3H11的轻、重链可变区基因分别插入到含有人k链及IgGl重链恒定区基因的真核细胞表达载体中,构建了3H11人-鼠嵌合抗体轻、重链表达载体。应用Lipofectin方法先将嵌合轻链表达载体转染到Sp2/0细胞中,经用含霉酚酸的选择培养基筛选及克隆化培养,获得稳定分泌3H11人-鼠嵌合轻链的转染细胞株。再将嵌合重链表达载体转染该细胞系,用含有组氨醇的选择培养基筛选,获得组氨醇抗性细胞株,经亚克隆后得到可稳定分泌人k链和人IgGl的转染细胞系,经ELISA检测该细胞系所分泌的上清含有可与人胃癌细胞系803结合的人IgG抗体活性,RT-PCR结果显示该细胞株有人-鼠嵌合抗体mRNA的转录,证明已获得分泌3H11人-鼠嵌合抗体的细胞系。     

Human Tumor Growth Suppression by Apoptosis Induced with Anti-ErbB-2 Chimeric Monoclonal Antibody

We established an anti-ErbB-2 mouse-human chimeric monoclonal antibody (MoAb), CH401, which was able to kill cancer cells overexpressing the ErbB-2 protein in vitro . The analysis of the killing mechanism indicated that MoAb CH401 might be the first anti-ErbB-2 mouse-human chimeric MoAb which can induce the apoptosis of cancer cells, since morphological changes and DNA fragmentation were recognized in MoAb CH401-treated cells. The ErbB-2 receptor appears to have two opposing functions: acting as a receptor both for a growth factor and for an apoptotic factor. Our results indicate that MoAb CH401 treatment may prove to be very useful for cancer therapy.