PEDS Advance Access published online on October 12, 2009
Protein Engineering Design and Selection, doi:10.1093/protein/gzp054
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Engineering and characterization of a baculovirus-expressed mouse/human chimeric antibody against transferrin receptor
1Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China 2Department of Laboratory Medicine and Technology, Hubei University of Chinese Medicine, Wuhan 430065, People's Republic of China 3 Institute of Biochemistry and Molecular Biology, Hubei University, Wuhan 430062, People's Republic of China
4 To whom correspondence should be addressed. E-mail: guanxin_shen{at}yahoo.com.cn
Transferrin receptor (TfR) has been explored as a target for antibody-based therapy of cancer. In the previous study, we reported a murine anti-TfR monoclonal antibody (mAb) 7579 had good anti-tumor activities in vitro. In an attempt to reduce its immunogenicity and enhance its ability to recruit immune effector mechanism in vivo, we herein developed its chimera in the baculovirus/insect cell expression system based on the mating-assisted genetically integrated cloning (MAGIC) strategy. The chimeric light and heavy chains, containing human IgG1 constant regions, were correctly processed and assembled in insect cells, and then secreted into the mediums as heterodimeric H2L2 immunoglobulins. Furthermore, analyses of antigen-binding assay and competitive binding assay indicated that the chimeric antibody possessed specificity and affinity similar to that of its parental murine antibody. Results of the antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) assay verified that the chimeric antibody could efficiently mediate ADCC and CDC against TfR-overexpressing tumor cells. These results suggested that this baculovirus-expressed chimeric anti-TfR IgG1 might have the potential to be used for cancer immunotherapy. Meanwhile, the MAGIC strategy, facilitating the rapid generation of chimeric mAbs, could be one of the efficient strategies for antibody engineering.
Keywords: antibody engineering/baculovirus-insect cell expression system/chimeric antibody/MAGIC/transferrin receptor
Received April 22, 2009; revised August 9, 2009; accepted August 10, 2009.