Expression, glycosylation and function of recombinant anti‐colorectal cancer mAb CO17 ‐ 1A in SfSWT4 insect cells

Colorectal cancer is a commonly diagnosed cancer in the world. Monoclonal antibody ( mAb ) CO17 ‐ 1A recognizes the tumor‐associated antigen GA733 , a cell surface glycoprotein highly expressed in colorectal carcinoma cell, which is considered to be applicable for diagnosis and therapeutic treatment against colorectal cancer. In addition antibodies are glycoproteins, efficiently recognize and eliminate specific pathogenic and disease antigens. We have currently established baculovirus insect cell expression system to produce anti‐colorectal cancer mAb CO17 ‐ 1A . In this study, mAb CO17 ‐ 1A was expressed in the transgenic insect cell line SfSWT4 , in which glycosylation processing pathway has been humanized. Immunoblot confirmed that mAb CO17 ‐ 1A properly expressed in SfSWT4 insect cells. mAb CO17 ‐ 1A was purified using protein G affinity column. In addition, MALDI‐TOF verified that the mAb CO17 ‐ 1A fused to KDEL , endoplasmic reticulum ( ER ) retention signal ( mAb CO17 ‐ 1AK ) had high mannose type of glycan structure. Migration assay showed that insect cell‐derived mAb CO17 ‐ 1AK ( mAb I CO17 ‐ 1AK ) with high mannose type of glycan structure was effective as mammalian‐derived mAb CO17 ‐ 1A ( mAb M CO17 ‐ 1A ) in inhibition of metastasis. Kinetic analysis of antigen‐antibody interaction using Surface Plasmon Resonance ( SPR ) confirmed that mAb I CO17 ‐ 1AK is efficient to interact with antigen GA733 as mAb M CO17 ‐ 1A . These results suggest that the insect cell expression system with the SfSWT4 possibly can be used as a useful alternative way to produce full‐size mAb for cancer immunotherapy.