Expression of recombinant anti‐colorectal cancer large single‐chain monoclonal antibody in insect cells

Abstract

Colorectal cancer is the third most commonly diagnosed cancer in the world. Monoclonal antibody (mAb) CO17-1A recognizes the tumor-associated antigen GA733-2, a cell surface glycoprotein highly expressed in colorectal carcinoma cells which is applicable for preventing and curing colorectal cancer. In this study, we tried to produce a new recombinant anti-colorectal cancer large single chain (lsc) mAb based on mAb CO17-1A in the baculovirus-insect cell protein expression system. Two kinds of recombinant lsc mAbs were generated where variable light chain (VL) and heavy chain (HC) of mAb CO17-1A were fused together by an interchain linker. The only difference between the two mAbs is based on fusion of an ER retention signal (KDEL) at its C-terminus of HC. Polymerase chain reaction analysis verified the presence of both recombinant genes in the bacmid for generating viral expression vectors in insect cells. Western blot confirmed the expression of lsc mAbs in baculovirus-infected insect cells. Cell enzyme linked immunosorbent assay (ELISA) showed that the mAbs from cell lysates bound to SW480 and SW620 human colorectal cancer cells. These results indicate that the baculovirus insect expression system can produce anti-colorectal lsc mAb recognizing human colorectal cancer cells.