Expression and in vitro function of anti-cancer mAbs in transgenic Arabidopsis thaliana

The anti-colorectal cancer monoclonal antibody CO17-1A (mAb CO), which recognizes the tumor-associated antigen EpCAM, was expressed in transgenic Arabidopsis plants. PCR and western blot analyses showed the insertion and expression of heavy chain (HC)/HC fused to the KDEL ER retention modif (HCK) and light chain (LC) of mAb CO and mAb CO with HCK (mAb COK) in Arabidopsis transformants. Both plant-derived mAb^P CO and mAb^P COK were purified from a biomass of approximately 1,000 seedlings grown in a greenhouse. In sandwich ELISA, both mAb^P CO showed a slightly higher binding affinity for the target, EpCAM, compared to mAb^M CO. In cell ELISA, both mAbs^P COs showed binding affinity to the human colorectal cancer cell line SW480. Furthermore, mAb^M CO, mAb^P CO, and mAb^P COK exhibited dose and timedependent regression effects on SW480 cells in vitro. In summation, both mAb^P CO and mAb^P COK, expressed in Arabidopsis, recognized the target antigen EpCAM and showed anti-proliferative activity against human colorectal cancer cells.