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.