CLONING AND SEQUENCING OF THE V-H AND V-K GENES OF AN ANTI-CD3 MONOCLONAL-ANTIBODY, AND CONSTRUCTION OF A MOUSE HUMAN CHIMERIC ANTIBODY/

Mouse monoclonal antibodies against CD3 on human T lymphocytes have be en used for therapy in organ-transplant patients as a potent immunosup pressive agent or for treatment of cancer as a potent T cell activatin g agent, However, an inherent problem in their in vivo application is the human anti-mouse antibody response, In this study, we cloned and s equenced the variable region genes of the heavy and light chains (V-H and V-k) of a mouse anti-human CD3 monoclonal antibody (OKT3) using th e reverse transcription-polymerase chain reaction method, Then, we con structed a mouse/human chimeric antibody, designated as Ch OKT3, by fu sing the OKT3 V-H and V-k genes to the human heavy and light chain con stant region genes (C gamma 1 and C-k) derived from a human plasma cel l leukemia line (ARH77), respectively, The chimeric gene constructs we re sequentially co-transfected into mouse non-Ig-producing hybridoma c ells (Sp2/0) by electroporation, The Ch OKT3 antibody thus prepared bo und to human peripheral blood mononuclear cells and competitively inhi bited the binding of the parental MAb OKT3 to the blood mononuclear ce lls, indicating that this chimeric antibody seems to be suitable for i n vivo therapeutic approaches.