Humanized monoclonal antibody CAMPATH-1H: myeloma cell expression of genomic constructs, nucleotide sequence of cDNA constructs and comparison of effector mechanisms of myeloma and Chinese hamster ovary cell-derived material.

Expression of CAMPATH-1H, a humanized MoAb directed against an abundant surface antigen on human lymphocytes, has been studied using transfected myeloma cells. As the site of chromosome integration of DNA transfected into a cell is random we investigated the feasibility and frequency of hitting a 'jackpot' site for expression after co-transfection with CAMPATH-1H heavy and light chain constructs in genomic context. A cell line generating 40 micrograms/ml of CAMPATH-1H in spent culture supernatant was achieved. The full nucleotide sequence of the CAMPATH-1H heavy and light chain cDNA clones is also shown, in addition a comparison of the effector mechanisms, antibody dependent cellular cytotoxicity and complement dependent cytotoxicity, of myeloma cell and Chinese hamster ovary (CHO) cell-derived CAMPATH-1H is reported.