Mouse-human chimeric monoclonal antibody to carcinoembryonic antigen (CEA): in vitro and in vivo activities

Mouse-human chimeric antibody specific for human carcinoembryonic antigen (CEA) was produced by recombinant DNA techniques. The genes of the mouse variable regions of heavy and light chains were cloned from the mouse hybridoma, 2.7.1G.10., which secreted anti human CEA antibody (IgG1, kappa), and were joined with human gamma 1 and kappa constant genes. The affinity of the resultant chimeric antibody to its relevant antigen was the same as that of the parental mouse monoclonal antibody when analysed by Scatchard plot analysis. The chimeric antibody showed a potent antibody dependent cell-mediated cytotoxicity (ADCC) activity with human peripheral blood mononuclear cells against CEA-positive human adenocarcinoma cells. In vivo imaging analysis revealed that the present chimeric antibody was specifically localized on the tumor site. These results indicate that our mouse-human chimeric antibody is a promising reagent for the diagnosis and therapy of CEA-positive human cancers.