ACCUMULATION OF NCC-CO-411 MONOCLONAL-ANTIBODY IN HUMAN COLORECTAL ADENOCARCINOMA THROUGH BINDING OF THE RELEASED CARCINOEMBRYONIC ANTIGEN IN NUDE-MICE

NCC-CO-411, an anti-carcinoembryonic antigen (CEA) monoclonal antibody (MoAb) showed a dose-dependent reactivity with standard CEA, but did not bind to the CEA anchoring with cell membranes, When LS 174T cells, one of the CEA-producing cells, were treated with phosphatidylinosito l-specific phospholipase C, NCC-CO-411 MoAb recognized the released CE A containing glycosylphosphatidylinositol as well as the standard CEA. The binding activity of NCC-CO-411 MoAb with CEA was also demonstrate d by the immunostaining of the LS 174T colorectal tumor xenograft tiss ues, The biodistribution study showed that NCC-CO-411 MoAb was mainly taken up by tumor and kidney, while the anti-hCEA MoAb was largely con centrated in liver and spleen rather than in the tumor. These results suggest that NCC-CO-411 MoAb recognizes the released CEA and gives an excellent tumor image in LS 174T tumor-bearing mice.