Production of human monoclonal antibody reactive with gastrointestinal carcinoma

Lymphocytes obtained from regional lymph nodes and spleen in the patients with gastrointestinal carcinoma were fused with the human B lymphoblastoid cell line GC01 and human hybridomas producing human monoclonal antibody (MoAb) were derived. Human MoAb No. 235 (IgM) derived from spleen cell of a gastric cancer patient reacted with adenocarcinoma of stomach, colon, and pancreas in the new immunohistochemical assay, modified direct immunoperoxidase method, and reacted with KATO III cells in cultured cell lines. The antigenic determinant of this antibody was suspected to be protein moiety after enzyme treatment. The competitive binding inhibition assay indicated that its epitope was different from anti-CEA monoclonal antibodies (KM10, A10, B9, AH3, JA4) and KM01. These findings suggested the possible use of human MoAb No. 235 for clinical application of targeting cancer chemotherapy in the future.