[Preparation and identification of monoclonal antibody against the gastric cancer cell line MGC 803].

Spleen cells of Balb/c mice, immunized with gastric cancer cell MGC 803, were fused with murine myeloma cell NS-1. After selective culture, screening and subcloning, a hybridoma PC1 which produced monoclonal antibody (McAb) against MGC 803 cells was obtained. McAb PC1 bound strongly with 3/4 gastric cancer and 1/2 hepatoma cell lines, weakly with another gastric cancer and 2/2 lung cancer cell lines, but did not bind with the autologous and allogenic lymphocytes, ABO red blood cells, human fetal lung fibroblasts and normal bone marrow cells. The binding capacity of McAb PC1 to MGC 803 decreased significantly due to the absorption by MGC 803 cells, but was not affected by lymphocytes and CEA. The corresponding antigen of McAb PC1 was expressed on the surface of MGC 803 cells. It may be a gastric cancer-associated antigen.