HUMAN-HUMAN HYBRIDOMA PRODUCING MONOCLONAL-ANTIBODIES AGAINST COLORECTAL CANCER-ASSOCIATED ANTIGENS

Lymphocytes from lymph nodes draining the tumor region in patients with colorectal cancer were fused with two different human B-lymphoblastoid cell lines, LICR-LON-HMy-2 (HMy-2) and WI-L2-729-HF2 (729-HF2), to generate hybridomas synthesizing antibodies reacting with tumor-associated antigens. In this way 220 hybridomas were obtained which produce antibody reacting with colon cancer cells. All established clones produced IgM. Four human monoclonal antibodies have been further analyzed. The cell lines producing these antibodies are all hybrids based based on DNA analysis. Three of the antibodies (G4146, B9165 and D4213) showed binding to differentiation antigens by immunocytochemical analysis on different cancer cell lines and normal human leucocytes and by immunohistochemical analysis on sections of frozen malignant and normal tissues, while the fourth (F11348) showed a reaction with all cells and tissues tested. Western blots of tumor extracts showed binding of G4146 to two components from colon cancer cells with M(r) of 59 K and 61 K, while B9165 bound to a 43 K component and F11348 to several components with M(r) from 30 to 200 K. D4213 showed no binding in this analysis. The results obtained demonstrate the successful application of hybridoma technology to produce human monoclonals with reactivity to differentiation antigens.