Production and characterization of rat monoclonal antibodies with an apparent specificity for certain lung cancers and their potential clinical application

This paper describes two rat monoclonal antibodies (MAbs) (1A6 and 2H7, both IgG2a) directed against a human adenocarcinoma of the lung (A549). Enzyme-linked immunosorbent assay (ELISA) and immunocytochemistry (Avidin-Biotin-complex method) as the screening of the hybridoma cells revealed that 1A6 and 2H7 MAb mainly reacted with adenocarcinoma of the lung, breast and pancreas, and 2H7 MAb also recognized large cell carcinoma, epithelia of the lung, trachea, tongue or small cell carcinoma of the lung. The antigen molecules recognized by 1A6 MAb was not detected by immunoprecipitation but the molecular size of the antigen by 2H7 was ca. 40Kd. The antibody-producing heterohybridoma cells could be transplanted into peritoneal cavities of nude mice to form ascites. We found these monoclonals useful for immunohistodiagnosis of surgical specimens from patients with lung cancer. Furthermore, we utilized 125I-labeled 2H7 MAb, aiming at localizing A549 tumor mass transplanted into nude mice subcutaneously. This antibody clearly localized the tumor mass. It is suggested that they may be useful as both diagnostic and therapeutic agents.