Establishment of a murine monoclonal antibody against human clear cell carcinoma and analysis of the corresponding antigen.

Abstract A murine monoclonal antibody (Mab) 4B6, immunoglobulin M (IgM), λ chain, against human clear cell carcinoma of the ovary was established. Mab 4B6 reacted specifically to clear cell carcinomas, but failed to react to other types of ovarian carcinomas, such as mucinous, serous carcinoma, and also failed to react to human normal organ tissues. Mab 4B6 recognized antigenic determinants located on the membranes of carcinoma cells. Antigenic substances corresponding to Mab 4B6 were detected in sera of patients with ovarian clear cell carcinoma by using Sandwich radiometric assays performed with Mab 4B6-coated microplates and 125 I-Mab 4B6. Gel filtration on Sephacryl S-300 revealed that the antigen corresponding to Mab 4B6 possessed a molecular weight of 50 to 60 kDa. Furthermore, after periodic acid and enzyme treatments, it was suggested that the antigen epitope corresponding to Mab 4B6 contains a carbohydrate moiety.