Patterns of reactivity of four novel monoclonal antibodies (B72.3, DF3, B1.1 and B6.2) with cells in human malignant and benign effusions.

The patterns of immunocytochemical reactivity produced in malignant and benign cells in effusions by staining with the monoclonal antibodies B72.3, DF3, B1.1 and B6.2 are reported. Using the mouse hybridoma methodology, these antibodies were raised against immunogens prepared from membrane-enriched extracts of metastatic carcinoma of the breast. Serial sections from the cell blocks of 20 benign effusions and 59 malignant effusions were incubated with the monoclonal antibodies using the avidin-biotin immunoperoxidase technique. The malignant neoplasms studied included specimens of 18 breast carcinomas, 12 ovarian carcinomas, 14 lung carcinomas, 7 leukemias/lymphomas and 8 miscellaneous malignant neoplasms. The monoclonal antibody B72.3 showed a positive staining reactivity with 36 of 39 adenocarcinomas (92%) versus staining in only 1 of 12 other neoplasms (8%). In contrast to the staining of adenocarcinomas, B72.3 stained no mesothelial cells in a total of 68 specimens tested. The monoclonal antibody DF3 showed a reaction pattern to neoplasms similar to that of B72.3 but also stained mesothelial cells in all of the specimens. The monoclonal antibodies B1.1 and B6.2 exhibited staining characteristics that have been associated with antibodies to carcinoembryonic antigen. The results of this study indicate that the monoclonal antibody B72.3 may function as a highly selective marker in recognizing a cancer cell versus a mesothelial cell and an adenocarcinoma cell versus other malignant tumor cells.