IMMUNOCYTOCHEMICAL REACTIVITY OF A MOUSE MONOCLONAL-ANTIBODY CDI315B RAISED AGAINST HUMAN BREAST-CARCINOMA

Our previous report revealed the production of monoclonal antibody (Mo Ab) CDI 315B by immunization of mice with tumor extract proteins of hu man invasive ductal breast carcinoma. In the present study we report o n the immunocytochemical reactivity of this MoAb with formalin or meth acarn fixed, paraffin embedded tissue sections and also with cell cult ures. Among breast tissues, positive staining was detected in 88% (64 of 73) of primary breast carcinomais, 77% (7 of 9) of metastatic lymph nodes, 24% (8 of 33) of benign breast disease and 15% (2 of 13) of no rmal breast tissue. No immunostaining was detected with several other tumors, with the exception of melanoma, where 63% (5 or 8) or positive staining was found. On in vitro cell lines, positive reaction was det ected only with breast carcinoma and melanoma cells, but not with othe r examined cell lines. On benign breast disease tissue sections, posit ive reaction was detected in areas with cell hyperplasia. On normal br east tissue sections MoAb 315B stained the epithelial cells of termina l ductuli. Since the MoAb 315B recognized some antigen present in the cytoplasm of most breast carcinoma cells, this MoAb may have potential application in diagnosis and management of breast cancer.