[Monoclonal antibody 9A3 raised against a human poorly differentiated gastric adenocarcinoma cell line].

A new mouse monoclonal antibody 9A3 (IgGl,K) raised against human poorly differentiated gastric adenocarcinoma cell line TMK-1 was produced. Immunohistochemically, 9A3 antibody reacted strongly with gastric carcinoma, colon carcinoma, pancreas carcinoma, lung carcinoma, breast carcinoma and cervical carcinoma of the uterus. This antibody did not react with various normal tissues from the whole body with the exception of neutrophils and macrophages. In fetal tissues, 9A3 antibody reacted with esophageal mucosa and colon epithelium, but did not react with purified carcinoembryonic antigen (CEA). The molecular weight of the antigen extracted with NP-40 from TMK-1 cells was estimated to be about 46,000 daltons by SDS-PAGE. The 9A3 antigen was also detected in conditioned tissue culture medium of the TMK-1 cell line and sera of gastric cancer patients and tumor imaging could be performed in xenotransplantable human gastric carcinoma in nude mice. In summary, 9A3 antibody may serve as a new marker for detection of cancer by immunohistochemical, cytological techniques and serologically in the sera of cancer patients.