Monoclonal antibodies to human colon and colorectal carcinoma

A series of monoclonal antibodies was produced by immunizing mice with fresh carcinoma of the colon and with the cell line HT-29. These antibodies could be classified into 3 different groups: (a) those which were HT-29 specific and reacted with no other cell line or fresh colon carcinoma samples; (b) antibodies which reacted with HT-29 and were also reactive with a number of other in vitro cell lines; and (c) antibodies which appeared to be specific for carcinoma of the colon cell lines in that they reacted selectively with colon carcinoma cell lines and not with carcinoma lines derived from other tissues. It was clearly shown by immunoperoxidase staining of both normal and neoplastic cells of the gastrointestinal mucosa, from stomach to colon, that these antibodies were not tumour-specific. Indeed, one antibody (250-30.6) has a remarkable specificity for secretory epithelium of any tissue whether it be found in the gastrointestinal tract, respiratory system or urinary system. We question the existence of tumour-specific antigens detected by monoclonal antisera described thus far, and comment on the remarkable specificity of some of the sera produced, emphasized by the secretory cell-specific antibody described herein.