HISTOCHEMICAL REACTIVITY OF NORMAL, METAPLASTIC AND NEOPLASTIC TISSUES TO ALPHA-LINKED N-ACETYLGLUCOSAMINE RESIDUE-SPECIFIC MONOCLONAL-ANTIBODY HIK1083

Monoclonal antibody (MAb) HIK1083, which is obtained by immunizing mic e with a preparation of rat gastric mucins, has been shown to bind spe cifically to alpha-linked N-acetylglucosamine (alpha-GlcNAc). We inves tigated the specificity of MAb HIK1083 by immunostaining normal human organs, mucinous metaplasia of human pancreas, adenocarcinomas of huma n stomach, pancreas, and colon, and normal rat organs. The specificity was investigated by making comparisons with (a) a stain that labels C lass III concanavalin A (ConA)-reactive mucin (Class III mucin), i.e., paradoxical ConA (PCS), and (b) staining with horseradish peroxidase (HRP)-conjugated Griffonia simplicifolia agglutinin II (GSA-II). In no rmal human and rat organs and in mucinous metaplasia of human pancreas , immunostaining with MAb HIK1083 and PCS showed similar specificities for mucins in glandular mucous cells. In adenocarcinoma of stomach an d pancreas, GSA-II showed the most widespread positivity, PCS showed t he least, and MAb HIK1083 showed a reactivity between those two extrem es. Colon adenocarcinomas were labeled only with GSA-II. These results demonstrate that MAb HIK1083 could be a useful screening tool for Cla ss III mucin in normal, metaplastic and carcinoma tissues, and that th e alpha-GlcNAc residue is one of the specific sugar residues found in Class III mucin.