A
monoclonal antibody (2D11,
IgG2b) obtained by immunizing mice with a
mucin fraction of the human gastric mucosa reacted specifically to intestinal
metaplasia of human gastric mucosa and fetal intestinal mucosa but not to normal adult gastric, small intestinal or colonic mucosa in immunohistochemical staining. The results of Western blotting indicated that 2D11 recognized the high molecular weight
glycoprotein(s) (
mucin) of the stomach. Treatment of the
antigens with
sodium periodate abolished their reactivity to 2D11, and digestion of the
antigens with
beta-galactosidase reduced their reactivity to 2D11. Digestion of the
antigens with
pronase had no effect, however, suggesting that 2D11 recognizes the oligosugar moiety but not the
peptide moiety of the
antigens. Further immunohistochemical investigation showed that the reactivity of 2D11 was restricted to the Type IotaIotaIota intestinal
metaplasia that is identified by a characteristic staining pattern with the
high iron diamine-Alcian blue stain. 2D11 also reacted in high frequency to
adenocarcinomas of the stomach (66.7%), pancreas (66.7%) and gallbladder (50.0%), but in low frequency to those in lung (8.3%) and colon (11.1%). It is of interest that 2D11 reacted to very restricted regions of the gastric
adenocarcinomas. All
monoclonal antibodies to
mucin polypeptides (MUC1, 2, 3, 5AC and 6) examined stained intestinal
metaplasia and
carcinomas in a different pattern from 2D11 in immunohistochemistry. These facts indicate that Type IotaIotaIota intestinal
metaplasia and
carcinomas express
carbohydrate chains identical to those expressed in the fetal intestinal mucosa, suggesting that both of them are closely related to fetal intestinal mucosa.