A monoclonal antibody directed against high M(r) salivary mucins recognizes the SO3-3Gal beta 1-3GlcNAc moiety of sulfo-Lewis(a): a histochemical survey of human and rat tissue

Using a panel of synthetic oligosaccharides attached to a polyacrylamide carrier, the epitope of monoclonal antibody F2, evoked to high M(r) salivary mucins, was mapped to the SO3-3Gal beta 1-3GlcNAc- moeity of the sulfo-Le(a) antigen. Using immunochemical techniques, the expression of the F2-epitope was investigated in a number of different isolated human mucin species, as well as in human and rat tissue specimens. The mAb F2 bound to high M(r) salivary mucins, cervical mucins, colon mucins and gallblader mucins, but not to low M(r) salivary mucins nor to gastric mucins. Immunohistochemical screening of human tissues with mAb F2 revealed a positive reaction with a number of epithelia, including the (sero)mucous salivary glands, the goblet cells of the colon, submucosal glands of the lung, the lining epithelium of cervical and esophageal glands, the suprabasal skin keratinocytes, and Hassall's corpuscles of the thymus. No staining was found in normal breast, pancreas, small intestine, spleen, and lymph nodes. Normal gastric glands were negative, but gastric intestinal metaplastic glands strongly stained with the antibody. In rat tissues, mAb F2 labeled epithelial cells of salivary glands, colon and stomach. In addition to epithelial cells, extracellular matrix components in rat thymus and skin were labeled by mAb F2. No labeling of erythrocytes, granulocytes, lymphocytes or bone marrow cells was found by FACScan analysis. The present data shows a tissue specific distribution of the F2-epitope in cells from the epithelial lineage in human and rat.