THE EXPRESSION OF H-LIKE BLOOD-GROUP GLYCOLIPIDS IN SMALL-CELL CARCINOMA OF THE LUNG

Monoclonal antibody SM1 has been shown to be preferentially reactive w ith small cell carcinoma of the lung (SCCL) cell lines by fluorescent and radioimmunoassay membrane staining (1). Using solid phase indirect radioimmunoassay, the antigen is not detected in non-SCCL lung carcin omas histologically classified as squamous carcinoma, adenocarcinoma o r large cell carcinoma , and other tumors,viz; pheochromocytoma, a mes oderm derived lymphoblastic leukemia cell line or in normal human brai n, heart, liver, colon, endothelial tissues of the aorta and blood ves sels, skin, omentum, muscle, lung parenchyma and is weakly reactive wi th bronchial mucosa, pancreas, and kidney. The membrane antigens detec ted by SM1 were isolated from small cell carcinoma of the lung (SCCL) cell line, SW2, using anion exchange chromatography and thin layer chr omatography, and were further analysed by exoglycosidase and endoglyco sidase treatments followed by chemical staining and immunostaining wit h SM1 and other antibodies. We show here that SM1 antibody reacts with a group of fucose-containing neutral glycolipids and gangliosides man y of which are cross-reactive with antibodies to H antigens.