Cell-surface antigens of human lung tumors detected by mouse monoclonal antibodies: definition of blood-group- and non-blood-group-related antigenic systems

Abstract

The pattern of antigen expression in human non-small-cell cancers of various histological subtypes has been studied. Mouse monoclonal antibodies (MAbs) were generated following immunizations with cell lines of squamous, adeno- and anaplastic large-cell carcinomas of the lung. Seven non-blood-group-related antigens were defined in addition to 5 antigens related to blood-group determinants. Detailed specificity was established with a large panel of cultured cell lines and normal and neoplastic tissues. MAb F-18 reacted in direct tests with the immunizing squamous lung carcinoma cell line, with 5 out of 5 choriocarcinoma cell lines, but with no other cell lines. No expression of F-18 antigen was observed in any normal or malignant tissue examined. The other 6 non-blood-group-reactive MAbs (F-7, F-8, F-11, F-15, F-16 and F-17) could be distinguished by their reactivity on a panel of cultured cells and tissues. One MAb in this group (F-17) reacted strongly with 19/35 lung tumor cell lines, 32/76 other tumor-derived cell lines, cultured normal kidney cells and fetal lung fibroblasts. This antibody did not react with any normal adult tissues examined, but did react with several cancer tissues including 1/17 lung tumors, 2/4 ovarian cancers and 1/5 colon tumors. Immunoprecipitation tests revealed that 5 of the antigens were glycoproteins: F-18 (Mr greater than 200,000), F-15 (Mr 44,000), F-16 (Mr 90,000), F-17 (Mr 95,000) and F-8 (Mr 95,000). Four MAbs detected Y blood-group antigen (Le(y)), only 2 of which were able to agglutinate O erythrocytes. Another antibody detected X blood-group antigen (Le(x)).