Expression patterns of type II pneumocyte apical surface glycoconjugates in lung adenocarcinoma cells

Monoclonal antibodies and lectins were used to examine the expression patte rns of apical membrane oligosaccharide sequences specific to type II pneumo cytes in atypical adenomatous hyperplasia (AAH) and lung cancer. Atypical c ells of AAH and papillary adenocarcinoma cells expressed abundant sialyl Th omsen-Friedenrrich (TF) antigen: this was not observed in acinar adenocarci noma, bronchioloalveolar carcinoma with mucin production or squamous cell c arcinoma. Sialyl Tn antigens was also detected on a few cells in AAH and pa pillary adenocarcinomas. Asialo TF and Tn antigen were not observed on the surface of carcinoma cells of any type. Alpha(alpha)2,3-linked sialic acids predominated in type II pneumocyte, AAH and papillary adenocarcinoma, wher eas ciliated columnar cells expressed alpha 2,6-linked sialic acids. Lewis( x) and sialyl Lewis(x) antigens capped the TF antigen in both O- and N-link ed side chains on the surface of AAH and papillary adenocarcinoma cells, bu t were not expressed by type II pneumocytes. The findings demonstrate that papillary adenocarcinoma cells resemble type II pneumocytes in that they ex press abundant sialyl TF surface antigen, but they also express TF-related antigens not found in type II pneumocytes. Apical surface glycoconjugates o f AAH have structural characteristics shared by both type II pneumocytes an d papillary adenocarcinoma cells.