Generation of human monoclonal antibodies recognising membranous antigens of the lung adenocarcinoma cell line A549 using an AMeX immunohistostaining method.

Four monoclonal antibodies (MAbs) from hybridoma obtained by in vitro stimulation of regional lymph node lymphocytes from lung cancer patients and electrofusion of the stimulated cells with murine or human-mouse myeloma cells were reactive to lung cancer cells in enzyme-linked immunoabsorbent assay, and to lung cancer tissue in immunohistochemical analysis using acetone-methyl benzoate-xylene (AMeX) fixed tissue and in immunofluorescence analysis. Three of the MAbs (designated ZLG40, 27D57 and 28K29) recognised cell-surface antigens of the lung adenocarcinoma cell line A549 and the remaining one (designated 29D38) recognised nuclear membrane antigens of the same cell line. The three surface-binding MAbs showed a significant complement-dependent cytotoxicity (CDC) to the A549 cells, but the membrane-binding 29D38 showed no CDC to the A549 cells. Western blotting of the extracts of the A549 or PC6 (small-cell lung cancer) cell lines by the four MAbs showed a 28K29 antigen band at M(r) of approximately 600,000 (+/- 2-ME), a ZLG40 antigen band at M(r) 50,000 (+/- 2-ME), and one 29D38 antigen band at M(r) of more than 1,000,000 (-2-ME) and M(r) between 20,000 and 80,000 (+2-ME), but no detectable band for 27D57 antigen.