Cell-cycle-dependent expression of human melanoma membrane antigen analyzed by flow cytometry.
Knowledge of tumor antigenic expression is crucial to the design of therapeutic strategy. A murine monoclonal antibody (BE4) against a human melanoma membrane antigen, was used to study the in vitro expression of this antigen. By membrane immunofluorescence, BE4 reacted against 5 of 8 melanoma lines as compared to zero of 13 other cell populations. Using flow cytometry, the antigenic M14 CEM melanoma cells consisted of 40% to 60% of the total cell population. Dual-parameter measurements of DNA content and membrane antigen demonstrated that the nonantigenic cells were predominantly in G0/G1 phase, whereas the antigenic cells were distributed throughout the cell cycle. Within one passage, the sorted and recultured nonantigenic population demonstrated a similar proportion of antigenic cells as the unsorted original population. It was concluded that the expression of human melanoma antigen was cell-cycle-dependent. Understanding factors that turn off the expression of antigen in G0/G1 phase may lead to better immunotherapeutic strategies.
D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000276:immunology; D000951:Antigens, Neoplasm / Q000032:analysis*; D000954:Antigens, Surface / Q000032:analysis*; D001386:Azides; D002453:Cell Cycle; D002460:Cell Line; D004247:DNA / Q000032:analysis; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006801:Humans; D007621:Karyotyping; D008545:Melanoma / Q000276:immunology*; D019810:Sodium Azide; D014357:Trypsin
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D001386:Azides; D004247:DNA; D019810:Sodium Azide; D014357:Trypsin