title: Functional consequence of variation in melanoma antigen expression.
abstract: Melanoma cells have been shown to express melanoma-associated antigens and, in many cases, the histocompatibility antigen, HLA-DR. We questioned whether the expression of these antigens was quantitatively altered during the serial passage of melanoma cells in culture. Therefore, we measured the binding of monoclonal antibodies specific for a melanoma-specific antigen and the HLA-DR antigen to melanoma cells from serial passages. Three cell lines were studied. We found that although both the melanoma-associated antigen and the HLA-DR antigen were qualitatively conserved, significant quantitative differences were seen. To study the functional consequences of these differences, we used fluorescence-activated cell sorting to create DR-enriched and DR-depleted populations from a single melanoma cell line heterogeneous for DR expression. We found that the proliferation of allogeneic T cells (measured by the 3H-TdR uptake) cultured with the DR-enriched and -depleted melanoma cell populations was directly related to the amount of the HLA-DR antigen expressed. These results indicate that in performance of experiments using melanoma cell lines quantitative assessment of antigenic expression is important, particularly if the function of a specific antigen is under examination. Further, our data clearly identify the HLA-DR antigen on melanoma cells as a participant in allogeneic lymphocyte stimulation.
mesh_terms: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm / Q000032:analysis*; D000954:Antigens, Surface / Q000032:analysis; D002469:Cell Separation; D002478:Cells, Cultured; D005434:Flow Cytometry; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D006801:Humans; D008213:Lymphocyte Activation; D008545:Melanoma / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II