title: Lack of expression of HLA-ABC antigens in choriocarcinoma and other human tumor cell lines.
abstract: We studied a panel of 21 human tumor and other cell lines, mainly of epithelial origin, for the expression of HLA-ABC antigens by an indirect radiobinding assay using monoclonal antibodies. Four of the lines, 2 choriocarcinomas, a breast tumor cell lin (MDA-MB-157), and a colon carcinoma (LoVo) showed no detectable reaction with the antibodies. The levels of binding in another breast tumor line (SkBr3) and a colon carcinoma line (LS174T) were much reduced. These cell lines plus some of the HLA-ABC positive lines from the panel were studied by immunoprecipitation of 35S-labeled cell extracts. Two mechanisms for alteration of the HLA-ABC antigen levels at the cell surface were apparent. In the choriocarcinomas and one breast tumor line, beta 2 microglobulin (beta 2m) was expressed but little or no HLA-A, B, or C polypeptides were synthesized. The other HLA-ABC negative lines had defects similar to that in the previously reported Burkitt's lymphoma cell line DAUDI. In these lines, HLA-ABC polypeptides were produced but did not appear at the cell surface because beta 2m was not synthesized. The absence of HLA-ABC determinants from the cell surface is presumed to afford protection against T-cell immune attack whether naturally as against the trophoblast during pregnancy or in abnormal situations against certain tumors.
mesh_terms: D000911:Antibodies, Monoclonal; D001943:Breast Neoplasms / Q000276:immunology; D002460:Cell Line; D002478:Cells, Cultured; D002822:Choriocarcinoma / Q000276:immunology*; D003110:Colonic Neoplasms / Q000276:immunology; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes; D005260:Female; D006680:HLA Antigens / Q000032:analysis*; D015235:HLA-B Antigens; D015236:HLA-C Antigens; D006801:Humans; D066298:In Vitro Techniques; D009369:Neoplasms / Q000276:immunology*; D011247:Pregnancy; D014594:Uterine Neoplasms / Q000276:immunology*; D001613:beta 2-Microglobulin / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D006680:HLA Antigens; D015235:HLA-B Antigens; D015236:HLA-C Antigens; D001613:beta 2-Microglobulin