title: Differential Ia antigen expression by autologous human erythroid and B lymphoblastoid cell lines.
abstract: Human erythroid precursors express Ia antigens that have serology, function, molecular nature, and genetic regulation that are largely unknown. To approach these issues, Ia+ and Ia- subclones of the HEL human erythroleukemia cell line (HEL-DR+ and HEL-DR-, respectively) and an autologous B lymphoblastoid line (B line) were isolated. These erythroid and lymphoid lines were compared with respect to their binding of monoclonal HLA-D subregion-specific antibodies, the ability to trigger in vitro alloproliferation, expression of class II molecules, and transcription of class II-related genes. Unlike the DP+/DQ+/DR+ B lines, HEL-DR+ differentially expressed DP and DR, but not DQ specificities. Also unlike the autologous B line, HEL-DR+ appeared to be unable to trigger primary or secondary allogeneic T cell proliferation, despite the presence of responder monocytes in these cultures and irrespective of lymphokine addition. HEL-DR+ expression of bona fide class II molecules similar to B line DR heterodimers was verified by two-dimensional gel electrophoresis of material immunoprecipitated from 125I-labeled cells. Northern blot analysis of cytoplasmic RNA from these lines indicated that differential class II gene transcription could readily explain the distinct, lineage-related Ia phenotypes of HEL-DR+ and B line. In addition, the lack of invariant chain and class II transcripts in HEL-DR- implied that expression of these unlinked genes in HEL cells is co-regulated.
mesh_terms: D000937:Antigen-Antibody Reactions; D000954:Antigens, Surface / Q000032:analysis / Q000145:classification / Q000235:genetics; D001402:B-Lymphocytes / Q000276:immunology*; D002460:Cell Line; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II / Q000032:analysis* / Q000145:classification / Q000235:genetics; D006801:Humans; D004915:Leukemia, Erythroblastic, Acute / Q000235:genetics / Q000276:immunology*; D008213:Lymphocyte Activation; D010641:Phenotype; D011233:Precipitin Tests; D013601:T-Lymphocytes / Q000276:immunology; D014158:Transcription, Genetic
chemical_list: D000954:Antigens, Surface; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II