title: An HLA-DR negative acute leukaemia which stimulates MLC and CMC responses.
abstract: We describe an acute myelomonocytic leukaemia (E72) devoid of cell-surface HLA-DR antigens, but capable of inducing cellular responses. Leukaemia E72 induced proliferation of normal lymphocytes in primary mixed lymphocyte culture (MLC), which was only weakly inhibited by anti-DR sera. Depletion of a small percentage (congruent to 4%) of DR+ cells on a cell-sorter failed to abrogate the capacity of E72 to stimulate MLC and cell-mediated cytotoxicity (CMC) responses. We found that normal lymphocytes primed with E72 responded in secondary MLC to lymphocytes and leukaemias, suggesting that the lymphocyte-activating determinant (LAD) on E72 is not leukaemia-specific. In addition, E72 induced CMC responses to both leukaemias and lymphocytes. We suggest that E72 may express a novel HLA or non-HLA LAD.
mesh_terms: D000368:Aged; D003602:Cytotoxicity, Immunologic; D005434:Flow Cytometry; D005802:Genes, MHC Class II; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D006650:Histocompatibility Testing; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000235:genetics / Q000276:immunology*; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D008297:Male
chemical_list: D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II