Identification of hairy cell leukemia subset defining p35 as the human homologue of Ii.
A molecule defining a subset of patients with hairy cell leukemia (HCL) on the basis of being abundantly labeled with [35S]methionine, was demonstrated to be the human homologue of murine Ii, a glycoprotein which lacks alloantigenic variation and is associated non-covalently with Ia antigens. In one-dimensional SDS-polyacrylamide gradient gel electrophoresis, the HCL-subset-defining molecule migrated with HLA-DR molecules which were immunoprecipitated with a specific heteroantiserum. These molecules were further defined in two-dimensional, SDS and non-equilibrium pH gradient electrophoresis of either membrane preparations or immunoprecipitates formed with various antibodies. [35S]methionine-labeling of the HCL-subset-defining molecule was greater in hairy leukemic cells than in lymphoblastoid cell lines. The subset-defining species was associated non-covalently with HLA-DR alpha and beta chains and ran electrophoretically at a position described for murine and human Ii molecules (in terms of pI and weight). Metabolic labeling of HLA-A,-B and -DR was also increased in HCL cells relative to lymphoblastoid cell lines. A separate protein, of 41,000 mol. wt and pI of 7-8, resembled another Ii-associated molecule which has been described in murine and human studies.
D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II / Q000032:analysis*; D006801:Humans; D007526:Isoelectric Point; D007943:Leukemia, Hairy Cell / Q000378:metabolism*; D008565:Membrane Proteins / Q000032:analysis; D008970:Molecular Weight; D009363:Neoplasm Proteins / Q000032:analysis*
D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; D008565:Membrane Proteins; D009363:Neoplasm Proteins