Selective association of a 22-38 kDa glycoprotein with MHC class II DP antigen on activated human lymphocytes at the plasma membrane.
Two-dimensional electrophoretic analysis (2D-PAGE) of cell surface human DP and DR class II antigens identified a glycoprotein, designated pX, that is associated at the cell surface with DP but not DR class II antigen in activated T, B and NK lymphocytes but not in resting B lymphocytes, Raji B lymphoma cells, activated thymic epithelial cells or activated monocytes. pX is a heavily glycosylated protein with an apparent molecular mass spanning between 38 kDa and 22 kDa, that is reduced, after deglycosylation with Endo-F, to 22 kDa. The pX structure appears nonpolymorphic and independent of DP polymorphism, as suggested by 2D-PAGE migrational pattern of 125I-labelled Endo-F deglycosylated DP immunoprecipitates from T cells blasts derived from four donors with different DP allotypes. The apparent absence of polymorphism of pX is further suggested by two-dimensional peptide mapping of a single spot derived from 2D-PAGE of 125I-labelled DP deglycosylated immunoprecipitates from two donors.
Carra
G
G
Istituto di Chimica Biologica, Università di Verona, Italy.
Giunta
M
M
Benati
C
C
Bovolenta
C
C
Tridente
G
G
Libonati
M
M
Gerosa
F
F
D001402:B-Lymphocytes / Q000737:chemistry / Q000276:immunology; D002478:Cells, Cultured; D006031:Glycosylation; D006682:HLA-DP Antigens / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D007399:Interphase / Q000276:immunology; D008213:Lymphocyte Activation; D016131:Lymphocyte Subsets / Q000737:chemistry / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D008970:Molecular Weight; D011485:Protein Binding / Q000276:immunology; D013601:T-Lymphocytes / Q000737:chemistry / Q000276:immunology
D006682:HLA-DP Antigens; D008562:Membrane Glycoproteins