title: Assembly of an abundant endogenous major histocompatibility complex class II/peptide complex in class II compartments.
abstract: To identify the intracellular site(s) of formation of an endogenous class II/peptide complex in a human B cell line, we employed kinetic pulse-chase labeling experiments followed by subcellular fractionation by Percoll density gradient centrifugation and immunogold labeling on ultrathin cryosections. For direct demonstration of assembly of such complexes, we used the monoclonal antibody YAe, which detects an endogenous complex of the mouse class II molecule I-Ab with a 17-amino acid peptide derived from the alpha chain of HLA-DR (DR alpha52-68). We show that in human B lymphocytes, these class II/peptide complexes assemble and transiently accumulate in major histocompatibility complex class II-enriched compartments before reaching the cell surface.
authors.affiliation: Department of Immunology, University of Washington School of Medicine, Seattle 98195, USA.
authors.forename: S
authors.initials: S
authors.lastname: Morkowski
authors.forename: G
authors.initials: G
authors.lastname: Raposo
authors.forename: M
authors.initials: M
authors.lastname: Kleijimeer
authors.forename: H J
authors.initials: HJ
authors.lastname: Geuze
authors.forename: A Y
authors.initials: AY
authors.lastname: Rudensky
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000378:metabolism; D000944:Antigens, Differentiation, B-Lymphocyte / Q000378:metabolism; D001402:B-Lymphocytes / Q000378:metabolism* / Q000648:ultrastructure; D001692:Biological Transport; D002451:Cell Compartmentation; D002478:Cells, Cultured; D002499:Centrifugation, Density Gradient; D006681:HLA-D Antigens / Q000378:metabolism; D000949:Histocompatibility Antigens Class II / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D007700:Kinetics; D051907:Lysosomal Membrane Proteins; D046911:Macromolecular Substances; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D010455:Peptides / Q000276:immunology* / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D011994:Recombinant Proteins; D001619:beta-N-Acetylhexosaminidases / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; C416189:H2-M antigens; D006681:HLA-D Antigens; C084245:HLA-DM antigens; D000949:Histocompatibility Antigens Class II; D051907:Lysosomal Membrane Proteins; D046911:Macromolecular Substances; D008562:Membrane Glycoproteins; D010455:Peptides; D011994:Recombinant Proteins; C045084:invariant chain; D001619:beta-N-Acetylhexosaminidases