title: 'Empty' Ld molecules capture peptides from endocytosed hepatitis B surface antigen particles for major histocompatibility complex class I-restricted presentation.
abstract: Peptides recognized by CD8+ cytotoxic T lymphocytes in the context of major histocompatibility complex (MHC) class I molecules are usually derived from endogenous proteins synthesized within the cell. Exogenous 22-nm hepatitis B surface antigen (HBsAg) particles are taken up by many cells, and are processed in a novel peptide-transporter-independent, endosomal or lysosomal pathway for class I (Ld)-restricted epitope presentation. Here, we present evidence that 'empty' Ld molecules derived from the cell surface are involved in presenting antigenic peptides from endocytosed HBsAg particles. Intracellular assembly of presentation-competent, trimeric Ld molecules required endocytosis of the exogenous antigen and 'empty' Ld molecules. These data assign a functional role to surface-associated, 'empty' MHC class I molecules.
authors.affiliation: Institute for Medical Microbiology and Immunology, University of Ulm, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Schirmbeck
authors.forename: J
authors.initials: J
authors.lastname: Reimann
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000235:genetics; D006183:H-2 Antigens / Q000235:genetics* / Q000378:metabolism*; D006514:Hepatitis B Surface Antigens / Q000276:immunology* / Q000378:metabolism; D064532:Histocompatibility Antigen H-2D; D006801:Humans; D006825:Hybridomas; D012515:Mast-Cell Sarcoma; D051379:Mice; D008810:Mice, Inbred C57BL; D010455:Peptides / Q000276:immunology* / Q000378:metabolism; D010587:Phagocytosis / Q000235:genetics / Q000276:immunology*; D014407:Tumor Cells, Cultured
chemical_list: D006183:H-2 Antigens; D006514:Hepatitis B Surface Antigens; D064532:Histocompatibility Antigen H-2D; D010455:Peptides