title: Phagocytic processing of bacterial antigens for class I MHC presentation to T cells.
abstract: Class I major histocompatibility complex (MHC) molecules present antigens that are produced within the presenting cell or penetrate from the vacuolar system into the cytosol for processing. Most studies of exogenous antigen processing have used soluble antigens, which are not efficiently presented by class I MHC molecules and do not elicit CD8 T-cell responses in vivo. But particulate antigen preparations with no known mechanism for cytosolic penetration can also elicit CD8 T-cell responses in vivo. We report here that phagocytosis of bacteria with no mechanism for cytosolic penetration also results in presentation of bacterial antigens by class I MHC molecules. Moreover, this mechanism is resistant to cycloheximide and Brefeldin A, which block the classical class I processing pathway. These results suggest a novel vacuolar class I processing pathway for exogenous phagocytic antigens.
authors.affiliation: Department of Pathology, Washington University School of Medicine, St Louis, Missouri 63110.
authors.forename: J D
authors.initials: JD
authors.lastname: Pfeifer
authors.forename: M J
authors.initials: MJ
authors.lastname: Wick
authors.forename: R L
authors.initials: RL
authors.lastname: Roberts
authors.forename: K
authors.initials: K
authors.lastname: Findlay
authors.forename: S J
authors.initials: SJ
authors.lastname: Normark
authors.forename: C V
authors.initials: CV
authors.lastname: Harding
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D016827:CD8 Antigens / Q000276:immunology; D000939:Epitopes; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D015395:Histocompatibility Antigens Class I / Q000502:physiology*; D008264:Macrophages / Q000502:physiology / Q000648:ultrastructure; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D010047:Ovalbumin / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D010587:Phagocytosis; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012486:Salmonella typhimurium / Q000235:genetics; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D014617:Vacuoles / Q000502:physiology / Q000648:ultrastructure
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D016827:CD8 Antigens; D000939:Epitopes; D029968:Escherichia coli Proteins; D015395:Histocompatibility Antigens Class I; D011993:Recombinant Fusion Proteins; C489688:csgA protein, E coli; C077481:Crl protein, Bacteria; D010047:Ovalbumin