title: Cross-presentation of phage particle antigen in MHC class II and endoplasmic reticulum marker-positive compartments.
abstract: It has been shown that exogenous antigens can access the MHC class I pathway of professional antigen-processing cells. However, details as to how the MHC class I-peptide complex forms in the presentation pathway are still poorly understood. Here we used MHC class I-peptide-specific antibodies to investigate the formation and intracellular location of class I-peptide complexes in macrophages. We observed that the formation of class I-peptide complexes occurs within a few hours and lasts for another few hours on the cell surface of macrophages following loading with filamentous phage particles. The class I-peptide complexes in the process were co-localized with MHC class II molecules and endocytic system markers. Moreover, endosomal compartments containing class I-peptide complexes were found within intracellular organelles stained by DiOC6 and calnexin. In addition, the cross-presentation of phage particles was transporter associated with antigen processing (TAP)-dependent and sensitive to proteasome inhibitors and NH(4)Cl. These data suggest that endocytosed phage particles may be processed and cross-presented in organelles positive for phagosome and endoplasmic reticulum (ER) markers via a classical ER MHC class I loading mechanism.
authors.affiliation: The Institute of Immunology, PLA, The Third Military Medical University, Shapingba District, Chongqing, PR China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wan
authors.forename: Yuzhang
authors.initials: Y
authors.lastname: Wu
authors.forename: Jingran
authors.initials: J
authors.lastname: Zhou
authors.forename: Liyun
authors.initials: L
authors.lastname: Zou
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Liang
authors.forename: Jianping
authors.initials: J
authors.lastname: Zhao
authors.forename: Zhengcai
authors.initials: Z
authors.lastname: Jia
authors.forename: Jan
authors.initials: J
authors.lastname: Engberg
authors.forename: Jiang
authors.initials: J
authors.lastname: Bian
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
mesh_terms: D000643:Ammonium Chloride / Q000494:pharmacology; D000818:Animals; D000956:Antigens, Viral / Q000276:immunology*; D015415:Biomarkers / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D045142:Cross-Priming / Q000276:immunology*; D004721:Endoplasmic Reticulum / Q000276:immunology* / Q000378:metabolism; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000276:immunology* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D017912:Inovirus / Q000276:immunology*; D007700:Kinetics; D008074:Lipoproteins / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010587:Phagocytosis / Q000276:immunology; D061988:Proteasome Inhibitors; D015534:Trans-Activators / Q000378:metabolism; D022161:Transport Vesicles / Q000276:immunology; D014771:Virion / Q000276:immunology*
chemical_list: D000956:Antigens, Viral; D015415:Biomarkers; D002352:Carrier Proteins; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D008074:Lipoproteins; D061988:Proteasome Inhibitors; D015534:Trans-Activators; C500212:tocopherol-associated protein, mouse; D000643:Ammonium Chloride