title: The ins-and-outs of endosomal antigens for cross-presentation.
abstract: The efficiency of antigen cross-presentation, which is the presentation of extracellular antigens on MHC I molecules, critically depends on the stability of the internalized antigens. Since rapid degradation within the lysosomal compartment impairs cross-presentation, potent cross-presenting cells display several mechanisms to prevent activation of lysosomal proteases. Additionally, distinct endocytic receptors can target internalized antigens towards non-degradative early endosomes, from where efficient cross-presentation can occur. From these endosomes, antigens need to be processed for loading on MHC I molecules, which can occur by endo/lysosomal proteases or after translocation into the cytosol by the proteasome. Although the underlying mechanisms require further investigations, increasing evidence points out a decisive role of the ER-associated degradation machinery in such antigen translocation.
authors.affiliation: Life and Medical Sciences (LIMES) Institute, University of Bonn, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Schuette
authors.affiliation: Life and Medical Sciences (LIMES) Institute, University of Bonn, Germany. Electronic address: burgdorf@uni-bonn.de.
authors.forename: Sven
authors.initials: S
authors.lastname: Burgdorf
mesh_terms: D000818:Animals; D016827:CD8 Antigens / Q000276:immunology / Q000378:metabolism; D045142:Cross-Priming / Q000276:immunology*; D003713:Dendritic Cells / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D004705:Endocytosis / Q000276:immunology; D011992:Endosomes / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology; D005110:Extracellular Space / Q000276:immunology / Q000378:metabolism; D015395:Histocompatibility Antigens Class I / Q000276:immunology / Q000378:metabolism; D006801:Humans; D037181:Lectins, C-Type / Q000276:immunology / Q000378:metabolism; D009336:Necrosis; D055550:Protein Stability; D011971:Receptors, Immunologic / Q000276:immunology / Q000378:metabolism; D011975:Receptors, Mitogen / Q000276:immunology / Q000378:metabolism
chemical_list: D016827:CD8 Antigens; C409469:CD8 antigen, alpha chain; C530206:CLEC9a protein, human; C529914:Clec9a protein, mouse; D015395:Histocompatibility Antigens Class I; D037181:Lectins, C-Type; D011971:Receptors, Immunologic; D011975:Receptors, Mitogen