Cutting edge: efficient MHC class I cross-presentation during early vaccinia infection requires the transfer of proteasomal intermediates between antigen donor and presenting cells.
Priming of CD8(+) T cells requires presentation of short peptides bound to MHC class I molecules of professional APCs. Cross-presentation is a mechanism whereby professional APC present on their own MHC class I molecules peptides derived from degradation of Ags synthesized by other Ag "donor cells." The mechanism of cross-presentation is poorly understood, and the nature of the transferred Ag is unknown. In this report, we demonstrate that the bulk of a cross-presented Ag transferred from donor cells recently infected with vaccinia virus are proteasomal products that are susceptible to peptidases within the donor cell cytosol and not full-length proteins or mature epitopes either free or bound to chaperones.
Serna
Amparo
A
Virology Working Group, Basic Science Division, Fox Chase Cancer Center, Philadelphia, PA 19111, USA.
Ramirez
Maria C
MC
Soukhanova
Anna
A
Sigal
Luis J
LJ
D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D000938:Antigen-Presenting Cells / Q000276:immunology* / Q000378:metabolism* / Q000821:virology; D000941:Antigens / Q000378:metabolism*; D002460:Cell Line; D002645:Chickens; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D003600:Cytosol / Q000276:immunology / Q000378:metabolism; D004527:Egg Proteins / Q000276:immunology / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000276:immunology / Q000378:metabolism; D006183:H-2 Antigens / Q000276:immunology / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D006825:Hybridomas; D016056:Immunodominant Epitopes / Q000276:immunology / Q000378:metabolism; D051379:Mice; D018832:Molecular Chaperones / Q000378:metabolism; D009097:Multienzyme Complexes / Q000378:metabolism*; D010047:Ovalbumin / Q000276:immunology / Q000378:metabolism; D010446:Peptide Fragments; D046988:Proteasome Endopeptidase Complex; D011485:Protein Binding / Q000276:immunology; D021381:Protein Transport / Q000276:immunology; D014616:Vaccinia virus / Q000276:immunology*
D000941:Antigens; D004527:Egg Proteins; D006183:H-2 Antigens; D016056:Immunodominant Epitopes; D018832:Molecular Chaperones; D009097:Multienzyme Complexes; C110366:OVA-8; D010446:Peptide Fragments; D010047:Ovalbumin; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex