title: A measles virus glycoprotein-derived human CTL epitope is abundantly presented via the proteasomal-dependent MHC class I processing pathway.
abstract: Peptides derived from measles virus (MV) are presented by MHC class I molecules at widely divergent levels, but it is currently unknown how functional these levels are. Here, for the first time, we studied the natural occurrence and the underlying processing events of a known MV CTL epitope derived from the fusion glycoprotein (MV-F) and restricted via HLA-B*2705. Using MHC-peptide elution of MV-infected cells followed by sensitive mass spectrometry we determined the naturally occurring sequence to be RRYPDAVYL, corresponding to MV-F(438-446). Its level of expression was enumerated at approximately 1500 copies per cell, which is considered to be abundant, but lies within the range described for other viral CTL epitopes in human MHC class I molecules. We found that processing of the MV-F(438-446) epitope occurs primarily via the classic MHC class I loading pathway, since presentation to CTL depends on both the transporter associated with antigen presentation (TAP) and the proteasome. Even though it is cotranslationally inserted into the ER, a major part of MV-F is located in the cytosol, where it accumulates rapidly in the presence of proteasome inhibitors. We therefore conclude that a substantial cytosolic turnover of MV-F, together with some excellent processing features of MV-F(438-446) precursors, such as precise C-terminal excision by proteasomes, efficient TAP transport and strong HLA binding, dictate the abundant functional expression of the MV-F(438-446) CTL epitope in HLA-B*2705 at the surface of MV-infected cells.
authors.affiliation: Laboratory of Vaccine Research1, Laboratory of Organic Analytical Chemistry2, Laboratory of Pathology and Immunobiology3, National Institute of Public Health and the Environment, PO Box 1, 3720 BA Bilthoven, The Netherlands.
authors.forename: Carla A
authors.initials: CA
authors.lastname: Herberts
authors.affiliation: Laboratory of Vaccine Research1, Laboratory of Organic Analytical Chemistry2, Laboratory of Pathology and Immunobiology3, National Institute of Public Health and the Environment, PO Box 1, 3720 BA Bilthoven, The Netherlands.
authors.forename: Koert J
authors.initials: KJ
authors.lastname: Stittelaar
authors.affiliation: Laboratory of Vaccine Research1, Laboratory of Organic Analytical Chemistry2, Laboratory of Pathology and Immunobiology3, National Institute of Public Health and the Environment, PO Box 1, 3720 BA Bilthoven, The Netherlands.
authors.forename: Ed
authors.initials: E
authors.lastname: van der Heeft
authors.affiliation: Laboratory of Vaccine Research1, Laboratory of Organic Analytical Chemistry2, Laboratory of Pathology and Immunobiology3, National Institute of Public Health and the Environment, PO Box 1, 3720 BA Bilthoven, The Netherlands.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: van Gaans-van den Brink
authors.affiliation: Laboratory of Vaccine Research1, Laboratory of Organic Analytical Chemistry2, Laboratory of Pathology and Immunobiology3, National Institute of Public Health and the Environment, PO Box 1, 3720 BA Bilthoven, The Netherlands.
authors.forename: Martien C M
authors.initials: MCM
authors.lastname: Poelen
authors.affiliation: Laboratory of Vaccine Research1, Laboratory of Organic Analytical Chemistry2, Laboratory of Pathology and Immunobiology3, National Institute of Public Health and the Environment, PO Box 1, 3720 BA Bilthoven, The Netherlands.
authors.forename: Paul J M
authors.initials: PJM
authors.lastname: Roholl
authors.affiliation: Laboratory of Vaccine Research1, Laboratory of Organic Analytical Chemistry2, Laboratory of Pathology and Immunobiology3, National Institute of Public Health and the Environment, PO Box 1, 3720 BA Bilthoven, The Netherlands.
authors.forename: Loek J W
authors.initials: LJW
authors.lastname: van Alphen
authors.affiliation: Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands4.
authors.forename: Cornelis J M
authors.initials: CJM
authors.lastname: Melief
authors.affiliation: Laboratory of Vaccine Research1, Laboratory of Organic Analytical Chemistry2, Laboratory of Pathology and Immunobiology3, National Institute of Public Health and the Environment, PO Box 1, 3720 BA Bilthoven, The Netherlands.
authors.forename: Ad P J M
authors.initials: APJM
authors.lastname: de Jong
authors.affiliation: Laboratory of Vaccine Research1, Laboratory of Organic Analytical Chemistry2, Laboratory of Pathology and Immunobiology3, National Institute of Public Health and the Environment, PO Box 1, 3720 BA Bilthoven, The Netherlands.
authors.forename: Cécile A C M
authors.initials: CACM
authors.lastname: van Els
mesh_terms: D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D018528:ATP-Binding Cassette Transporters / Q000502:physiology; D000111:Acetylcysteine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000595:Amino Acid Sequence; D017951:Antigen Presentation; D003546:Cysteine Endopeptidases / Q000502:physiology*; D018984:Epitopes, T-Lymphocyte; D015395:Histocompatibility Antigens Class I / Q000378:metabolism*; D006801:Humans; D008459:Measles virus / Q000276:immunology*; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000502:physiology*; D046988:Proteasome Endopeptidase Complex; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D020298:U937 Cells; D014760:Viral Fusion Proteins / Q000276:immunology*
chemical_list: D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D018528:ATP-Binding Cassette Transporters; D018984:Epitopes, T-Lymphocyte; D015395:Histocompatibility Antigens Class I; D009097:Multienzyme Complexes; C073119:TAP1 protein, human; D014760:Viral Fusion Proteins; C067713:lactacystin; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D000111:Acetylcysteine