title: Differences in peptide presentation between B27 subtypes: the importance of the P1 side chain in maintaining high affinity peptide binding to B*2703.
abstract: Susceptibility to spondyloarthropathies is strongly associated with the MHC class I molecule HLA-B27, and is hypothesized to result from the presentation of arthritogenic peptides. Subtypes of B27 that differ structurally but are disease-associated ought to be capable of presenting such peptides, while nondisease-associated subtypes would not. We demonstrate that B*2703, the predominant West African B27 subtype that may not predispose to disease, is not recognized by most B*2705-alloreactive CTL, and does not efficiently present a known B*2705-restricted influenza A nucleoprotein (NP) peptide. We show inefficient presentation is due to a reduced binding affinity of B*2703 for the NP peptide. Furthermore, substituting Arg for the naturally occurring Ser at P1 of the NP peptide, restores high affinity binding and efficient presentation by B*2703. Our results suggest that B*2703 will bind and present efficiently only a subset of the peptides that bind to B*2705, in particular those with Arg or Lys at P1. The apparent lack of disease in individuals with B*2703 may be due to an inability to bind and present putative arthritogenic peptides.
authors.affiliation: Department of Microbiology and Immunology, University of North Carolina, Chapel Hill 27599-7290.
authors.forename: R A
authors.initials: RA
authors.lastname: Colbert
authors.forename: S L
authors.initials: SL
authors.lastname: Rowland-Jones
authors.forename: A J
authors.initials: AJ
authors.lastname: McMichael
authors.forename: J A
authors.initials: JA
authors.lastname: Frelinger
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D017951:Antigen Presentation; D001168:Arthritis / Q000235:genetics / Q000276:immunology; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D004247:DNA / Q000235:genetics; D015796:HLA-B27 Antigen / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D009980:Influenza A virus / Q000235:genetics / Q000276:immunology; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins / Q000235:genetics / Q000276:immunology; D010455:Peptides / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D011485:Protein Binding; D016601:RNA-Binding Proteins; D013122:Spinal Diseases / Q000235:genetics / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014758:Viral Core Proteins / Q000235:genetics / Q000276:immunology
chemical_list: D015796:HLA-B27 Antigen; C048842:NP protein, Influenza A virus; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; D010455:Peptides; D016601:RNA-Binding Proteins; D014758:Viral Core Proteins; D004247:DNA