HLA-B27 presents a peptide from a polymorphic region of its own molecule with homology to proteins from arthritogenic bacteria.
A possible mechanism for the pathogenesis of HLA-B27-associated spondyloarthropathies is that peptides from arthritogenic bacteria with homology to endogenous self-peptides presented by HLA-B27, including those derived from HLA-B27 itself, could elicit an autoimmune T-cell response upon infection. We report here that an undecamer corresponding to the polymorphic region of HLA-B27 spanning residues 169-179 is presented in vivo by the B*2701, B*2704 and B*2706 subtypes, but was not detected in the B*2703-bound peptide pool. This peptide binds to B*2705 in vitro with sufficient affinity to allow its natural presentation by this subtype, but it binds with low affinity to B*2703. In spite of homology of this peptide to proteins from arthritogenic bacteria, its binding specificity does not correlate with current evidence concerning association of HLA-B27 subtypes to ankylosing spondylitis, suggesting that presentation of this peptide is not the critical feature that determines linkage of HLA-B27 to this disease.
García
F
F
Centro de Biologia Molecular Severo Ochoa (C.S.I.C.-U.A.M.), Universidad Autónoma de Madrid, Facultad de Ciencias, Spain.
Marina
A
A
Albar
J P
JP
López de Castro
J A
JA
D000818:Animals; D017951:Antigen Presentation; D001170:Arthritis, Infectious / Q000276:immunology / Q000382:microbiology*; D001426:Bacterial Proteins / Q000276:immunology*; D002460:Cell Line; D015796:HLA-B27 Antigen / Q000276:immunology*; D006801:Humans; D051379:Mice; D010446:Peptide Fragments; D011110:Polymorphism, Genetic; D017386:Sequence Homology, Amino Acid; D013167:Spondylitis, Ankylosing / Q000276:immunology; D014407:Tumor Cells, Cultured
D001426:Bacterial Proteins; D015796:HLA-B27 Antigen; D010446:Peptide Fragments