title: Expression of aberrant HLA-B27 molecules is dependent on B27 dosage and peptide supply.
abstract: Cellular expression of non-classical forms of human leukocyte antigen (HLA)-B27 (NC-B27) may be involved in spondyloarthritis (SpA) pathogenesis. We used a novel B27-specific monoclonal antibody, HD6, to ask if B27 transgenic (TG) rat splenocytes express these NC-B27 molecules. We also investigated whether B27-binding peptides could affect the expression and functional immune recognition of HD6-reactive B27 molecules.
  
  
  
  Splenocytes from B27-TG, B7-TG and non-transgenic rats, and HLA-B27+ cell lines were stained with monoclonal antibodies recognising classical (ME-1, HLA-ABC-m1) and non-classical (HD6, HC10) B27. Cells were further cultured in the presence of HLA-B27-binding peptides, or subjected to brief low pH treatment prior to mAb staining and/or immunoprecipitation or co-culture with KIR3DL2-CD3ε-expressing Jurkat reporter cells.
  
  
  
  HD6-reactive molecules were detected in the majority of adult B27-TG rat splenocyte cell subsets, increasing with age and concomitant increased B27 expression. HD6 staining was inhibited by incubation with B27-binding peptides and induced by low pH treatment. HD6 staining correlated with KIR3DL2-CD3ε-expressing Jurkat reporter cell activity. Thus, IL-2 production was decreased when B27-expressing antigen-presenting cells were preincubated with B27-binding peptides, but increased following pretreatment with low pH buffer.
  
  
  
  Surface expression of HD6-reactive B27 molecules on B27-TG rat splenocytes is consistent with a pathogenic role for NC-B27 in SpA. Interaction of NC-B27 with innate immune receptors could be critical in SpA pathogenesis, and we show that this may be influenced by the availability and composition of the B27-binding peptide pool.
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Science, University of Oxford, , Oxford, UK.
authors.forename: Kirsty
authors.initials: K
authors.lastname: McHugh
authors.forename: Oliwia
authors.initials: O
authors.lastname: Rysnik
authors.forename: Simon
authors.initials: S
authors.lastname: Kollnberger
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Shaw
authors.forename: Lotta
authors.initials: L
authors.lastname: Utriainen
authors.forename: Mohammad Hussein
authors.initials: MH
authors.lastname: Al-Mossawi
authors.forename: Sravan
authors.initials: S
authors.lastname: Payeli
authors.forename: Osiris Marroquin
authors.initials: OM
authors.lastname: Belaunzaran
authors.forename: Simon
authors.initials: S
authors.lastname: Milling
authors.forename: Christoph
authors.initials: C
authors.lastname: Renner
authors.forename: Paul
authors.initials: P
authors.lastname: Bowness
mesh_terms: D000375:Aging / Q000276:immunology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000938:Antigen-Presenting Cells / Q000276:immunology; D002460:Cell Line; D018920:Coculture Techniques; D018628:Gene Dosage; D015796:HLA-B27 Antigen / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D019169:Jurkat Cells; D010455:Peptides / Q000378:metabolism*; D051381:Rats; D055647:Rats, Transgenic; D054347:Receptors, KIR3DL2 / Q000378:metabolism; D013154:Spleen / Q000166:cytology / Q000276:immunology*; D025241:Spondylarthritis / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D015796:HLA-B27 Antigen; C515084:KIR3DL2 protein, human; D010455:Peptides; D054347:Receptors, KIR3DL2