title: A Novel HLA-DRB1*10:01-Restricted T Cell Epitope From Citrullinated Type II Collagen Relevant to Rheumatoid Arthritis.
abstract: Antibodies against citrullinated type II collagen (Cit-CII) are common in the sera and synovial fluid of patients with rheumatoid arthritis (RA); however, the known T cell epitope of CII is not dependent on citrullination. The aim of this study was to identify and functionally characterize the Cit-CII-restricted T cell epitopes that are relevant to RA.
  
  
  
  Peripheral blood mononuclear cells (PBMCs) from HLA-DRB1*10:01-positive patients with RA and healthy donors were stimulated in vitro with candidate CII peptides. CD154 up-regulation was measured as a marker of antigen-specific activation, and anti-HLA-DR-blocking experiments confirmed HLA restriction. Cytokine production was measured using a Luminex technique. Direct peptide-binding assays using HLA-DRB1*10:01 and HLA-DRB1*04:01 monomeric proteins were performed. The T cell receptor (TCR) β-chain of CD154-enriched antigen-specific T cells was analyzed using high-throughput sequencing.
  
  
  
  A novel Cit-CII peptide was identified based on its ability to activate CD4+ T cells from HLA-DRB1*10:01-positive individuals. When stimulated in vitro, Cit-CII autoreactive T cells produced proinflammatory cytokines. Cit-CII(311-325) bound (with low affinity) to HLA-DRB1*10:01 but not to HLA-DRB1*04:01, while the native form was unable to bind either protein. In addition, highly expanded clones were identified in the TCRβ repertoire of Cit-CII(311-325) -stimulated PBMCs.
  
  
  
  These results illustrate the ability of the citrullination process to create T cell epitopes from CII, a cartilage-restricted protein that is relevant to RA pathogenesis. The exclusive binding of Cit-CII(311-325) to HLA-DRB1*10:01 suggests that recognition of citrullinated epitopes might vary between individuals carrying different RA-associated HLA-DR molecules.
authors.affiliation: Karolinska University Hospital and Karolinska Institute, Stockholm, Sweden.
authors.forename: Karine
authors.initials: K
authors.lastname: Chemin
authors.affiliation: Amsterdam Rheumatology and Immunology Center, and Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Pollastro
authors.affiliation: Benaroya Research Institute at Virginia Mason, Seattle, Washington.
authors.forename: Eddie
authors.initials: E
authors.lastname: James
authors.affiliation: Karolinska Institute, Stockholm, Sweden.
authors.forename: Changrong
authors.initials: C
authors.lastname: Ge
authors.affiliation: Karolinska University Hospital and Karolinska Institute, Stockholm, Sweden.
authors.forename: Inka
authors.initials: I
authors.lastname: Albrecht
authors.affiliation: Karolinska University Hospital and Karolinska Institute, Stockholm, Sweden.
authors.forename: Jessica
authors.initials: J
authors.lastname: Herrath
authors.affiliation: Karolinska University Hospital and Karolinska Institute, Stockholm, Sweden.
authors.forename: Christina
authors.initials: C
authors.lastname: Gerstner
authors.affiliation: Uppsala University, Uppsala, Sweden.
authors.forename: Karolina
authors.initials: K
authors.lastname: Tandre
authors.affiliation: Amsterdam Rheumatology and Immunology Center, and Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Thais
authors.initials: T
authors.lastname: Sampaio Rizzi
authors.affiliation: Uppsala University, Uppsala, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Rönnblom
authors.affiliation: Karolinska University Hospital and Karolinska Institute, Stockholm, Sweden.
authors.forename: Anca
authors.initials: A
authors.lastname: Catrina
authors.affiliation: Karolinska Institute, Stockholm, Sweden.
authors.forename: Rikard
authors.initials: R
authors.lastname: Holmdahl
authors.affiliation: Karolinska University Hospital and Karolinska Institute, Stockholm, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Klareskog
authors.affiliation: Amsterdam Rheumatology and Immunology Center, and Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Niek
authors.initials: N
authors.lastname: de Vries
authors.affiliation: Karolinska University Hospital and Karolinska Institute, Stockholm, Sweden.
authors.forename: Vivianne
authors.initials: V
authors.lastname: Malmström
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D016022:Case-Control Studies; D002956:Citrulline / Q000276:immunology* / Q000378:metabolism; D024043:Collagen Type II / Q000276:immunology* / Q000378:metabolism; D016207:Cytokines / Q000276:immunology; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D005260:Female; D059811:HLA-DRB1 Chains / Q000276:immunology*; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D066298:In Vitro Techniques; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008297:Male; D008875:Middle Aged; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D024043:Collagen Type II; D016207:Cytokines; D018984:Epitopes, T-Lymphocyte; D059811:HLA-DRB1 Chains; C553505:HLA-DRB1*04:01 antigen; D016693:Receptors, Antigen, T-Cell, alpha-beta; D002956:Citrulline