title: Identification of immunodominant CD4+ T cell epitopes in patients with Yersinia-induced reactive arthritis by cytometric cytokine secretion assay.
abstract: OBJECTIVE
  In reactive arthritis (ReA), a bacteria-specific T cell response to the triggering microbe is detected in synovial fluid. So far, direct characterization of bacteria-specific T cells and identification of the immunodominant fine specificities remain difficult due to the lack of appropriate techniques. The aim of the present study was to directly determine the fine specificity of CD4+ T cells specific to ReA-associated bacteria-derived protein.
  
  
  METHODS
  In 2 patients with Yersinia-induced ReA, live Yersinia Hsp60-specific CD4+ T cells were directly isolated from synovial fluid after stimulation with Yersinia-derived protein Hsp60 using a cytometric cytokine secretion assay. Generated short-term T cell lines were then tested in vitro for their peptide epitope specificity. Also, direct cross-reactivity of one line with Chlamydia- and human-derived Hsp60 was assessed.
  
  
  RESULTS
  Generated short-term CD4+ T cell lines were highly antigen-specific and revealed single immunodominant peptide epitopes that were confirmed by direct testing with single peptides in both peripheral blood and synovial fluid cells. Yersinia Hsp60-specific T cells of one patient cross-reacted directly with human Hsp60.
  
  
  CONCLUSIONS
  Our results demonstrate the feasibility of direct assessment of live, potentially pathogenic, antigen-specific interferon-gamma+ CD4+ T cells taken from inflammatory lesions of patients with rheumatic diseases such as ReA. This might have implications not only regarding pathogenesis, but also in the design of new immunotherapies.
authors.affiliation: Deutsches Rheuma-Forschungszentrum, Berlin, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Thiel
authors.forename: Peihua
authors.initials: P
authors.lastname: Wu
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Lanowska
authors.forename: Jun
authors.initials: J
authors.lastname: Dong
authors.forename: Andreas
authors.initials: A
authors.lastname: Radbruch
authors.forename: Joachim
authors.initials: J
authors.lastname: Sieper
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D001170:Arthritis, Infectious / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism*; D018834:Chaperonin 60 / Q000235:genetics / Q000276:immunology*; D003429:Cross Reactions / Q000276:immunology; D018984:Epitopes, T-Lymphocyte / Q000378:metabolism*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D016056:Immunodominant Epitopes / Q000378:metabolism; D016130:Immunophenotyping; D007371:Interferon-gamma / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D008969:Molecular Sequence Data; D000091402:Prohibitins; D013583:Synovial Membrane / Q000166:cytology / Q000276:immunology; D015007:Yersinia / Q000235:genetics / Q000276:immunology*; D015009:Yersinia Infections / Q000150:complications* / Q000276:immunology
chemical_list: D018834:Chaperonin 60; D018984:Epitopes, T-Lymphocyte; D016056:Immunodominant Epitopes; D007376:Interleukin-2; C000717331:PHB2 protein, human; D000091402:Prohibitins; D007371:Interferon-gamma