title: Altered peptide ligands inhibit arthritis induced by glucose-6-phosphate isomerase peptide.
abstract: BACKGROUND
  Immunosuppressants, including anti-TNFalpha antibodies, have remarkable effects in rheumatoid arthritis; however, they increase infectious events. The present study was designed to examine the effects and immunological change of action of altered peptide ligands (APLs) on glucose-6-phosphate isomerase (GPI) peptide-induced arthritis.
  
  
  METHODS
  DBA/1 mice were immunized with hGPI325-339, and cells of draining lymph node (DLN) were stimulated with hGPI325-339 to investigate the T-cell receptor (TCR) repertoire of antigen-specific CD4+ T cells by flow cytometry. Twenty types of APLs with one amino acid substitution at a TCR contact site of hGPI325-339 were synthesized. CD4+ T cells primed with human GPI and antigen-presenting cells were co-cultured with each APL and cytokine production was measured by ELISA to identify antagonistic APLs. Antagonistic APLs were co-immunized with hGPI325-339 to investigate whether arthritis could be antigen-specifically inhibited by APL. After co-immunization, DLN cells were stimulated with hGPI325-339 or APL to investigate Th17 and regulatory T-cell population by flow cytometry, and anti-mouse GPI antibodies were measured by ELISA.
  
  
  RESULTS
  Human GPI325-339-specific Th17 cells showed predominant usage of TCRVbeta8.1 8.2. Among the 20 synthesized APLs, four (APL 6; N329S, APL 7; N329T, APL 12; G332A, APL 13; G332V) significantly reduced IL-17 production by CD4+ T cells in the presence of hGPI325-339. Co-immunization with each antagonistic APL markedly prevented the development of arthritis, especially APL 13 (G332V). Although co-immunization with APL did not affect the population of Th17 and regulatory T cells, the titers of anti-mouse GPI antibodies in mice co-immunized with APL were significantly lower than in those without APL.
  
  
  CONCLUSIONS
  We prepared antagonistic APLs that antigen-specifically inhibited the development of experimental arthritis. Understanding the inhibitory mechanisms of APLs may pave the way for the development of novel therapies for arthritis induced by autoimmune responses to ubiquitous antigens.
authors.affiliation: Department of Clinical Immunology, Doctoral Program in Clinical Science, Graduate School of Comprehensive Human Science, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8575, Japan. namiiwanami@gmail.com
authors.forename: Keiichi
authors.initials: K
authors.lastname: Iwanami
authors.forename: Isao
authors.initials: I
authors.lastname: Matsumoto
authors.forename: Yohei
authors.initials: Y
authors.lastname: Yoshiga
authors.forename: Asuka
authors.initials: A
authors.lastname: Inoue
authors.forename: Yuya
authors.initials: Y
authors.lastname: Kondo
authors.forename: Kayo
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Yoko
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Reiko
authors.initials: R
authors.lastname: Minami
authors.forename: Taichi
authors.initials: T
authors.lastname: Hayashi
authors.forename: Daisuke
authors.initials: D
authors.lastname: Goto
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ito
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Nishimura
authors.forename: Takayuki
authors.initials: T
authors.lastname: Sumida
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000276:immunology*; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D002454:Cell Differentiation / Q000276:immunology; D002469:Cell Separation; D004797:Enzyme-Linked Immunosorbent Assay; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D005434:Flow Cytometry; D005956:Glucose-6-Phosphate Isomerase / Q000276:immunology*; D006801:Humans; D020381:Interleukin-17 / Q000276:immunology; D008024:Ligands; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D008811:Mice, Inbred DBA; D010455:Peptides / Q000276:immunology; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology
chemical_list: D018984:Epitopes, T-Lymphocyte; D020381:Interleukin-17; D008024:Ligands; D010455:Peptides; D016693:Receptors, Antigen, T-Cell, alpha-beta; D005956:Glucose-6-Phosphate Isomerase