title: Anti-CTLA-4 treatment induces IL-10-producing ICOS+ regulatory T cells displaying IDO-dependent anti-inflammatory properties in a mouse model of colitis.
abstract: OBJECTIVE
  Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) has been shown to act as a negative regulator of T cell function and has been implicated in the regulation of T helper 1 (Th1)/Th2 development and the function of regulatory T cells. Tests were carried out to determine whether anti-CTLA-4 treatment would alter the polarisation of naive T cells in vivo.
  
  
  METHODS
  Mice were treated with anti-CTLA-4 monoclonal antibody (mAb) (UC10-4F10) at the time of immunisation or colonic instillation of trinitrobenzene sulfonic acid (TNBS). The cytokines produced by lymph node cells after in vitro antigenic stimulation and the role of indoleamine 2,3 dioxygenase (IDO) and of interleukin-10 (IL-10) were tested, and the survival of mice was monitored.
  
  
  RESULTS
  Injection of anti-CTLA-4 mAb in mice during priming induced the development of adaptive CD4(+) regulatory T cells which expressed high levels of ICOS (inducible co-stimulator), secreted IL-4 and IL-10. This treatment inhibited Th1 memory responses in vivo and repressed experimental intestinal inflammation. The anti-CTLA-4-induced amelioration of disease correlated with IDO expression and infiltration of ICOS(high) Foxp3(+) T cells in the intestine, suggesting that anti-CTLA-4 acted indirectly through the development of regulatory T cells producing IL-10 and inducing IDO.
  
  
  CONCLUSIONS
  These observations emphasise the synergy between IL-10 and IDO as anti-inflammatory agents and highlight anti-CTLA-4 treatment as a potential novel immunotherapeutic approach for inducing adaptive regulatory T cells.
authors.affiliation: Département de Biologie Moléculaire, Laboratoire de Physiologie Animale, Université Libre de Bruxelles, Rue des Pr Jeener et Brachet, 12, 6041 Gosselies, Belgium.
authors.forename: C
authors.initials: C
authors.lastname: Coquerelle
authors.forename: G
authors.initials: G
authors.lastname: Oldenhove
authors.forename: V
authors.initials: V
authors.lastname: Acolty
authors.forename: J
authors.initials: J
authors.lastname: Denoeud
authors.forename: G
authors.initials: G
authors.lastname: Vansanten
authors.forename: J-M
authors.initials: JM
authors.lastname: Verdebout
authors.forename: A
authors.initials: A
authors.lastname: Mellor
authors.forename: J A
authors.initials: JA
authors.lastname: Bluestone
authors.forename: M
authors.initials: M
authors.lastname: Moser
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D015703:Antigens, CD / Q000276:immunology* / Q000378:metabolism; D060908:CTLA-4 Antigen; D003092:Colitis / Q000139:chemically induced / Q000188:drug therapy*; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase / Q000378:metabolism; D016753:Interleukin-10 / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects / Q000378:metabolism*; D014302:Trinitrobenzenesulfonic Acid
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D060908:CTLA-4 Antigen; C556707:Ctla4 protein, mouse; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase; D016753:Interleukin-10; D014302:Trinitrobenzenesulfonic Acid