title: Antigen-primed splenic CD8+ T cells impede the development of oral antigen-induced allergic diarrhea.
abstract: BACKGROUND
  Although CD4+ T-cell populations are thought to be involved in the pathophysiology of food allergy and oral tolerance, the role of CD8+ T cells remains uncertain.
  
  
  OBJECTIVE
  We analyzed regulatory effects of adoptively transferred CD8+ T cells on the development of allergic diarrhea in antigen-sensitized mice that had a significantly reduced number of conventional TCRalphabeta+ CD8+ T cells.
  
  
  METHODS
  Ovalbumin-specific T-cell receptor transgenic mice were systemically sensitized to ovalbumin. Splenic CD8+ T cells purified from ovalbumin-sensitized or nonsensitized wild-type mice or IL-10 knockout mice were adoptively transferred to ovalbumin-sensitized ovalbumin-specific T-cell receptor transgenic mice. Allergic diarrhea induced by oral administration of ovalbumin, ovalbumin-specific immunoglobulin production, and cytokine production in intestines and mesenteric lymph nodes were assessed.
  
  
  RESULTS
  Adoptive transfer of splenic CD8+ T cells from ovalbumin-primed mice, but not from nonprimed mice, suppressed the development of allergic diarrhea, which was associated with in vivo increased IL-10 mRNA expression and in vitro antigen-specific IL-10 production by mesenteric lymph node cells. Upregulation of serum ovalbumin-specific IgE was not suppressed by ovalbumin-primed CD8+ T-cell transfer. Although administration of IL-10 before ovalbumin challenge failed to alleviate allergic diarrhea, transfer of splenic CD8+ T cells from IL-10 knockout mice showed diminished preventive effects.
  
  
  CONCLUSIONS
  Systemic immunization with allergen simultaneously induces regulatory CD8+ T cells that can inhibit the development of allergic diarrhea. IL-10 production by regulatory CD8+ T cells appears to be partially involved in these inhibitory mechanisms.
authors.affiliation: Department of Pediatrics, Faculty of Medical Sciences, University of Fukui, Fukui, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Yamada
authors.forename: Yusei
authors.initials: Y
authors.lastname: Ohshima
authors.forename: Motoko
authors.initials: M
authors.lastname: Yasutomi
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Ogura
authors.forename: Shuko
authors.initials: S
authors.lastname: Tokuriki
authors.forename: Hironobu
authors.initials: H
authors.lastname: Naiki
authors.forename: Mitsufumi
authors.initials: M
authors.lastname: Mayumi
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis; D003967:Diarrhea / Q000517:prevention & control*; D005512:Food Hypersensitivity / Q000517:prevention & control*; D007073:Immunoglobulin E / Q000097:blood; D016753:Interleukin-10 / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D010047:Ovalbumin / Q000276:immunology*; D011948:Receptors, Antigen, T-Cell / Q000502:physiology; D013154:Spleen / Q000276:immunology*
chemical_list: D016207:Cytokines; D011948:Receptors, Antigen, T-Cell; D016753:Interleukin-10; D007073:Immunoglobulin E; D010047:Ovalbumin