title: Higher sensitivity of male CD4+ T cells to suppressive effects of CD8+ T cells on IL-5 production compared to female CD4+ T cells.
abstract: BACKGROUND
  Asthma prevalence and severity are higher in females than in males after puberty. The underlying mechanisms of this gender difference are not fully understood. More severe airway inflammation in female mice has been reported to be associated with higher levels of T helper type 2 (Th2) cytokines in asthma models. The aim of this study was to investigate sex differences in CD4+ and CD8+ T cell functions in Th2 cytokine production.
  
  
  METHODS
  Splenocytes from naive mice were stimulated with anti-CD3/CD28 antibodies and the proportions of CD4+ and CD8+ T cells were analyzed. CD4+ T cells were stimulated in the presence of CD8+ T cells. The concentrations of interleukin (IL)-5, IL-10 and interferon (IFN)-γ in the cultures were measured.
  
  
  RESULTS
  The concentration of IL-5, but not IFN-γ, was significantly higher in female splenocytes than in male splenocytes. There were no sex differences in the proportions of CD4+ and CD8+ T cells in the splenocytes. Although the IL-5 production levels in male and female CD4+ T cells were similar, IL-5 production in male CD4+ T cells, but not female CD4+ T cells, was suppressed by both male and female CD8+ T cells. While IL-5 and IL-10 were not detected in the cultures from both male and female CD8+ T cells, IFN-γ concentration in female CD8+ T cells was significantly higher than in male CD8+ T cells.
  
  
  CONCLUSIONS
  The sex difference in the sensitivity of CD4+ T cells to CD8+ T cell suppression might contribute to the sex difference in IL-5 production by splenocytes.
authors.affiliation: Department of Pathophysiology, Tohoku Pharmaceutical University, Sendai, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Okuyama
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Kashimura
authors.forename: Tasuku
authors.initials: T
authors.lastname: Kawano
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ohkawara
authors.forename: Motoaki
authors.initials: M
authors.lastname: Takayanagi
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Kikuchi
authors.forename: Isao
authors.initials: I
authors.lastname: Ohno
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D005260:Female; D015848:Interleukin-5 / Q000276:immunology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D012737:Sex Factors; D013154:Spleen / Q000166:cytology
chemical_list: D015848:Interleukin-5; D011948:Receptors, Antigen, T-Cell