title: Aging exacerbates restraint stress-induced inhibition of antigen-specific antibody production in mice.
abstract: BACKGROUND
  We have recently found that exposure to acute restraint stress suppresses antigen-specific antibody production, including IgE, in a murine model of allergic rhinitis. Although age-related alterations in immune responses are known, it remains unclear whether aging modulates the antibody production under stressful conditions. In this study, we set out to determine the effects of aging on antibody production under acute restraint stress in mice.
  
  
  METHODS
  Both young and aged CBA/J mice were repeatedly sensitized intranasally with phospholipase A2 (PLA2) without adjuvants. Restraint stress was applied using uniform cylinders once a week for a continuous 8h period, on 5 occasions in total. Blood samples were taken at 0, 20 and 30 days after primary sensitization, and production of PLA2-specific antibodies and levels of IL-4, IFN-gamma, IL-10 and IL-1 beta in sera were determined by ELISA.
  
  
  RESULTS
  Repeated intranasal sensitization with PLA2 induced PLA2-specific IgE, IgG1 and IgG2a production in aged mice. We found that exposure to restraint stress significantly inhibited production of PLA2-specific IgE, IgG1 and IgG2a in aged mice. In addition, antibody production under restraint stress decreased significantly in aged mice when compared with young mice. No IL-4, IFN-gamma, IL-10 or IL-1 beta were detected in sera from non-stressed or stressed aged mice.
  
  
  CONCLUSIONS
  Aging exacerbates the immunosuppressive role of acute restraint stress in antigen-specific antibody production in mice.
authors.affiliation: Hygiene and Public Health, Social Medicine, Faculty of Medicine, Kagawa University, Kagawa, Japan.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Ichihara
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Okano
authors.forename: Keiko
authors.initials: K
authors.lastname: Nishioka
authors.forename: Noriko
authors.initials: N
authors.lastname: Manabe
authors.forename: Naoto
authors.initials: N
authors.lastname: Ichihara
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Jitsunari
authors.forename: Tazuko
authors.initials: T
authors.lastname: Fujiwara
authors.forename: Kazunori
authors.initials: K
authors.lastname: Nishizaki
mesh_terms: D000375:Aging / Q000276:immunology*; D000818:Animals; D000917:Antibody Formation; D016207:Cytokines / Q000097:blood; D005260:Female; D007073:Immunoglobulin E / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D051379:Mice; D008808:Mice, Inbred CBA; D054467:Phospholipases A2 / Q000276:immunology*; D012149:Restraint, Physical; D013315:Stress, Psychological / Q000276:immunology*
chemical_list: D016207:Cytokines; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007073:Immunoglobulin E; D054467:Phospholipases A2