title: Inhibition of decrease in natural killer cell activity in repeatedly restraint-stressed mice by a biological response modifier derived from cultured mycelia of the basidiomycete Tricholoma matsutake.
abstract: OBJECTIVE
  To develop a method to cope with stress-induced reduction in immunocompetence, we evaluated the immunomodulatory activities of a biological response modifier derived from the mycelia of the basidiomycete Tricholoma matsutake (CM6271) in mice under repeated restraint stress.
  
  
  METHODS
  C57BL/6 mice were inserted, one per tube, into 50-ml polypropylene tubes into which more than 30 ventilation holes had been drilled, and were restrained everyday for 20 days in this fashion for set periods of time. Natural killer (NK) cell activity and NK1.1-positive cell counts in the spleen, ACTH and corticosterone levels in the blood were determined. CM6271 was orally administered daily during the restraint stress period.
  
  
  RESULTS
  (1) When the mice were restrained in a confined space for 6 h per day for 20 days, the NK cell activity and the NK1.1-positive cell counts in the spleen significantly decreased after day 5 with an increase in the blood ACTH and corticosterone levels. (2) Oral administration of CM6271 during the restraint stress period significantly prevented the stress-induced decrease in NK cell activity. The effect was dependent on the timing, duration, and doses administered. (3) CM6271 did not significantly affect the splenic NK1.1-positive cell counts or the levels of blood ACTH and corticosterone in restraint-stressed mice.
  
  
  CONCLUSIONS
  The above findings suggest that CM6271 inhibits the restraint stress-induced decrease of NK cell activity in a timing of administration and dose-dependent manner.
authors.affiliation: Department of Hygiene and Public Health (I), School of Medicine, Tokyo Woman's Medical University, Tokyo, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Ishihara
authors.forename: Hiroko
authors.initials: H
authors.lastname: Iijima
authors.forename: Yoko
authors.initials: Y
authors.lastname: Yagi
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Hoshi
authors.forename: Kenichi
authors.initials: K
authors.lastname: Matsunaga
mesh_terms: D000818:Animals; D001487:Basidiomycota / Q000737:chemistry*; D007155:Immunologic Factors / Q000276:immunology / Q000494:pharmacology*; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology*; D008213:Lymphocyte Activation / Q000187:drug effects; D018655:Lymphocyte Count; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D025282:Mycelium / Q000737:chemistry; D015213:Neuroimmunomodulation / Q000187:drug effects*; D012149:Restraint, Physical; D013047:Specific Pathogen-Free Organisms; D013312:Stress, Physiological / Q000276:immunology*
chemical_list: D007155:Immunologic Factors