title: Modulation of NK cell cytolytic activity by macrophages in chronically exercise-stressed mice.
abstract: This study was designed to investigate the effects of moderate-intensity endurance training on basal natural killer (NK) cell cytolytic activity in murine splenocytes that were enriched for 1) NK1.1+ cells or 2) macrophages and NK1.1+ cells. Mice were assigned to sedentary (Sed), treadmill control (TM), or treadmill-trained (Trn) groups. Splenocyte number, the percentages of NK1.1+, large granular lymphocytes (NK1.1+, LGL-1+), and other subpopulations did not change in Trn mice. Approximately 70% of cells enriched for NK1.1+ expressed this surface antigen. Lytic units (LU) expressed per LGL-1+ cell were significantly lower in Trn [83.9 +/- 3.2 (SE)] compared with Sed (109.5 +/- 7.5) and TM (101.3 +/- 6.4) groups. When macrophages remained in the in vitro assay, LU per LGL-1(+) cell did not differ across groups. The results indicate that highly enriched NK1.1+ cells from Trn mice had lower NK cell activity compared with Sed mice. No differences in NK cell activity were observed when cells were enriched for NK1.1+ cells and macrophages. These findings support the hypothesis that macrophage modulation of NK cells may be one mechanism contributing to augmented basal NK cell activity in endurance-trained individuals.
authors.affiliation: Department of Kinesiology, Washington State University, Pullman, Washington 99164-1410, USA. Blank@mail.wsu.edu
authors.forename: S E
authors.initials: SE
authors.lastname: Blank
authors.forename: T B
authors.initials: TB
authors.lastname: Jones
authors.forename: E G
authors.initials: EG
authors.lastname: Lee
authors.forename: C J
authors.initials: CJ
authors.lastname: Brahler
authors.forename: R M
authors.initials: RM
authors.lastname: Gallucci
authors.forename: M L
authors.initials: ML
authors.lastname: Fox
authors.forename: G G
authors.initials: GG
authors.lastname: Meadows
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002908:Chronic Disease; D005260:Female; D007694:Killer Cells, Natural / Q000502:physiology*; D008214:Lymphocytes / Q000502:physiology; D008264:Macrophages / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D010805:Physical Conditioning, Animal; D010807:Physical Endurance / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology*; D013154:Spleen / Q000166:cytology; D013312:Stress, Physiological / Q000503:physiopathology*