title: Aerobic fitness is associated with lower proportions of senescent blood T-cells in man.
abstract: Senescent T-cells accumulate with age, lowering the naïve T-cell repertoire and increasing host infection risk. As this response is likely to be influenced by certain lifestyle factors, we examined the association between aerobic fitness (VO(2max)) and the age-related accumulation of senescent T-cells. Blood lymphocytes from 102 healthy males (18-61 yr) were analyzed for KLRG1, CD57, CD28, CD45RA, CD45RO surface expression on CD4+ and CD8+ T-cells by 4-color flow cytometry. Advancing age (yr) was positively associated with the proportion (%) of senescent (KLRG1+/CD57+; KLRG1+/CD28-) CD4+ (B=1.00; 1.02) and CD8+ (B=0.429; 1.02) T-cells and inversely associated with naïve (KLRG1-/CD28+) CD4+ (B=-1.000) and CD8+ (B=-0.993) T-cells. VO(2max) was inversely associated with senescent CD4+ (B=-0.97) and CD8+ (B=-0.240). Strikingly, age was no longer associated with the proportions of senescent or naïve T-cells after adjusting for VO(2max), while the association between VO(2max) and these T-cell subsets withstood adjustment for age, BMI and percentage body fat. Ranking participants by age-adjusted VO(2max) revealed that the highest tertile had 17% more naïve CD8+ T-cells and 57% and 37% less senescent CD4+ and CD8+ T-cells, respectively, compared to the lowest tertile. VO(2max) was not associated with latent cytomegalovirus (CMV), Epstein-Barr virus (EBV) or herpes simplex virus-1 (HSV-1) infection, indicating that the moderating associations of VO(2max) were not confounded by persistent viral infections. This is the first study to show that aerobic fitness is associated with a lower age-related accumulation of senescent T-cells, highlighting the beneficial effects of maintaining a physically active lifestyle on the aging immune system.
authors.affiliation: Laboratory of Integrated Physiology, Department of Health and Human Performance, University of Houston, 3855 Holman Street, Houston, TX 77204, USA.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Spielmann
authors.forename: Brian K
authors.initials: BK
authors.lastname: McFarlin
authors.forename: Daniel P
authors.initials: DP
authors.lastname: O'Connor
authors.forename: Paula J W
authors.initials: PJ
authors.lastname: Smith
authors.forename: Hanspeter
authors.initials: H
authors.lastname: Pircher
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Simpson
mesh_terms: D000293:Adolescent; D000328:Adult; D015308:Anaerobic Threshold / Q000502:physiology; D000954:Antigens, Surface / Q000032:analysis; D001823:Body Composition / Q000502:physiology; D015992:Body Mass Index; D016922:Cellular Senescence / Q000502:physiology*; D003586:Cytomegalovirus Infections / Q000097:blood; D020031:Epstein-Barr Virus Infections / Q000097:blood; D015444:Exercise / Q000502:physiology*; D005434:Flow Cytometry; D006561:Herpes Simplex / Q000097:blood; D006801:Humans; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000502:physiology; D009043:Motor Activity / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology*; D012044:Regression Analysis; D013601:T-Lymphocytes / Q000502:physiology*; D055815:Young Adult
chemical_list: D000954:Antigens, Surface