title: Aerobic training increases the stimulated percentage of CD4+CD25+ in older men but not older women.
abstract: The purpose of the present study was to determine whether 12 months of moderate intensity cycling would increase the expression of IL-2 (CD25+) receptors in T helper (CD4+) lymphocytes in men and women aged 65-75 years. Fourteen men and 10 women completed 52 weeks of moderate intensity cycling (60% VO2peak). Subjects trained (TR) three times per week for 45 min per session. Eight age-matched untrained (UT) male and eight UT female subjects acted as controls. Resting blood samples were taken from TR and UT subjects every 4 weeks. Leukocyte concentration was measured using a full blood count. PHA-stimulated CD4+ lymphocytes were analysed for changes in the expression of CD25+, by flow cytometry. Training significantly increased VO2peak (l min(-1), ml kg(-1) min(-1)) in male (+14.3, +16%) and female (+16.7, +27.8%) groups. The TR male group showed a significantly lower percentage of CD4+CD25+ than the male UT in January but the TR male percentage was significantly higher than the UT male group during February, March, April, May, June, September B and December. The female TR group showed a significantly higher percentage CD4+CD25+ than the female UT only during July. There were also significant sequential monthly changes in the percentage of CD4+CD25+ for male and female UT and TR groups. Significant increases in the percentage of CD4+CD25+ in the male TR group suggest training-enhanced lymphocyte mitogenic responsiveness. Moderate intensity long-term training may increase the recruitment of active memory CD4+CD25+ in men rather than women.
authors.affiliation: Institute of Food, Nutrition and Human Health, Massey University, Private Bag 756, Wellington, New Zealand. S.Broadbent@massey.ac.nz
authors.forename: Suzanne
authors.initials: S
authors.lastname: Broadbent
authors.forename: Gregory
authors.initials: G
authors.lastname: Gass
mesh_terms: D000368:Aged; D000375:Aging / Q000276:immunology; D015704:CD4 Antigens / Q000097:blood*; D004562:Electrocardiography; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006801:Humans; D053645:Interleukin-2 Receptor alpha Subunit / Q000097:blood*; D007958:Leukocyte Count; D008214:Lymphocytes / Q000166:cytology / Q000276:immunology*; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D012621:Seasons; D012727:Sex Characteristics
chemical_list: D015704:CD4 Antigens; D053645:Interleukin-2 Receptor alpha Subunit