Abstract

Athletes, in heavy training, can become susceptible to illnesses that suggest that the immune system has become compromised in some way. This study was designed to investigate whether or not the circulating leucocyte numbers and the CD4/CD8 lymphocyte ratios of human subjects varied significantly after 3 exercise protocols specifically designed to stress the aerobic, the glycolytic, or the ADP-ATP: creatinine phosphate metabolic pathways. Circulating lymphocyte numbers were raised immediately after exercise. The CD4/CD8 lymphocyte ratios were significantly lowered following exercise using the glycolytic and phosphate protocols although not after the aerobic protocol. In vitro 3H-DNA synthesis of leucocytes challenged with the polyclonal lymphocyte mitogens PHA, CON A and PWM was also measured, using a standard 3H thymidine incorporation assay. Although these responses were not affected by exercise, the per cent increase in radioactive DNA synthesis in the cultures stimulated by PHA correlated with both pre-exercise CD4/CD8 lymphocyte ratio and with percentage decrease in CD4/CD8 ratio. However, this was not the case with CON A, while the percentage increase in 3H DNA synthesis induced by PWM was significantly related to the reduction in the CD4/CD8 ratio. The results suggest that while leucocyte numbers are raised following exercise, changes in the CD4/CD8 lymphocyte ratios indicate an imbalance of subpopulations of lymphocytes responsible for the modulation of immunity. The T-cell mitogen, PHA, may best define this change. Verf.-Ref.