Acute exercise and T-lymphocyte expression of the early activation marker CD69

This study aimed to determine the effect of acute exercise on the proliferation and expression of activation markers on T-lymphocytes.

Seventeen well-trained male endurance runners completed 60 min of treadmill running at 95% of ventilatory threshold and a resting, no exercise, control session at the same time of day. Five blood samples were collected at each session: before exercise, mid-exercise, immediately after exercise, and 30 min and 60 min after exercise. Isolated peripheral blood mononuclear cells (PBMC) were stimulated with the mitogen PHA. Activation was measured using the expression of CD69 (assessed by three-color flow-cytometry), and cellular proliferation was assessed using 3-(4,5-dimethlthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) dye uptake.

At all sampling points, there was a significant difference (P < 0.05) in the percentage of CD4 and CD8 cells that became activated (CD69+) after mitogen stimulation (68% of CD4 compared with 45% of CD8 cells). Exercise had no effect on the percentage of cells that became activated in response to mitogen. There was a significant exercise-induced decrease in lymphocyte proliferation of PBMC, but when expressed per-T-cell (CD3+), there was no difference between the exercise and control condition.

This study indicated that on an individual cell basis 1 h of exercise at 95% of ventilatory threshold did not alter the ability of T-lymphocytes (CD3+) or T-lymphocyte subsets (CD3+CD4+ and CD3+CD8+) to become activated and did not alter the ability of T-lymphocytes to proliferate.