Changes In The Proportions Of CD56 dim And CD56bright Natural Killer Cells During And After Acute Exercise

Abstract

Our previous research has shown changes in the relative proportions of natural killer (NK) cell subsets with high and low cytotoxic activities during incremental exercise. Such changes suggest a potential differential mobilization of NK cell subsets during and after acute exercise. PURPOSE: To determine the relative proportions of CD3-CD16brigthCD56dim (CD56dim) and CD3−CD16dim/−CD56bright(CD56bright) NK cells, as a percentage of total lymphocyte counts, during and after moderate exercise (intensities between AT and OBLA). METHODS: Six male students (age: 20.2±0.7 yrs, VO2max: 59.1±2.6 ml•kg-1•min−1) exercised on a cycle ergometer for 30 min at 120% of their individual ventilatory thresholds (69.7±0.1 %VO2max). Blood samples were taken at rest, at the end of exercise, and 5, 30, 60, 90, and 120 min post-exercise. The phenotypes of circulating NK cells were determined by flow cytometry. Possible effects were analyzed using a one-factor ANOVA, and applying Bonferroni's post hoc test for multiple comparisons. RESULTS: The proportion of CD56dim NK cells, expressed as a percentage of total lymphocyte counts, increased significantly (p < 0.001) during exercise, but dropped below the resting level at 60 min post-exercise (p < 0.001). In contrast, the percentage of CD56bright NK cells tended to increase at 30 min post-exercise, but remained statistically unchanged throughout the experiments. CONCLUSIONS: These results suggest that an acute bout of exercise induces a differential the mobilization of CD56dim and CD56bright NK cell subsets.