Abstract
The effect of a treadmill exercise bout (30 m/ min, 4° slope, 30 min) or 9 weeks of training (18m/min, 0° slope, 45 min/day, 5 x/week) on splenic natural killer cell activity (NKCA) and BLT-esterase activity was studied in adult C3/Hc male mice. These immune parameters were assessed in mice who had been injected i.p. 24 h before sacrifice with saline or poly I:C, an interferon inducer and activator of killer cells in vivo. Acutely exercised mice pre-rcated with saline had an increase in NKCA and BLT-esterase activity 5 minutes after cessation of exercise relative to values at rest. The frequency of asialo GM1 positive splenocytes did not differ in the saline injected, acutely exercised mice compared to values obtained before exercise. Animals pretreated with poly I:C did not differ in their NKCA or BLT-esterase activity as a function of time. Trained mice injected with saline had a significant increase in the in vitro splenic NKCA and in the frequency of splenocytes positive for asialo GM1 compared with sedentary controls. However, BLT-esterase activities did not differ by training status. Pretreatment with poly I:C augmented NKCA in all groups of mice and abolished the significant effects observed with acute exercise or training on fresh natural killer cells. These results indicate that the increase in splenic natural killer cell activity immediately after acute exercise is accompanied by an increase in the activity of the granule lytic enzyme, BLT-esterase, presumably involved in delivery of the 'lethal hit'. These results also suggest different mechanisms for the increase in natural killer cell cytolytic activity with acute exercise and with training.
Key words
Natural killer cells - granule exocytosis - granzymes - treadmill running
