Modulation of Natural Killer Cell Activity in Peripheral Blood by Physical Exercise

Abstract

The present study was designed to examine the effect of physical exercise on human natural killer (NK) cells. Six healthy volunteers underwent two different acute physical exercise tests with an interval of at least 1 week: (1) 60 min bicycle exercise at 80% of maximal oxygen uptake (VO2max) and (2) 60 min back-muscle training at up to 29% of VO2max; blood samples were collected before and during the last few minutes of exercise, as well as 2 h and 24 h afterwards. The NK cell activity (lysis/fixed number of mononuclear cells) increased during bicycle exercise, dropped to a minimum 2 h later and returned to pre-exercise levels within 24 h. Back-muscle exercise did not significantly influence NK cell activity. Plasma levels of adrenaline, noradrenaline, and cortisol were elevated during bicycling, but not during back-muscle exercise, indicating that exercise intensity is a determinant of NK cell activity. During bicycle exercise the NK cell subset (CD16- cells) of mononuclear cells increased significantly. Furthermore an improved interleukin 2 (IL-2) boosting of the NK cell activity was found during work as compared to IFN-alpha and indomethacin-enhanced NK cell activity. These results indicate that NK cells with a high IL-2 response capacity are recruited to the peripheral blood during exercise. The decreased NK cell activity demonstrated 2 h after work was probably not due to fluctuations in size of the NK cell pool, since the proportion of CD16+ cells was normal. The finding that indomethacin fully restored the suppressed NK cell activity in vitro and the demonstration of a twofold increase in monocyte (CD20+ cells) proportions 2 h after work, strongly indicate that prostaglandins released by monocytes during the heavy physical exercise are responsible for the down-regulation of the NK cells.

The effect on immunity of long-term intensive training in elite swimmers

“…A fall in NK cell numbers after exercise has been reported by other investigators studying the acute effects of exercise on immunity [12,14,19,21] and may reflect a physiological redistribution of NK cells out of peripheral blood during intensive physical training [17]. However, it has also been shown that levels of NK cell numbers return to normal within 24 h [12-17,19].…”

“…In contrast, highly trained athletes and sedentary individuals subjected to training sessions [3,[10][11][12][13][14][15][16][17][18][19]. While some changes are transitory and related to the acute effect of intense exercise, the changes in leucocyte numbers [14] and cytokine levels [18] in peripheral blood have been shown to persist for several days.…”

Regulation of inflammation in the adipose tissue in cancer cachexia: effect of exercise

“…TNF-a, IL-1b and IL-6, in laboratory animals or in humans. 25 TNF-a is markedly related to the worsening of cachexia, and several therapies have been adopted in attempt to block its action. However, so far, most of the studies have failed in restoring the damage caused by this cytokine.…”

“…21 Cytokines facilitate the inflow of lymphocytes, neutrophiles, monocytes and other cells to focci of tissue and/or systemic inflammation. 25 Local inflammation is followed by a systemic response, known as acute phase response. 21 This response includes the production of countless acute phase proteins by the liver, such as C-reactive protein (CRP), which can be diminished by local injection of cytokines, e.g.…”

The Effects of Aqueous Extracts of <i>Acalypha wilkesiana</i> Supplementation and Exercise Training on Hematopoietic System in Rats

“…This is in accordance with these findings. The fall in CD4/ CD8 ratio is mainly due to an increase in the number of CD8 T cells, the change in the lymphocyte subsets is transient, basal level usually being reached within one and half hour after exercise [25]. Table 2 shows a decrease in the level of immunoglobulin G (IgG) after the exercise with or without the aqueous extract of A. wilkesiana may be due to the immuno suppressive effects of the increase production of cortisol occasioned by the stress response during exercising to exhaustion.…”