The Effects of Age and Latent Cytomegalovirus Infection on NK-Cell Phenotype and Exercise Responsiveness in Man

Abstract

The redeployment of NK-cells in response to an acute bout of exercise is thought to be an integral component of the “fight-or-flight” response, preparing the body for potential injury or infection. We showed previously that CMV seropositivity impairs the redeployment of NK-cells with exercise in the young. In the current study, we examined the effect of aging on the redeployment of NK-cells with exercise in the context of CMV. We show here that CMV blunts the exercise-induced redeployment of NK-cells in both younger (23–39 yrs) and older (50–64 yrs) subjects with older CMVneg subjects showing the largest postexercise mobilization and 1 h postexercise egress of NK-cells. The blunted exercise response in CMVpos individuals was associated with a decreased relative redeployment of the CD158a+ and CD57+ NK-cell subsets in younger and older individuals. In addition, we show that aging is associated with a CMV-independent increase in the proportion of NK-cells expressing the terminal differentiation marker CD57, while CMV is associated with an age-dependent decrease in the proportion of NK-cells expressing the inhibitory receptors KLRG1 (in the younger group) and CD158a (in the older group). Collectively, these data suggest that CMV may decrease NK-cell mediated immunosurveillance after exercise in both younger and older individuals.

Effects of Acute and Chronic Exercise on Immunological Parameters in the Elderly Aged: Can Physical Activity Counteract the Effects of Aging?

“…This redeployment is stepwise and preferential in the sense that it involves NK-subsets exhibiting a high differentiation phenotype (KIR+/NKG2A– vs. medium-differentiated KIR+/NKG2A+ and low-differentiated KIR–/NKG2A+). Bigley and co-authors ( 72 ) were able to replicate this finding in a sample of 40 subjects (50–64 vs. 23–39 years) undergoing 30 min of cycling exercise at 80% of maximum power. Interestingly, the post-exercise response to CMV was similar between young and old individuals ( 72 ).…”

“…Bigley and co-authors ( 72 ) were able to replicate this finding in a sample of 40 subjects (50–64 vs. 23–39 years) undergoing 30 min of cycling exercise at 80% of maximum power. Interestingly, the post-exercise response to CMV was similar between young and old individuals ( 72 ).…”

“…Generally, most types of exercise can increase NK cell function and number ( 57 , 72 , 117 , 118 ). Brahmi and colleagues ( 117 ) recruited both trained and sedentary individuals, who underwent a progressive cycle ergometer test using an incremental work load of 15 W (90 kpm), increasing every minute.…”

Effect of CMV and Aging on the Differential Expression of CD300a, CD161, T-bet, and Eomes on NK Cell Subsets

“…Thus, whereas different studies have shown an age-associated increased expression of KIR (20, 62) and a decreased expression of NKG2A (20), others have not found significant differences in the expression of KIR or NKG2A in the elderly (14, 17, 18, 30) or even a decreased expression of KIR (CD158a) in middle age donors if they are CMV-seropositive (63). The expression of another inhibitory receptor KLRG-1 is significantly reduced with aging (21) and with CMV seropositivity in the young individuals (63). …”

Older men display elevated levels of senescence-associated exercise-responsive CD28nullangiogenic T cells compared with younger men

“…D -**significant difference ingress and egress between CD28 null and CD28 + CD8 + T ANG cells in older individuals (P < 0.05). (Simpson et al 2007;Turner et al 2010;Witard et al 2012), with age differences apparent for various subpopulations of T cells (Spielmann et al 2014;Bigley et al 2015;Ross et al 2018). In this study, we show that older adults mobilize T ANG cells to a lesser extent than younger adults, albeit not statistically significant, with younger individuals mobilizing over 29 more T ANG cells in response to the exercise stressor.…”