Energy restriction and exercise differentially enhance components of systemic and mucosal immunity in mice

The prevalence of obesity, an established risk factor for several chronic diseases, including cancer, has risen dramatically over the past 4 decades. Dietary change and/or increased physical activity are the most commonly recommended lifestyle-based strategies for preventing or reversing obesity. One of several physiological systems that may be enhanced by dietary change and exercise is the immune system. In this study, we examined the effects of energy restriction (ER; 30% reduction relative to control energy intake) and/or exercise (EX; voluntary wheel running) on systemic and mucosal immune function. Female C57BL/6 mice were randomized into 4 treatment conditions: 1) controls consumed ad libitum (AL); 2) AL with access to running wheels (AL + EX); 3) 30% ER; and 4) 30% ER with access to running wheels (ER + EX). Both ER and EX reduced spleen weight and the number of splenic T and B lymphocytes (P < 0.05). ER enhanced natural killer (NK) cell function, but reduced concanavalin A (Con A)-induced T-cell proliferation (P < 0.05). In contrast, EX enhanced Con A-induced proliferation and cytokine production from Peyer's patch cells (P < 0.05). These data suggest that ER and EX enhance some, but not all, components of the immune system and are likely working via different biological mechanisms to regulate NK and T-cell function.