Exercise Increases Mucosal-associated Invariant T Cell Cytokine Expression but Not Activation or Homing Markers

Abstract

Mucosal associated invariant T (MAIT) have properties of both the innate and adaptive immune systems but are an understudied population within exercise immunology. These lymphocytes aggregate at the mucous membranes, but it is unknown if submaximal exercise alters their circulating numbers or function. PURPOSE:To determine the MAIT cell response to submaximal exercise on activation and homing marker expression and stimulated cytokine production. METHODS:Twenty healthy, young, recreationally active males cycled for 40 min at 86% of V T following an overnight fast. Peripheral blood mononuclear cells were isolated and labelled to identify specific MAIT cell populations using flow cytometry. Cytokine production following stimulation was also determined. RESULTS:MAIT cells were 2.9% of T-cells and increased to 3.9% after exercise and with recovery whereas cell numbers significantly increased by 91.5% following exercise before returning to resting levels. Chemokine and activation marker absolute cell number significantly increased while expression levels remained constant but the high levels of CCR5 may help direct MAIT cells to sites of inflammation. Following stimulation, TNFα expression significantly increased after exercise before returning to baseline with a similar trend for IFNγ. CONCLUSIONS:MAIT cell numbers undergo a partial biphasic response following submaximal exercise and appear to be preferentially mobilized within T-cells; however, the magnitude of the submaximal response was attenuated relative to maximal exercise. Stimulated MAIT cells increase TNFα expression, indicating greater responsiveness to pathogens following acute exercise.

Natural killer cell mobilization and egress following acute exercise in men with prostate cancer

“…Freshly isolated peripheral blood mononuclear cells (PBMCs) were labelled as previously (Hanson et al., 2017; 2019,). Briefly, whole blood was diluted in phosphate‐buffered saline (PBS) and isolated using SepMate‐50 (Stemcell, Vancouver, BC, Canada) following the manufacturer's instructions.…”

“…Fluorescence minus one and single colour compensation tubes were used with every experiment. NK cell counts (cells µl −1 ) were determined by multiplying the percentage of each population with the haematology lymphocyte count (Hanson et al., 2017; 2019). NK cell subpopulation counts were determined using the NK cell count and the percentage of the respective daughter populations for each specific cell type.…”

Mucosal-associated invariant T cells and disease

“…The marked heterogeneity among patients with regard to factors -such as age 107,108 , body mass index 16,73 , physical activity 109 and ongoing treatment 69,90,110 -that could impact MAIT cell frequency and function might explain the conflicting results in human studies 71,111 . For example, decreased blood MAIT cell frequency is observed in adults but not in children with coeliac disease 74 , and in obesity MAIT cell frequency is increased in children but decreased in adults 16,73 .…”

Mucosal-Associated Invariant T Cell Response to Acute Exercise and Exercise Training in Older Obese Women

“…In healthy young men, maximal acute exercise increased MAIT-cell counts by 2.2-fold and cell frequencies by 0.8%, suggesting a preferential mobilization among T-cell populations [16]. In response to submaximal acute aerobic exercise, MAIT-cell counts increased by 92% and cell frequency by 1.0% along with an increased proportion of mitogen stimulated MAIT-cells expressing TNF-α was reported, indicating increased sensitivity to MAIT-cell stimulation [17]. MAIT-cells have displayed an intensity dependent numerical mobilization similar to conventional CD8+ T-cells [18].…”