Abstract
Exercise may attenuate immunosenescence with aging that appears to be accelerated following breast cancer treatment, although limited data on specific cell types exists and acute and chronic exercise have been investigated independently in older adults. PURPOSE: To determine the mucosal associated invariant T (MAIT) cell response to acute exercise before (PRE) and after (POST) 16 weeks of exercise training in breast cancer survivors (BCS) and healthy older women (CON). METHODS: Age-matched BCS and CON performed 45 min of intermittent cycling at 60% peak power output wattage. Blood samples were obtained at rest, immediately (0 h) and 1 h after exercise to determine MAIT cell counts, frequency, and intracellular cytokine expression. RESULTS: At PRE, MAIT cell counts were greater in CON (137%) than BCS at 0 h (46%, p < 0.001), with increased MAIT cell frequency in CON but not BCS. TNFα(+) and IFNγ(+) MAIT cell counts increased at 0 h by ~120% in CON (p < 0.001), while BCS counts and frequencies were unchanged. Similar deficits were observed in CD3(+) and CD3(+) CD8(+) cells. At POST, exercise-induced mobilization and egress of MAIT cell counts and frequency showed trends towards improvement in BCS that approached levels in CON. Independent of group, TNFα frequency trended to improve (p = 0.053). CONCLUSIONS: MAIT mobilization in older BCS following acute exercise was attenuated; however, exercise training may partially rescue these initial deficits, including greater sensitivity to mitogenic stimulation. Using acute exercise before and after interventions provides a unique approach to identify age- and cancer-related immuno-dysfunction that is less apparent at rest.