Hanson ED, Bates LC, Harrell EP, et al. - The present study was performed to ascertain the mucosal associated invariant T (MAIT) cell response to acute exercise before and after 16 weeks of exercise training in breast cancer survivors (BCS) and healthy older women. Researchers collected blood samples at rest, immediately (0 h) and 1 h after exercise to determine MAIT cell counts, frequency, and intracellular cytokine expression. The findings revealed that MAIT mobilization in older BCS following acute exercise was attenuated; nevertheless, exercise training may partially rescue these initial deficits, including greater sensitivity to mitogenic stimulation. Before and after interventions, using acute exercise provides a unique approach to distinguish age- and cancer-related immune-dysfunction that is less apparent at rest.