LYMPHOKINE-ACTIVATED KILLER-CELL ACTIVITY FOLLOWING VOLUNTARY PHYSICAL-ACTIVITY IN MICE

The effect of eight weeks of voluntary wheel running exercise in femal e, outbred Swiss Webster mice on baseline splenic natural killer (NK) cell and interleukin-2 stimulated lymphokine activated killer (LAK) ce ll activity was studied. NK cell cytolytic activity against YAC-1 tumo ur targets was measured using a Cr-51 release assay at the completion of a wheel running episode (end of dark cycle) or at 96 h after cessat ion of wheel running. LAK cell activity against tumour targets was gen erated from splenic NK cells by in vitro stimulation for 3 days with r ecombinant interleukin-2 (rIL-2). Wheel running was not associated wit h increases in baseline NK cytolytic activity either when sampled as a training effect (96 b after exercise) or immediately after exercise. Following an episode of wheel running exercise, LAK activity was signi ficantly higher in the physically active compared to sedentary animals . These results support the concept that spontaneous wheel running act ivity enhances lymphokine activated killer cell activity following a c ycle of active running; whether this greater LAK activity involves cha nges in IL-1, IL-2, or other cytokine concentrations or in the express ion of IL-2 receptors on NK/LAK cells after exercise warrants further investigation. Given the clinical use of IL-2 to stimulate LAK cells i n adoptive immunotherapy, it is possible (although untested) that exer cise may have a potentially beneficial role as a treatment modality fo r some human cancers.