Coping in an intermittent swim stress paradigm compromises natural killer cell activity in rats

► We evaluate the impact of intermittent swim stress on NK cell cytotoxicity. ► We also examine the effects of stressor controllability on this immune endpoint. ► Controllable swim stress results in the greatest suppression of NK cell function. ► Effect occurs immediately post-stress when circulating levels of CORT are highest. ► These results demonstrate an immunological cost of coping in this paradigm.