Impact of changes in housing condition on mouse natural killer cell activity

Various psychosocial stressors, such as housing condition and rotation, have been reported to influence tumour growth. This study assessed the influence of housing condition and change in housing condition on natural killer (NK) cell activity, an important component of natural immune defense against cancer. Mice which were individually housed for four weeks did not differ from group-housed mice in NK cell cytolytic activity against tumour targets in vitro or in the frequency of NK cells in the spleen. Switching of housing condition (group to individual, individual to group) for one week did not change the splenic NK cytolytic capacity relative to mice which were not switched. The two groups of mice which experienced a change in housing condition were, however, significantly different from each other. These data suggest that an acute change in housing condition, rather than the housing condition per se, has differential effects on the capacity to kill tumours by NK cells.