Stress-induced impairment of macrophage tumoricidal function.

Several studies have shown the effect of stress on immune cells and their functions. The purpose of the present work was to investigate the influence of acute immobilization stress on macrophage nonspecific tumoricidal activity. Peritoneal macrophages were activated by nonspecific immunopotentiators such as interferon or bacterial lipopolysaccharide (LPS) and the killing of MBL-2 leukemic target cells was measured. Macrophages from mice submitted to stress showed decreased responsiveness to interferon or LPS. In addition, the role of corticosteroids as mediators in the phenomenon was also studied. Indeed, we observed that corticosteroids were able to inhibit macrophage cytotoxicity and could at least play some role. This data could contribute to a better understanding of the effect of stress on the host immunosurveillance against tumor development.