Respiratory burst and candidacidal activity of peritoneal macrophages are impaired in copper-deficient rats

To investigate the effect of dietary copper deficiency on the function of peritoneal macrophages, weaned male Lewis rats were pair-fed diets containing either adequate (7 mg/kg diet; +Cu) or deficient (0.7 mg/kg diet; -Cu) levels of copper for 5 wk. Cellular copper content and the activity of Cu, Zn superoxide dismutase were significantly lower in both resident and thioglycollate-elicited macrophages from -Cu rats than in cells from +Cu controls. Reduced cellular Cu status was associated with impaired respiratory burst as assessed by zymosan-induced chemiluminescent activity and superoxide anion (O2-) generation. Candidacidal activity of macrophages from -Cu rats was also reduced and was highly correlated with chemiluminescent activity and O2- generation. In contrast, phagocytosis of opsonized erythrocytes by peritoneal macrophages from -Cu rats was normal. Elicited peritoneal macrophages from marginally Cu-deficient rats also killed significantly fewer yeast cells than macrophages from +Cu rats. These results demonstrate that macrophage function is impaired by dietary Cu deficiency and that the candidacidal activity of these cells may provide a sensitive indicator of Cu status.