IBT/011 Intracellular survival of Staphylococcus aureus and associated immunological dysfunctions in cadmium intoxicated mice

Immune modulation by heavy metals like cadmium may cause serious adverse health effects in humans, although the mechanisms involved are not well understood. Though the actual immunocompetence of animals on toxic metal exposure undergoing a chronic inflammation has been directly studied, no clear information is available regarding the effect of cadmium on the activity of immunocompetent cells. The objective of our study was to demonstrate in an experimental mouse model of bacteremic Staphylococcus aureus infection, clearance of bacteria from blood and spleen in cadmium-treated and control group of mice. Bacterial density was measured in spleen and blood 0, 24, 48 and 72 h post-infection. Our findings have shown a significant load in blood and delayed bacterial clearance from spleen in cadmium-treated group of mice as compared to control. To elucidate the immunomodulatory effects of cadmium, cell-function studies like phagocytosis, intracellular killing and nitric oxide (NO) release were performed on peritoneal macrophages isolated from cadmium-treated and control group of mice. It was found that phagocytic index decreased in Cd treated group from that of control (P<0.05). Percentage of bacterial viability was found higher in case of cadmium treated group as compared to control. Again NO released from the peritoneal macrophages in the treated group with LPS stimulation, showed a lower value when compared to that of control group (P<0.05).