INTERLEUKIN-8 ENHANCES NONOXIDATIVE INTRACELLULAR KILLING OF MYCOBACTERIUM-FORTUITUM BY HUMAN GRANULOCYTES

The results of this study show that recombinant interleukin-8 (IL-8) e nhances the intracellular killing of Mycobacterium fortuitum by human granulocytes. This chemokine did not stimulate the phagocytosis of M. fortuitum by granulocytes at various bacterium-to-cell ratios. The kil ling process was not affected by the NADPH oxidase inhibitor diphenyle neiodonium bisulfate, which indicates that recombinant IL-8 stimulates oxygen-independent mycobactericidal mechanisms of granulocytes. IL-8 did not stimulate H2O2 production in granulocytes but primed the cells for enhanced H2O2 production upon stimulation with preopsonized M. fo rtuitum. In sum, the chemokine IL-8 not only is involved in the recrui tment of granulocytes to the site of infection but also facilitates th e elimination of microorganisms by increasing the efficiency of the ba ctericidal activity of granulocytes.