DIFFERENTIAL-EFFECTS OF CHLORINATION OF BACTERIA ON THEIR CAPACITY TOGENERATE NO, TNF-ALPHA AND IL-6 IN MACROPHAGES

Activated rodent macrophages produce high amounts of nitric oxide (NO) . NO as a tumoricidal and defence molecule against intracellular paras ites is commonly accepted. However, its role as an obligatory killing factor for extracellular bacteria is controversial. In the present stu dy we stimulated murine peritoneal macrophages by heat-killed bacteria (Staphylococcus aureus, S. epidermidis and Escherichia coli). In some groups bacteria were pretreated with HOCl, to replace the chlorinatin g system in activated neutrophils that operates as a bactericidal syst em in vivo. High levels of NO, tumour necrosis factor-alpha (TNF-alpha ) and interleukin-6 (IL-6) were detected after stimulation by all non- chlorinated bacteria strains tested. However, after chlorination Gramp ositive bacteria lost their ability to induce NO and TNF-alpha, wherea s phagocytosis and IL-6 production were not affected by chlorination.