GENERATION OF REACTIVE OXYGEN SPECIES BY BLOOD MONOCYTES DURING ACUTEPLASMODIUM-KNOWLESI INFECTION IN RHESUS-MONKEYS

The status and kinetics of monocyte activation during acute Il knowles i infection was investigated by latex-induced, luminol-dependent chemi luminescence (CL) response. The contribution of various reactive oxyge n species (ROS) to CL response was estimated before infection and at p eak parasitaemia (day 7 post infection) by using scavengers of ROS (be nzoate, catalase and superoxide dismutase). The chemiluminescence inde x (CLI) was not found to be significantly different from controls on d ay 2 postinfection, but was significantly higher on days 5 and 7 posti nfection. Hydroxyl radical (OH.) production was considerably elevated, whereas superoxide anion(O2(-.)) and hydrogen peroxide (H2O2) product ion dropped following infection. These changes in generation of ROS ar e discussed in relation to the progression of parasitaemia to high lev els, immunopathology and immunosuppression during acute P knowlesi inf ection.