Abstract

Reactive oxygen intermediate (ROI) production by macrophages is one indication of the immune status of an animal. We are currently characterizing the ability of macrophages to produce intracellular superoxide in fish which have been infected with Mycobacterium marinum. Fish were given a dose 10*7 CFU M. marinum by intraperitoneal injection and sacrificed at various time periods following injection. The reduction of NBT by cells stimulated with PMA showed that there was a marked stimulation of ROI production of 200-300% of control levels in M. marinum infected fish for up to 6 weeks following the injection. In spite of this enhanced production of ROI'S, we have been able to consistently recover bacteria from multiple organs of the experimental fish. This may indicate that the microorganism has developed mechanisms to escape oxidative injury.