INVESTIGATION OF FACTORS INFLUENCING THE ABILITY OF RENIBACTERIUM-SALMONINARUM TO STIMULATE RAINBOW-TROUT MACROPHAGE RESPIRATORY BURST ACTIVITY

The early stages of contact between Renibacterium salmoninarum and rai nbow trout macrophages were investigated. Live R. salmoninarum elicite d a respiratory burst, which was enhanced by heat-killing the microorg anism. This phenomenon, though, was not observed using UV killed bacte ria. Both responses were enhanced when a combination of LPS and TNF al pha was used to activate the macrophages prior to contact with R. salm oninarum. Further studies demonstrated that both compounds synergised to enhance O-2(-) production, and that this was correlated with the ab ility to kill the pathogen. Opsonisation of R. salmoninarum with serum factors also increased the respiratory burst, but no difference was f ound between normal serum and heat-inactivated serum. (C) 1997 Academi c Press Limited.