EVALUATION OF PHAGOCYTIC-ACTIVITY IN A TELEOST FISH, DICENTRARCHUS-LABRAX

Following stimulation by bacterial (Aeromonas salmonicida) and fungal (Candida albicans) pathogenic agents, the phagocytic function of the m acrophages of a marine fish, Dicentrarchus labrax, was demonstrated an d analysed by two techniques: light microscopy allowed visualization a nd quantification of this non-specific immune activity, while the kine tics of reactive oxygen intermediate production were analysed by measu rement of luminol-dependent chemiluminescence (CL). The CL of macropha ges isolated from the pronephros provided an indication of the intensi ty of the 'respiratory' or 'oxidative' burst accompanying phagocytosis . The ratio of macrophage: pathogenic agents and the amplitude of the CL response varied with the type of pathogenic agents. Agents isolated from marine organisms activated the phagocytic cells of sea bass more than the same micro-organisms isolated from mammals, and those opsoni sed by fish serum increased the macrophage CL response.