EFFECTS OF FLUORANTHENE ON THE IMMUNOCOMPETENCE OF THE COMMON MARINE MUSSEL, MYTILUS-EDULIS

The effects of a model polycyclic aromatic hydrocarbon on the immunoco mpetence of the marine mussel, Mytilus edulis, were demonstrated in la boratory-controlled experiments. Haemolymph from mussels, exposed for 7 days to three concentrations of fluoranthene, was extracted and assa ys carried out to investigate total and differential haemocyte numbers , peroxidase and phenol oxidase activity, production of reactive oxyge n metabolites and release of lysosomal enzymes. Fluoranthene exposure at 200 and 400 mu g l(-1) resulted in an increase in the total number of circulating haemocytes but did not affect proportions of eosinophil ic to basophilic blood cells. The release of reactive oxygen metabolit es was also significantly stimulated. The percentage of haemocytes exh ibiting peroxidase and phenol oxidase activity increased significantly at the highest contaminant concentration. The release during phagocyt osis of chymotrypsin-like enzyme from the haemocytes was inhibited at all fluoranthene levels. The observed effects on immunocompetence of t he mussel, on exposure to environmentally realistic levels of contamin ant, demonstrate the necessity for further work in order to establish a relationship between pollutants and disease susceptibility. The vari ability in effects on different aspects of the immune response emphasi ses the need for a multi-assay approach to pollution monitoring.