IMMUNO-MODULATOR EFFECTS OF CARBARYL AND 2,4-D IN THE EARTHWORM EISENIA-FETIDA-ANDREI

Carbaryl and 2,4 dichlorophenoxy acetic acid (2,4 D) exerted different ial effects on the earthworm E. f. andrei functions related to immune defense. As determined by contact test assay, carbaryl activity is cha racterized by a low LC50 value of 3.4 mu g/cm(2), compared to 18 mu g/ cm(2) for 2,4 D. Incubating earthworms with doses of carbaryl as low a s 0.1 mu g/cm(2) resulted in the inhibition of the lysozyme activity d etected in the cytosol (CL). A strong inhibition of phagocytosis was a lso obtained but with 1.5 mu g/cm(2). On the other hand, low doses of carbaryl significantly stimulated cytolysis (0.1 mu g/cm(2)), serine p rotease activity (0.1 mu g/cm(2)) in the coelomic fluid (CF) and serin e protease activity in the CL (0.05 mu g/cm(2)) Concerning 2,4 D, both cytolysis in the CF and serine protease activity in the CL were stimu lated by respectively 3.5 mu g/cm(2) and 18 mu g/cm(2) Phagocytosis wa s inhibited only with 18 mu g/cm(2). Lysozyme and serine protease inhi bitor activities were not affected. The immune toxicological assays we developed in earthworms, allow to distinguish between chemicals with different immuno-modulatory properties. Moreover, earthworms appear to be a particularly well adapted sentinel organism for the evaluation o f soil contamination.