Effect of levamisole on the lymphocyte and macrophage activity in carp (Cyprinus carpio).

Levamisole, an anthelminthic drug which is often used in cattle, is known for its immunomodulatory effect in several species. In the present work we investigated the in vitro effects of different concentrations of levamisole on lymphocyte proliferation with mitogen in carp. At low concentrations, ie 12.5 to 0.1 micrograms/ml, levamisole stimulated proliferation with phytohemagglutinin P (PHA-P) and Con A, had no effect at medium concentrations and acted as a suppressor at high concentrations, ie 100 micrograms/ml PHA-P and 100 to 10 micrograms/ml for Con A. Spleen and kidney macrophages were in contact with levamisole for 2 h before phagocytosis of opsonised Yersinia ruckeri. Doses of 200 and 100 micrograms/ml were found to be suppressive, whereas 6.2-0.8 micrograms/ml were stimulatory, as observed by chemiluminescence.