EN
The effect of chlorfenvinphos (0,0 - diethyl 0-/1-/2', 4'-dichlorphenyl/-2-chlorvinyl phosphate) on immune responses in chickens was investigated. The chickens were given single or repeated doses of chlorfenvinphos and immunized with sheep red blood cells. Immune responses were assayed by the localised haemolysis in gel and by titration of heamagglutinins and haemolysins in serum. Also, the number of germinal centres in the spleen was determined. No immunosuppressive effect of chlorfenvinphos was found in chickens which received the single dose of the compound. On the contrary, the obtained results indicated that the insecticide caused the immune mobilization of the organism. In chickens receiving repeated doses of the compound, all the examined immunological indices were lower as compared with controls.