Ivermectin: its effect on the immune system of rabbits and rats infested with ectoparasites.

The influence of subcutaneously administered ivermectin on the specific immune response was studied in rabbits infested with mites (Psoroptes cuniculi) and in rats infested with lice (Polyplax spinulosa). A pronounced specific antibody activity and a change in immunoblotting pattern was observed in rabbits after the ivermectin treatment. However, in rats the antibody activity decreased and the profile of specific antibodies, tested by immunoblotting, remained the same as before the treatment. The specific immune response in rabbits artificially immunized with whole-body Psoroptes cuniculi extract was not affected by ivermectin. It was concluded that ivermectin has no direct effect on the immune response of rabbits and rats and that the enhanced immune response in the mite-infested rabbits was caused by the massive release of antigens associated with the synchronous death of the mites.