Immunotoxicity of avermectin on Kunming mice

Objective To measure the impact of avermectin on the cellular immunity, humoral immunity and nonspecific immunity of Kunming mice. Methods The subject mice were assigned to the experimental groups to receive avermectin at doses of 20, 10, 5 mg/kg for 28 days and a blank control group. The cellular immunity was evaluated in terms of T lymphocyte proliferation and delayed type hypersensitivity (DTH), the humoral immunity estimated with plaque forming cell assay (PFC) and half hemolysis value method (HC50), and the nonspecific immunity measured based on peritoneal macrophages phagocytosis for chicken red blood cells, carbon clearance test and NK cell activity. Results At a dose of 20 mg/kg, the T lymphocyte proliferation was 0.76 (in contrast to 0.86 in the negative control), the half hemolysis value 128.45 (versus 140.96 in the negative control), and the PFC 89.21×106 (versus 113.33×106). In the 20 mg/kg and 10 mg/kg medication groups, the carbon clearance indices were 5.59 and 5.61 (versus 7.96), and the peritoneal macrophage phagocytosis levels for chicken red blood cells were 0.86 and 0.90 (versus 1.05). Reduction was observed in all of the above function indicators compared to the control group, with significant difference (P0.01). Conclusion Avermectin inhibits the celluar immunity, humoral immunity and nonspecific immunity of Kunming mice.