Immunotoxicity of sub-chronic doses of diazinon in male albino Wister rats

Diazinon is one of the most organophosphate pesticides that widely used in agriculture. In the current study, diazinon was administrated at doses of 10, 1, 0.1mg/kg and different humoral and cell mediated immunity parameters were examined in male Wister rats. Results showed that high dose of diazinon (10mg/kg) could inhibit the hemagglutination titer, the total serum immunoglobulin, quantitative hemolysis of SRBC (QHS), phagocytic function of neutrophils, delayed-type hypersensitivity response, proliferative response of the blood mononuclear cell and decrease the percentage of CD4+ and CD8+ blood mononuclear cells without affecting CD4/CD8 ratio significantly. Diazinon at moderate dose (1mg/kg) show only reduction in QHS, phagocytic function of neutrophils and delayed-type hypersensitivity response. Diazinon at low dose (0.1mg/kg) did not produce any significant changes on the humoral and cellular immune tested parameters. In conclusion high dose of diazinon affect both humoral and cell-mediated immunity in rats. On contrary, low dose of diazinon has no adverse effect on the immune response.