Spinosad: Sub-acute immunotoxicity studies in mice

In the present study, the immunological alterations induced by spinosad were assessed by measuring effects on sub-acute exposure of spinosad on humoral immune response and cell mediated immune response in Swiss albino male mice. The serum antibody titer against sheep RBCs (SRBC) was measured by haemagglutination (HA) test to assess the effect of spinosad treatment on humoral immune response.The results of HA test indicated significant effect on antibody titer against SRBC. There was progressive and proportionate decrease in antibody titer, significant decrease at both dose levels of spinosad treatment.The effect on cellular immune responsewas assessed with the help of two important parameters, Phytohemagglutinin (PHA) induced lymphocyte proliferation assay and delayed type hypersensitivity (DTH) response to SRBC.Stimulation index (S.I.) of lymphocyte proliferation assay did not show any biologically significant difference in spinosad treated groups as compared to saline treated group.DTHresponse to SRBC was characterized by mild to moderate inflammatory reaction, with erythema, edema, swelling in saline treated mice group.The findings of DTH response clearly indicate that spinosad has mild immunotoxic effect at higher dose i.e. 58 mg/kg/day; i.p. and has mildly suppressed DTH response at this dose level.