Suppression of cellular immune responses in BALB/c mice following oral exposure to permethrin

The immunotoxic potential of permethrin was studied in BALB/c female mice. The mice were administered 0, 0.4, 0.04, or 0.004 mg/kg body weight/d of permethrin in corn oil over a 10-d period. The mice were then sacrificed, and lymphoproliferative assays were performed, and cytotoxic T lymphocyte activity was measured in splenocytes. Results indicated that, in the highest dose group, unidirectional mixed lymphotic responses were significantly reduced. Reductions in blastogenesis were observed at all permethrin doses, indicating an alteration in the ability of T lymphocytes to recognize and respond to foreign antigens. Natural killer activity was also reduced by permethrin exposure, as was the cytotoxic activity of T lymphocytes. Overall results indicated that functions requiring specific antigen recognition and/or effector function were decreased, while nonspecific mitogen stimulations and body and organ weights were not affected by permethrin exposure.