ELSEVIER Toxicology 120 (1997) 231-242 Prenatal exposure to cypermethrin modulates rat NK cell cytotoxic functions G. Santoni ‘,*, F. Cantalamessa a, L. Mazzucca a, S. Romagnoli a, M. Piccoli b a zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Institute of Pharmacology, University of Camerino, Via Scalzino 3, 62032 Camerino, Italy b Department oj Experimental Medicine and Pathology, University “La Sapienza “, Viale Regina Elena 324, 00161 Rome, Italy Received 22 July 1996; accepted 22 February 1997 zyxwvutsrqponmlkjihgfedcbaZYXWVUT Abstract The synthetic pyrethroid insecticide, cypermethrin, was given during gestation to pregnant rats by gavage in corn oil. Peripheral blood and spleen cytotoxic activity of dams and their offspring were then evaluated at different times (30, 60, 90, 120 days) after birth. Pups showed a significant increase in peripheral blood natural killer (NK) and antibody-dependent (ADCC) cytotoxic activity paralleled with a similar increase in the percentage of zyxwvutsrqponmlkj NK-RPl + cells and decreased activity in the spleen. Pregnant cypermethrin-exposed dams showed no changes in peripheral blood or spleen cytotoxic function during the postnatal period. Overall, these results suggest that immunomodulation of cytotoxic activity observed in the offspring is likely attributable to a specific effect of cypermethrin administered during the prenatal period. 0 1997 Elsevier Science Ireland Ltd. Keywords: Developmental immunotoxicity; Insecticide; Pyrethroid; Cypermethrin; Natural killer cells; Cytotoxicity 1. Introduction The ability of natural or synthetic agro-chemi- cals and other environmental chemicals to affect immune responses has aroused considerable inter- est. Traditional methods for toxicological assess- ment have indicated that the immune system is a frequent target of toxic insult following acute, * Corresponding author. subchronic or chronic exposure to xenobiotics (Luster et al., 1988; 1992; Lebrec et al., 1993). Some of these chemicals, especially insecticides are encountered by the organism over a long period of time through the food chain. Continu- ous exposure to these chemicals may increase the susceptibility to various diseases due to immunity failure. Pyrethroids represent one of the most potent insecticides in current use (Aldridge, 1990; Ray, 1991). These substances are essentially sodium 0300-483X/97/$17.00 0 1997 Elsevier Science Ireland Ltd. All rights reserved. PII SO300-483X(97)03662-7