Effects of the organochlorines p,p′-DDE and lindane on gilthead seabream leucocyte immune parameters and gene expression

Toxicological effects of pesticides in water-living animals are very important, especially when these animals are for human consumption. Thus, in vitro tests were performed to evaluate the immunotoxicological impact of two organochlorines, lindane and p,p'-DDE, on gilthead seabream (Sparus aurata L.) leucocytes, an economically important fish-farmed species in the Mediterranean area. Leucocyte viability (apoptosis and necrosis), innate immune parameters (phagocytosis, respiratory burst and cell-mediated cytotoxicity) and immunerelevant gene expression were determined after incubation of head-kidney leucocytes with the pesticides (0 - control, 5 ng to 50 mu g ml(-1) for 4 or 24 h). These pesticides had no negative effects on leucocyte viability and produced very slight variations in the immunological parameters. However, both p,p'-DDE and lindane up-regulated to varying degrees some immune-related genes such as IL-1 beta, TNF alpha, MHCI alpha, MHCII alpha, Mx, TLR9, IgML and TCR alpha. Further studies are needed to ascertain how pesticides affect the immune system of farmed fish and the mechanisms involved. (C) 2008 Elsevier Ltd. All rights reserved.