Modulatory effects of Pb2+ on virally challenged chicken macrophage (HD‐11) and B‐lymphocyte (DT40) cell lines in vitro

Elevated levels of lead have been found in waterfowl, due to human activities. Lead may cause immunomodulatory effects, but the mechanisms are largely unknown, especially upon viral challenges. To characterize avian immunomodulatory hazards of Pb(2+) , we used chicken macrophage (HD-11) and B-lymphocyte (DT40) cell lines, as in vitro models for the innate and adaptive immune system respectively. The cells were activated via toll-like receptor-3 (TLR3) by polyinosinic-polycytidylic acid sodium salt (poly I:C), mimicking viral infections. Our results indicate that Pb(2+) is cytotoxic to both cell lines, macrophages being more sensitive. De novo synthesis of glutathione (GSH) plays an important role in protecting macrophages from Pb(2+) intoxication, which might also be closely involved in the induction of nitric oxide upon Pb(2+) exposure. Stimulatory effects on cell proliferation were noticed at non-cytotoxic Pb(2+) concentrations as well. Pb(2+) exposure could also affect the inflammatory status by inhibiting the pro-inflammatory interferon (IFN)-gamma while promoting the anti-inflammatory type I IFNs production in both macrophages and B-cells, and increasing intracellular IgM levels in B-cells. These results suggest that the immunomodulatory effects of Pb(2+) in birds are probably closely associated with the disruption of immune cell proliferation and cytokine production, potentially causing disorders of the avian immune system. This article is protected by copyright. All rights reserved.