This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been retracted at the request of the Editor-in-Chief and Authors.The Editors-in-Chief would like to confirm the retraction of this article at the request of both authors, as it duplicates data that had already appeared in Nitric Oxide, 16 (2007) 294–305, doi:10.1016/j.niox.2006.11.001 and J. Interferon Cytokine Res., 27 (2007) 497–506, doi:10.1089/jir.2007.0166, or had been submitted to International Immunopharmacology, later to appear in Int. Immunopharmacol., 7 (2007) 1403–1413, doi:10.1016/j.intimp.2007.07.004. The authors would like to apologize for this administrative error on their part.