Selenium supplementation enhances the protective response to Toxocara canis larvae in mice

The effect of oral and intraperitoneal supply of sodium selenite on the immune response to, and the course of T. canis larvae infection in mice were determined. The number of worms in the host tissue was reduced but the migratory route of larvae was not affected. Selenite (Se) supplementation influences Se retention in the liver, enhanced IL-5 and eosinophil responses and evoked IL-6 production in mice infected with T. canis. The enhanced protection in mice given Se intraperitoneally was associated with high levels of parasite-specific IgE, and enhanced concentration of Th1-related cytokines such IL-12p70, TNF-alpha and IFN-gamma. In mice given Se orally, the predominant cytokines produced were IL-10, MCP-1 and IL-6 and these mice had lower protection. In conclusion, Se supplementation increases production of specific cytokines in mice infected with T. canis and increases protection against infection.