Growth Inhibitory Effect of Bovine Lactoferrin to Toxoplasma gondii Tachyzoites in Murine Macrophages: Tyrosine Phosphorylation in Murine Macrophages Induced by Bovine Lactoferrin

摘要

References(12) Cited-By(3) Previous studies have shown that lactoferrin induces growth inhibitory effects in mouse macrophages against intracellular Toxoplasma gondii, and these effects were not mediated by the oxygen-dependent and inorganic nitrogen-dependent pathway. To clarify the mechanism of anti-Toxoplasma gondii activity induced by lactoferrin, we examined whether lactoferrin promoted the phosphorylation of tyrosine residues in macrophage proteins. In immunoblotting assays using anti-[phosphorylated tyrosine] monoclonal antibody, phosphorylation of tyrosine residues was detected in protein(s) of approximately 30 kDa in macrophages incubated with lactoferrin. Inhibition of the lactoferrin-induced tyrosine-phosphorylation by genistein led to loss of the lactoferrin-induced growth inhibitory effect against the parasites. These findings suggest that lactoferrin induces tyrosine-phosphorylation in macrophages, and the tyrosine-phosphorylation seems to be associated with the induction of the growth inhibitory activity exerted against intracellular Toxoplasma gondii.