Growth
inhibitory effect of bovine lactoferrin to Toxoplasma gondii tachyzoites
in murine macrophages: tyrosine phosphorylation in murine macrophages
induced by bovine lactoferrin.
Tanaka T, Omata
Y, Isamida T, Saito A, Shimazaki K, Yamauchi K, Suzuki N
J Vet Med Sci 1998 Mar 60:369-71
Abstract
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.
Author Address
Department of Veterinary Physiology, Obihiro University of Agriculture
and Veterinary Medicine, Japan.
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