Infect Immun. 2009 Jul 20. [Epub ahead of print]
Indoleamine 2,3-dioxygenase is involved in the defense against Neospora caninum in human and bovine cells
Spekker K, Czesla M, Ince V, Heseler K, Schmidt SK, Schares G, Däubener W.
Institute of Medical Microbiology and Hospital Hygiene, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany; Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, D-16868 Wusterhausen, Germany.
Neospora caninum is an apicomplexa parasite closely related to Toxoplasma gondii. In nature this parasite is found especially in dogs and cattle, but may also infect other livestock. As an obligate intracellular parasite, Neospora caninum growth is mainly controlled by the cell-mediated immune response. During infection the cytokine interferon-gamma (IFN-gamma) plays a prominent role in regulating the growth of Neospora caninum in natural and also experimental diseases. The present study indicates that the induction of the tryptophan-degrading enzyme indoleamine 2,3-dioxygenase (IDO) is responsible for the inhibition of parasite growth, mediated by IFN-gamma activated bovine fibroblasts and endothelial cells. This antiparasitic effect could be abrogated by the supplementation of tryptophan as well as by the IDO-specific inhibitor 1-L-methyltryptophan. In conclusion, our data show that human and bovine cells use the identical effector mechanism to control the growth of Neospora caninum.
PMID: 19620347 [PubMed - as supplied by publisher]