Submitted to: American Association of Veterinary Parasitologists Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/1997
Publication Date: N/A
Technical Abstract: Coccidiosis which is caused by several species of Eimeria, severely damages the gut and results in greater than $600 million annual economic losses. To identify various immune factors which control parasite survival, the roles of interferon-gamma (IFN-gamma) and nitric oxide (NO) were investigated in E. tenella infection. Recombinant chicken IFN-gamma (rchIFN-gamma) was expressed in CHO cells and used in in vitro studies. Pretreatment of chicken fibroblast cells with rchIFN-gamma caused a significant inhibition of E. tenella development. Since IFN-gamma-mediated induction of NO has been shown to play a critical role in some intracellular parasitic infections, the role of NO was studied by inhibiting in vivo induction of the NO pathway using S-methyl isothiourea sulfate (SMIT), a potent and selective inhibitor of inducible nitric oxide synthase. SMIT-treatment did not alter the levels of oocyst production, weight loss and intestinal lesions compared to untreated control following E. tenella infection. These results indicate that NO is not involved in protective host response to E. tenella infection. (Supported partly by NRI Grant #91-37204-6358).