Differential nitric oxide production by chicken immune cells.

Nitric oxide is a rapidly reacting free radical which has cytotoxic effects during inflammatory responses and regulatory effects as a component of signal transduction cascades. We quantified the production of nitrite, a stable metabolite of nitric oxide, in chicken heterophils, monocytes and macrophages after stimulation by IFNgamma, LPS and killed bacteria. Our results demonstrate a differential production of nitrite over 72 h by chicken peripheral blood heterophils, monocytes and the chicken macrophage cell line (HD11). HD11 cells produced an average of 10 fold more nitrite in comparison to monocytes and 30 fold more than heterophils upon stimulation. This production could be inhibited by S-methylisothiourea indicating that the inducible nitric oxide synthase enzyme was participating in the pathway leading to nitrite production.