Molecular identification and characterization of turkey IFN-gamma gene

The cDNAs of turkey and chicken interferon gamma (IFN-gamma) were cloned and the functional activity of turkey and chicken IFN-gamma was compared. The coding region of turkey IFN-gamma gene encodes a predicted mature protein of 145 amino acids with a molecular weight at 16.8 kDa. Compared with type I IFN, the IFN-gamma between turkey and chicken also had the same size and high degree of identity at the nucleotide (96.0%) and amino acid (96.4%) sequence. Turkey IFN-gamma was cross-reactive with chicken cells. Both turkey and chicken IFN-gamma could induce production of nitric oxide by turkey or chicken macrophages. Turkey IFN-gamma also had similar degree of sensitivity to heat and pH 2.0 as chicken IFN-gamma. The functional activity of both turkey and chicken IFN-gamma could be neutralized by a monoclonal antibody specific to chicken IFN-gamma to a similar extent. These results indicated that IFN-gamma protein was cross-reactive between turkey and chicken.