Jump to Main Content
Expression of interferon gamma by a highly virulent Newcastle disease virus decreases its pathogenicity in chickens
- Susta, Leonardo, Cornax, Ingrid, Diel, Diego G., Garcia, Stivalis Cardenas, Miller, Patti J., Liu, Xiufan, Hu, Shunlin, Brown, Corrie C., Afonso, Claudio L.
- Microbial pathogenesis 2013 v.61-62 pp. 73-83
- Newcastle disease virus, antiviral properties, chickens, death, disease severity, genome, green fluorescent protein, immunomodulation, interferon-gamma, mortality, pathogenesis, pathogenicity, protective effect, viral antigens, virus replication, viruses
- Infection of chickens with highly virulent NDV results in rapid death, which is preceded by increased expression of interferon gamma (IFN-g) in target tissues. IFN-g is a cytokine that has pleiotropic biological effects including intrinsic antiviral activity and immunomodulatory effects. Here we assessed the effects of IFN-g on NDV pathogenesis in chickens. For this, the coding sequence of chicken interferon gamma was inserted in the genome of the highly virulent NDV strain ZJ1 (rZJ1-IFNg), and the effects of IFN-g expression were determined in vivo by comparing the pathogenesis of rZJ1-IFNg with a control virus expressing the green fluorescent protein (rZJ1-GFP). Expression of IFN-g decreased the intra cerebral pathogenicity index (ICPI) of rZJ1-IFNg, when compared to the control rZJ1-GFP. Additionally rZJ1-IFNg presented a marked decrease in pathogenicity in 4-week-old chickens, as evidenced by lower mortality rates, decreased disease severity, viral shedding, and antigen distribution. These results suggest that early expression of IFN-g during viral replication has a protective effect against virulent NDV infection in chickens, and further suggests that the level and time of expression of IFN-g are critical for the disease outcome.