Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 12, 2012
Publication Date: April 4, 2012
Citation: Kapczynski, D.R., Zsak, A., Ewald, S., Suarez, D.L. 2012. Difference in susceptibility to highly pathogenic avian influenza virus following interferon alpha application in chickens expressing polymorphism in the chicken Mx gene [abstract]. 8th International Symposium on Avian Influenza. Available: http://vla.defra.gov.uk/news/new_isai12.htm Technical Abstract: Type I interferons, including interferon alpha (IFN-a), represent a first line of defense initiated by the innate immune response following viral infection. Induction of IFN-a results in an antiviral state which can decrease morbidity and mortality. In response to IFN-a, host cells produce a myriad of anti-viral proteins, including Mx, which has been shown to confer protection against influenza in mammalian studies. Chickens have a single Mx gene with multiple alleles. In previous experiments, transfecting cDNAs of various alleles into mouse 3T3 cells, a single nucleotide polymorphism encoding an Asn631Ser dimorphism in the chicken Mx protein determined antiviral activity against highly pathogenic avian influenza virus (HPAIV). Mx-Asn631 was antivirally positive in transfection experiments, whereas the Mx-Ser631 alleles lacked antiviral activity. We have previously demonstrated the protective potential of IFN-a applied to poultry against low pathogenic avian influenza viruses. In those studies, intranasal application of IFN-a during infection reduced clinical signs of disease and the incidence of viral shedding. In these studies, we evaluated the Mx-631 dimorphism on pathogenesis of HPAIV H5N1 in specific pathogen free (SPF) chickens that segregate for Mx-631 alleles during IFN-a application. We observed >90 percent protection from mortality that was dependent on Mx-631 allele. Birds with the Mx-Asn631 (White Leghorn) were resistant to disease whereas Mx-Ser631 birds (White Rock) were susceptible to HPAIV. Results of virus shedding and antibody responses will be discussed. Taken together, these studies show that IFN-a can protect chickens from disease associated with HPAIV and that Mx may contribute to that protection.