This collaborative project is to evaluate the interaction of avian influenza viruses with the chicken interferon (IFN) system in primary chicken embryonic cells that are highly responsive to: (1) the production of IFN upon infection with avian influenza viruses, and (2) the action of IFN against these same viruses.
APPROACH: A broad spectrum of low pathogenic avian influenza viruses will be evaluated for the ability to induce and resist the action of interferon in chicken cells under standardized cell culture conditions. The generation and analysis of standard IFN induction dose (multiplicity)-response (IFN yield) curves permits an accurate assessment of the maximum IFN-inducing capacity of each influenza virus isolate along with a measure of the number of particles in the virus preparation that contribute to the yield of IFN. These data will be compared with sequences of the NS1 protein in particular to correlate the genetic and phylogenetic characteristics of the viruses relative to IFN induction and action. Two phenotypes of these viruses can be measured: (1) IFN-inducing particle [IFP] activity, and (2) IFN induction-suppressing activity. The genetic information from sequencing will be evaluated to seek meaningful relationships between genotype and phenotypic expression as phylogenetic markers.