Emerging
pathogenic viruses, such as avian influenza, pose a constant threat to both the
poultry industry and to human health. To prevent these infections more
effective treatment options are required, therefore, we need to develop our
understanding of the immune response. Interferons (IFN) are rapidly induced
following viral infection and are reported to activate hundreds of IFN
stimulated genes (ISG), which display diverse antiviral activities.
Nevertheless, the majority of these ISGs remain largely unidentified and
uncharacterized in chickens. Here we report the characterization of two ISGs,
viperin and ZAP, in the chicken. We found that structurally both ISGs are
similar to their mammalian counterparts with viperin exhibiting over 70% and
ZAP displaying up to 59% sequence similarity. In vitro analysis of the expression of these ISGs showed that
viperin was rapidly and robustly induced in response to a number of viral and
bacterial stimuli with a kinetic very similar to that of Mx, a commonly
measured ISG. However, following stimulation ZAP’s profile was minimal. In vitro analysis of avian influenza
infected chickens showed that both viperin and ZAP were up-regulated, with
viperin displaying 25- and 150-fold increases whereas ZAP was modestly elevated
at 12- and 10-fold, in the lung and spleen, respectively. Taken together, these
studies help to broaden our understanding of the chicken innate immune
response, which could lead to the development of better therapeutics in the
future.