|Event Title||First Global Alliance for Research on Avian Diseases (GARAD) Conference|
|Event Date & Time||On Tue, 30 Jun 2015 at 14:50:00 - 15:05:00|
|Venue||Edmond J. Safra Lecture Theatre|
|Abstract Title||Insights in the tropism of avian viruses: binding profiles and receptor specificity of viral attachment proteins using a novel avian microarray|
|Affiliations||1 Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands|
For avian coronaviruses hardly anything is known about virus-host interactions determining tropism and pathogenicity. To gain insights into both host and tissue tropism of these viruses, we developed a unique avian tissue microarray, comprised of tissues of bird species from the orders Anseriformes and Galliformes. Recombinantly expressed viral attachment proteins were used to profile the binding of S1 proteins of six different avian coronaviruses using protein histochemistry. While S1 of chicken, pigeon and partridge CoVs attached to the respiratory tract of their respective hosts, S1 of turkey, quail, and guineafowl CoVs predominantly bound to intestinal tissues. This binding is in accordance with the reported pathogenicity of these viruses in vivo. Interestingly, the binding of respiratory pathogens required the presence of sialic acids on the tissues, while enteric CoV S1 could still bind to desialylated tissues. To define their glycan specificity, glycan arrays were performed, showing that chicken CoV S1 recognized a specific α2,3-linked disialoside. Blocking studies on tissues revealed that this S1 preferred binding to α2-3 sialic acid subtype I lactosamines. Strikingly, the binding of pigeon and partridge CoV S1 to tissues could not be blocked by this sialylated lactosamine, indicating that these viral attachment proteins have a yet unknown preference for other sialosides. Furthermore, the glycan array revealed that turkey and quail CoV recognize a novel viral attachment factor, namely galactose-N-acetylglucosamine repeats (LacNAc), which could also block the binding of these S1 proteins to tissues. Finally, our tissue array data revealed that both glycan subtypes are expressed on respiratory and gastrointestinal systems of various other avian species. Taken together, our novel tissue array allows profiling the binding of viral attachment proteins of avian coronaviruses, but is also other applicable for research on other avian viruses like influenza.