Human and murine IFN-b and human IFN-l (IL-29) were purchased from PBL InterferonSource (Piscataway, NJ). Recombinant porcine IFN-a1 [24] was kindly provided by Nicolas Ruggli (IVI, Mittelhä usern, Switzerland). Recombinant chicken IFN-a [25] was kindly provided by Peter Stä heli (University of Freiburg, Germany). Canine IFN-b [26] was kindly provided by Philippe Plattet (Department of Clinical Research and Veterinary Public Health, University of Bern).