1. Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell’Università 10, 35020 Legnaro, Italy
2. Department of Biological Chemistry, University of Padova, Via G. Colombo 3, 35131 Padova, Italy
3. Department of Immunotechnology, BMC D13, Lund University, 221 84 Lund, Sweden