Preparation of polyclonal anti-NDV chicken antisera
Four reference NDV strains, clone30, Ulster, R151/94, and R1468/12, representing the avian orthoavulavirus-1, 2.II, 2.VI (PPMV-1) and 2.VII.1.1, respectively, were selected for preparation of polyclonal anti-NDV chicken antiserum in the FLI animal facility. Viruses were first inactivated by betapropiolactone (Sigma; 0,05%,) treatment and 0.5 mL of each virus was injected in four 4-week-old-SPF White Leghorn chickens via subcutaneous route after mixing with Freund’s complete adjuvant (1:1). A second immunization shot was given after 4 weeks. Collection of serum was performed at 7 days after the booster immunization, followed by inactivation at 56°C for 30 min and stored at -20 °C until further use. Immunizations were carried out in accordance with the legally approved protocol (MV-LALLF- 7221.3-2.5-010/10).