... were as follows: 50°C for 2 min, 95°C for 10min, 40 cycles of 95°C for 15 s and 60°C for 1 min, fol-lowed by one cycle of 95°C for 15 s, 60°C for 15 s and 95°C for 15 s. The final step was to ... of pathogenicity and mortality in chickens, whereas sero-type 2 is avirulent in chickens [3]. Based on virulence,serotype 1 strains are classified as classically, intermedi-ate, very or hypervirulent ... difference in theexpression levels of cytokines was possibly influenced bythe different degree of viral replication. However, factorsinfluencing the timing of cytokine regulation in bursaltissues and...