FIG 3.

rI188R mutation confers rHN20 virulence in SPF chickens. (A) Detailed schematic representation of the four recombinant viruses. rWT-FAdV4, rescued wild type FAdV-4; rHN20, the hexon gene was replaced with the ON1 sequence; rI188R, amino acid 188 of the hexon protein from the rHN20 strain was reverse mutated to wild type; rR188I, amino acid 188 of the hexon protein of the rWT-FAdV4 strain was mutated to the ON1 sequence. (B) Virus growth curves of the four viruses in LMH cells. (C) Survival curve. The four viruses were intramuscularly injected into 3-week-old SPF chickens (n = 10). (D) Viral load in the liver in different groups (n = 3). Error bars represent the SEM. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ns, not significant. (E) Histological examination of the liver, spleen, and bursa. Scale bar, 50 μm.