FIG 2.

rR188I mutation reduces FAdV-4 virulence in SPF chickens. (A) Phylogenetic analysis based on the hexon amino acid sequences. GenBank accession numbers and time periods and geographical regions of virus isolation are indicated in parentheses. Red square, novel FAdV-4 strain; light blue circle, nonpathogenic ON1 strain. (B) Schematic of the generation of mutant viruses. Thirteen amino acids of the rWT-FAdV4 (HLJFAd15) strain hexon protein that were different from the ON1 strain were mutated to the residues of ON1, respectively. The diagrams are not to scale. (C) Survival curve. Thirteen single-amino-acid mutant viruses were injected into 3-week-old SPF chickens. rWT-FAdV-4, rHN20, and mock-injected chickens (control) were the three groups (n = 5). (D) Survival rates after viral challenge. (E) 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.