TABLE 2.
Chicken pathogenicity of persistently infecting isolates and recombinants with a substitution in F and/or HN
| Virus | FPCSa | HN residue 169 | ICPIb |
|---|---|---|---|
| rNDV | HNRTKR/F117 | G | 0.13 |
| NDVpi-P12 | HNRTKR/S117 | R | 0.0 |
| NDVpi-P18 | HNRTKR/S117 | R | 0.1 |
| rNDV-F117S | HNRTKR/S117 | G | 1.05 |
| rNDV-G169R | HNRTKR/F117 | R | 0.20 |
| rNDV-F117S/G169R | HNRTKR/S117 | R | 0.25 |
a
FPCS, F protein cleavage sequence. The substituted residue is in boldface.
b
Intracerebral pathogenicity index (ICPI) of each virus was determined in 1-day-old pathogen-free chicks. A strain with an ICPI value of <0.7 is attenuated and not considered as a select agent.