Table 4. Immunogenicity of A/Vietnam/1203/04 ΔH5 HA recombinant viruses in ferrets.
| HI titer of sera after immunization with:
|
||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Virus | ΔH5/04 | ΔH5S155→N, T156→A/04 | ΔH5S120→N/04 | ΔH5S223→N/04 | ||||||||
| ΔH5N1/03 | 20 | 20 | 10 | 160 | 80 | 160 | 20 | 20 | 10 | 20 | 10 | 10 |
| ΔH5/04 | 20 | 20 | 20 | 20 | 20 | 20 | 20 | 20 | 20 | 20 | 20 | 20 |
| ΔH5S155→N, T156→A/04 | 20 | 10 | 20 | |||||||||
| ΔH5S120→N/04 | 80 | 80 | 20 | |||||||||
| ΔH5S223→N/04 | 160 | 320 | 320 | 160 | 320 | 160 | 320 | 320 | 320 | 640 | 640 | 640 |
Eleven-week-old influenza-seronegative ferrets were vaccinated twice at 3-week intervals by intramuscular injection of inactivated, purified, and concentrated virus preparation containing 7 μg of HA in 250 μl of PBS. Data are the HI titers from three ferrets are presented individually. HI tests used 0.5% chicken RBCs. Homologous titers are underlined.