Table 3.
Cross-protective effects in 3-week-old SPF chickens immunized with K40/09 parent, K40/09 HP40 and K40/09 HP50 against challenge with three distinct subgroups of nephropathogenic IBV strain.
| IBV strain immunizeda | Genogroup of challenge virus | IBV strain of challenge virusb | No. of challenge virus isolated/no.of challengedc |
|||
|---|---|---|---|---|---|---|
| Trachea | Kidney | |||||
| Control | Vaccinated | Control | Vaccinated | |||
| K40/09 (Parent) | Korean II subgroup 1 | KM91 | 10/10 | 0/10*** | 10/10 | 2/10*** |
| Korean II subgroup 2 (QX-like) | K1277/03 | 10/10 | 0/10*** | 10/10 | 1/10*** | |
| Korean new cluster 1 | K40/09 | 10/10 | 0/10*** | 10/10 | 0/10*** | |
| K40/09 HP40 | Korean II subgroup 1 | KM91 | 10/10 | 0/10*** | 9/10 | 0/10*** |
| Korean II subgroup 2 (QX-like) | K1277/03 | 10/10 | 0/10*** | 10/10 | 0/10*** | |
| Korean new cluster 1 | K40/09 | 10/10 | 0/10*** | 10/10 | 1/10*** | |
| K40/09 HP50 | Korean II subgroup 1 | KM91 | 10/10 | 0/10*** | 9/10 | 0/10*** |
| Korean II subgroup 2 (QX-like) | K1277/03 | 10/10 | 1/10*** | 10/10 | 0/10*** | |
| Korean new cluster 1 | K40/09 | 10/10 | 0/10*** | 10/10 | 0/10*** | |
a
Three-week-old chickens were immunized with IBV K40/09 parent, K40/09 HP40 or K40/09 HP50 (103.0 EID50/bird) via the intraocular route.
b
At 3 weeks post-immunization, all birds were challenged with 104.5 EID50 of three challenge strains via the intraocular route.
c
Five days after challenge, protection was evaluated by the absence of challenge virus in the trachea and kidney.
***
p < 0.001, by Fisher's exact test, compared to non-vaccinated control group.