TABLE 2.
SAA levels after challenge of vaccinated and control calves with wild-type strain 85020a
| Time after challenge (h) | Mean SAA (μg/ml) ± SEM (no. of surviving calves)
|
||
|---|---|---|---|
| Vaccinated i.m. | Vaccinated i.n. | Controls | |
| 0 | 13.1 ± 7.3 (4) | 2.2 ± 0.7 (4) | 65.2 ± 37 (3) |
| 10 | 21.8 ± 8.1 (4) | 28.8 ± 3.1 (4) | 72.3 ± 17 (3) |
| 23 | 37.0 ± 15.6 (4) | >157.6 (1) | >157.6 (1) |
| 47 | 29.2 ± 12.8 (4) | >157.6 (1) | 91.1 (1) |
| 71 | 22.7b (4) | >157.6 (1) | −c |
| 143 | 12.6 ± 8.1 (4) | − | 12.5 (1) |
| 167 | 4.5b (4) | 5.9 (1) | − |
a
Two groups of four calves each were vaccinated twice, at a 4-week interval, either i.m. or i.n., with the aroA mutant strain, and a group of three calves were left unvaccinated as controls. Two weeks after the second vaccination, the animals were challenged with the wild-type strain. SAA levels were determined in sera collected on the day of challenge (day 42) and at intervals thereafter.
b
Only one serum sample was assayed.
c
No sample available.