Table 3.
Seropositivity for anti-H5 HA antibodies in broiler chickens vaccinated with alum-adjuvanted rH5-E. coli or rH5-BEVS.
| Group | Positivity in tests [%] | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
2 weeks post-prime |
4 weeks post-prime |
1 week post-boost |
2 weeks post-boost |
|||||||||
| iELISA | HI | iELISA | HI | iELISA | FluAC | FluAC | HI | iELISA | FluAC | FluAC | HI | |
| + | + | + | + | + | + | +/– | + | + | + | +/– | + | |
| B-25/2# | 100# | 0# | n/a | n/a | n.d. | n.d. | n.d. | n.d. | 100 | 0 .. | 0 .. | 0# |
| B-25/4# | 87.5# | 0# | 50# | 37.5# | 100# | 25# | 12.5# | 25# | 100# | 33 | 33 | 37.5# |
| B-25_ref/2* | 86* | 0* | n/a | n/a | n.d. | n.d. | n.d. | n.d. | 86* | 0* | 0* | 0* |
| B-25_ref/4# | 100# | 25# | 50# | 25# | 100# | 50# | 0# | 12.5# | 100# | 50# | 25# | 12.5# |
Four groups of 1-week-old broiler chickens in Exp 1 were vaccinated twice at 2- and 4-week intervals with 25 μg of the test (rH5-E. coli) or reference (rH5-BEVS) antigens and aluminum hydroxide (alum) adjuvant. The test vaccine groups were denoted according to the chicken type (B, broiler), the tested or reference antigen dose in μg (25 or 25_ref), and the time interval between doses in weeks (2 or 4). Post-vaccination sera were analyzed for the presence of anti-H5 HA antibodies using the indirect and competitive ELISAs, H5 iELISA and FluAC H5, respectively, and a hemagglutination inhibition (HI) assay with H5N2 low-pathogenic (LP) AIV. Tests were performed and interpreted as described in the Materials and Methods section. Data are presented as the percentage of chickens positive (+) in iELISA and HI tests, and positive (+) or doubtful (+/−) in the FluAC test at the indicated sampling time points. The #, *,”, and .. symbols following the seropositivity percentages denote that 8, 7, 6, or 5 chickens were tested, respectively, in the group comprising 8 (#) or 7 (*) chickens.