TABLE 2.
ELISA IgG antibody responses to NS1 antigen in sera of chickens and turkeys after inoculation with live or inactivated influenza A viruses
| Treatmenta | Inoculation routeb | Vaccine type | Viral inoculum | ELISA reaction to NS1 with serum dilutedc:
|
|
|---|---|---|---|---|---|
| 1:100 | 1:200 | ||||
| Normal chicken serum | − | − | |||
| Sham vaccination | s.c. | − | − | ||
| TW/68 (H5N9) (1)d | s.c. | Purified | Inactivated | − | − |
| TW/68 (H5N9) (2) | s.c. | Purified | Inactivated | − | − |
| TW/68 (H5N9) (3) | s.c. | Purified | Inactivated | − | − |
| CP/97 (H7N2) (1) | s.c. | Purified | Inactivated | − | − |
| CP/97 (H7N2) (2) | s.c. | Purified | Inactivated | − | − |
| CP/97 (H7N2) (3) | s.c. | Purified | Inactivated | − | − |
| TW/68 (H5N9) | i.v. | AFe | Live | + | + |
| TW/68 (H5N9) | i.n. | AF | Live | + | + |
| RNC/93 (H7N2) | i.n. | AF | Live | + | + |
| Ck/NY/94 (H7N2) | i.n. | AF | Live | + | + |
| CP/97 (H7N2) | i.n. | AF | Live | + | + |
| DK/Ab/76, H1N1 | i.v. | AF | Live | + | + |
| CP/97 (H7N2) (1) | s.c. | Commercial | Inactivated | − | − |
| CP/97 (H7N2) (2) | s.c. | Commercial | inactivated | − | − |
| CP/97 (H7N2) (3) | s.c. | Commercial | inactivated | + | − |
WPR chickens were inoculated with AI virus A/Turkey/Wisconsin/68 (TW/68), A/Chicken/Pennsylvania/21342/97 (CP/97), A/Rhea/NorthCarolina/39482/93 (RNC/93), or A/Chicken/New York/13142-5/94 (CNY/94) for generation of immune sera. For one group, 4-week-old turkeys were infected with A/Duck/Alberta/35/76 (DK/Ab/76) virus.
Chickens were vaccinated one to three times s.c. For live virus infections, poultry were infected i.v. or i.n. Individual serum samples were collected from four to five birds after infection or vaccination and pooled.
ELISA plates were coated with the MBP-NS1 fusion protein, whose concentration was adjusted to 1 μg/ml in PBS. Sera from immunized poultry were diluted 1:100 or 1:200 before addition to ELISA plates. For the ELISA results with the 1:200 dilution OD values of all preimmune serum samples from the controls ranged from 0.096 to 0.133. Serum samples were considered positive for the NS1 protein if they yielded an OD greater than the mean plus 4 standard deviations for the control sera.
Values in parentheses indicate the number of vaccinations.
AF, allantoic fluid.