Table 2.
Influence of the Route of Administration on pXL2 Immunogenicity and Protective Ability
| Immunogen | Route | Mean anti-RSV F ELISA titer |
IgG1/IgG2a | Mean plaque reduction titer | Mean virus lung titer* | No. fully protected mice‡/ No. immunized mice | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| IgG | IgG1 | IgG2a | ||||||||||||||||
| Log2 titer/100 + SD | Log2± SD | Log10 PFU/g ± SD | ||||||||||||||||
| A | pXL2 | i.m. | 7.63 ± 0.92 | 4.25 ± 1.91 | 4.00 ± 1.71 | 1.06 | 10.49 ± 0.76 | 0.00 ± 0.00 | 9/9 | |||||||||
| pXL2 | i.d. | 7.35 ± 1.00 | 5.00 ± 1.00 | 0.50 ± 1.27 | 10.00 | 8.60 ± 2.00 | 0.43 ± 1.13 | 8/9 | ||||||||||
| pXL0 | i.m. | 0.50 ± 0.51 | 0.00 ± 0.00 | 0.00 ± 0.00 | 0.36 ± 0.50 | 4.30 ± 0.22 | 0/9 | |||||||||||
| B | RSV | i.n. | 9.00 ± 0.67 | 5.00 ± 0.82 | 6.90 ± 0.57 | 0.73 | 12.88 ± 0.34 | 0.00 ± 0.00 | 9/9 | |||||||||
| FI-RSV | i.m. | 7.10 ± 0.99 | 4.60 ± 0.97 | 0.00 ± 0.00 | infinite | 9.20 ± 1.10 | 0.00 ± 0.00 | 9/9 | ||||||||||
Mice were immunized with pXL2 (100 μg), pXL0 (100 μg), RSV (106 PFU), or FI-RSV (100 μl) at 0 and 6 wk. Immune sera were analyzed at wk 9, 1 wk before the RSV challenge (106 PFU, i.n.). Lung RSV titers were determined 4 d after challenge.
*
Detection sensitivity: 101.69 PFU/g lung.
‡
“Fully protected mice” refers to animals with no detectable RSV in lungs after RSV challenge.