TABLE 4.
Immunization of hamsters with rB/HPIV3-G1 and/or rB/HPIV3-F1 induces resistance to challenge with HPIV3 and RSV 28 days postinfection
| Immunizing virusa | No. of animals | Mean HPIV3 titerb (log10 TCID50/g ± SEd)
|
Mean RSV titerc (log10 PFU/g ± SEd)
|
||
|---|---|---|---|---|---|
| Nasal turbinates | Lungs | Nasal turbinates | Lungs | ||
| rB/HPIV3-G1 | 6 | 2.3 ± 0.1 (A) | 3.1 ± 0.2 (A) | 1.9 ± 0.2 (AB) | ≤1.7 (A) |
| rB/HPIV3-F1 | 6 | 2.6 ± 0.2 (A) | 3.1 ± 0.1 (A) | 2.9 ± 0.4 (BC) | 2.1 ± 0.2 (A) |
| rB/HPIV3-G1 and rB/HPIV3-F1 | 6 | 2.8 ± 0.2 (A) | 2.8 ± 0.3 (A) | 1.8 ± 0.1 (A) | 1.9 ± 0.4 (A) |
| rB/HPIV3 | 6 | 2.3 ± 0.5 (A) | 3.6 ± 0.4 (A) | 4.1 ± 0.5 (C) | 3.5 ± 0.4 (B) |
| RSV | 6 | 5.6 ± 0.2 (B) | 5.2 ± 0.2 (B) | 1.9 ± 0.3 (AB) | ≤1.7 (A) |
Groups of six hamsters were inoculated intranasally with 106 TCID50 of the indicated PIV3 or 106 PFU of RSV in a 0.1-ml inoculum. Nasal turbinates and lungs were harvested 5 days later for virus titration.
HPIV3 titrations were performed on LLC-MK2 cells. The limit of detectability of virus was 101.7 TCID50/g of tissue.
Quantitation of RSV was determined by plaque enumeration on HEp-2 cells. The limit of detectability of virus was 101.7 PFU/g of tissue.
Mean virus titers were assigned to similar groups (A, B, and C) by the Tukey-Kramer test. Within each column, mean titers with different letters are statistically different (P < 0.05). Titers indicated with two letters are not significantly different from those indicated with either letter.