Table 2.
DNA immunization with a vector encoding RSV M2 protein lacking the immunodominant CTL epitope induces significant but reduced protection compared to immunization with the wild-type M2 genea
| Material used for immunization | Virus titer in the indicated tissue(log10 PFU/g tissue) | |
|---|---|---|
| Lung | Nasal turbinates | |
| PBS | 5.3 ± 0.1 | 4.8 ± 0.1 |
| pcDNA3.1 (empty vector) | 5.2 ± 0.04 b | 4.7 ± 0.09 b |
| M2-wt DNA vaccine | 3.2 ± 0.4 c | 3.4 ± 0.3 d |
| M2-Y83R_I90T DNA vaccine | 4.6 ± 0.1 c | 3.7 ± 0.4 d |
a
BALB/c mice (n=5) were immunized with one of the immunogens at day 0, 14 and 21, and challenged with live RSV on day 28 (day 7 after the third immunization, the expected peak day of CTL activity). Lung titers were determined on day 4 following challenge (the expected peak day of viral replication).
b
No significant difference from values obtained for mice immunized with PBS. (P≥0.05)
c
Significantly different from values obtained for mice immunized with PBS (P<0.01).
d
Significantly different from values obtained for mice immunized with PBS (P<0.02).