TABLE 4.
Protective immunity against strain FSC033 elicited by i.d. immunization with LVS or FSC043a
| Immunizing strain (challenge route and dose in CFU) | Time to death (days)
|
|
|---|---|---|
| Individual | Median | |
| None (i.d., 10) | 5, 5, 6, 6, 6 | 6 |
| LVS (i.d., 1,000) | 5, >35, >35, >35, >35 | >35b |
| FSC043 (i.d., 1,000) | 11, 12, >35, >35, >35 | >35b,c |
| None (aerosol, ∼10) | 5, 5, 5, 5, 6 | 5 |
| LVS (aerosol, ∼10) | 6, 6, 11, 13, >35 | 11b |
| FSC043 (aerosol, ∼10) | 5, 7, >35, >35, >35 | >35b,c |
a
Mice immunized 77 days earlier by intradermal inoculation with 106 CFU of LVS or FSC043 and age-matched controls were challenged intradermally or by aerosol with various doses of virulent type A F. tularensis strain 33, and survival was monitored.
b
Significantly longer survival than controls (P < 0.05) by log-rank analysis of survival curves.
c
Not significantly different from mice immunized with the same dose of LVS (P > 0.05) by log-rank analysis of survival curves.