TABLE 1.
Outcome of immunized mice after live intranasal F. tularensis Schu S4 challenge
| Immunization typea | Immunization routeb | Survival 14 days postchallenge |
Time to death postchallengec |
||
|---|---|---|---|---|---|
| No. of survivors/total no. (%) | Pd | Avg ± SD (days) | Pe | ||
| V (control) | i.p./i.p., i.p./i.n., i.n./i.p./i.n. | 0/34 (0) | 4.9 ± 0.3 | ||
| F. tularensis Schu S4-V | i.p. | 0/5 (0) | NS | 6.4 ± 0.9 | <0.01 |
| i.p./i.p. | 1/10 (10) | NS | 6.8 ± 1.0 | <0.001 | |
| i.p./i.n. | 7/35 (20) | 0.011 | 6.1 ± 0.9 | <0.001 | |
| i.n./i.p. | 2/8 (25) | 0.033 | 6.3 ± 1.0 | <0.01 | |
| i.n./i.p./i.n. | 2/9 (22) | 0.040 | 7.0 ± 0.8 | <0.001 | |
| i.n./i.n. | 0/11 (0) | NS | 5.5 ± 0.5 | NS | |
| i.n./i.n./i.n. | 3/15 (20) | 0.025 | 5.9 ± 0.8 | <0.001 | |
| s.c./i.p., s.c./i.n., s.c./s.c. | 0/30 (0) | NS | 5.7 ± 0.7 | <0.001 | |
a
Mice were immunized with control vesicles (V) or Schu S4-V at 2-week intervals by the indicated routes. Two weeks after the final immunization, all mice were challenged with ∼20 CFU (ranging from 3 to 49 CFU in different experiments) of F. tularensis Schu S4 by the intranasal route.
b
i.p., intraperitoneal; i.n., intranasal; s.c., subcutaneous.
c
Mean and standard deviation of time to death were calculated from only those animals that succumbed to infection.
d
Fisher's exact test, P value compared to that of control; NS, not significant.
e
One-way ANOVA, P value of Tukey posttest compared to that of control.