Table 5. Protective immunity in vaccinated BALB/c mice to re-infection with F. tularensis LVS.
Vaccine Strain | Immunization dose | Survival ratioa | Median time to death (days) |
---|---|---|---|
LVS ΔguaA | |||
Group 6 | 9.0 × 102 | 4/5 | >28 |
Group 8 | 9.0 × 104 | 5/5 | >28 |
Group 10 | 9.0 × 106 | 5/5 | >28 |
Group 11 | 9.0 × 107 | 4/4b | >28 |
LVS ΔguaB | |||
Group 12 | 1.05 × 102 | 0/5 | 5 |
Group 14 | 1.05 × 104 | 5/5 | >28 |
Group 16 | 1.05 × 106 | 5/5 | >28 |
Group 17 | 1.05 × 107 | 5/5 | >28 |
Gelatin 0.1%-PBS | |||
Group 18 | None | 0/5 | 5 |
Groups of BALB/c mice pre-vaccinated (see table 3) with 10 fold dilutions of LVSΔguaA (groups 6 to 11); LVSΔguaB (groups 12 to 17) and gelatin 0.1% - PBS (group 18) were injected with 2.5 × 103 CFU of parental LVS strain by intraperitoneal route.
Survival ratio, number of survival animal/ total number of animals immunized at day 28.
One mouse dead after the immunization with LVSΔguaA derivative strain