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)
IndividualMedian
None (i.d., 10)5, 5, 6, 6, 66
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, 65
LVS (aerosol, ∼10)6, 6, 11, 13, >3511b
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.