TABLE 7.

Protective immunity against strain FSC033 elicited by i.d. immunization with LVS or defined mutants of SCHU S4a

Immunizing strain (dose in CFU)Challenge route and dose in CFUTime to death (days)
IndividualMedian
Nonei.d., 104, 4, 5, 5, 55
LVS (106)i.d., 500>35, >35, >35, >35, >35>35b,c
ΔFTT0918 (105)i.d., 500>35, >35, >35, >35, >35>35b,c,d
ΔiglC mutant (106)i.d., 5004, 7, 7, 7, 87b
NoneAerosol, ∼104, 5, 5, 5, 55
LVS (107)Aerosol, ∼105, 7, 7, 77
ΔFTT0918 (105)Aerosol, ∼109, 11, 11, 19, >35, >3515b,c
ΔiglC mutant (107)Aerosol, ∼105, 5, 6, 6, 66
  • a Mice (4 to 6/group) were immunized by intradermal inoculation with the indicated strain and together with age-matched control mice challenged intradermally 8 weeks later with ∼500 CFU of type A strain FSC033 or by aerosol 9 weeks later with ∼10 CFU of FSC033, and survival was monitored.

  • b Survived significantly longer (P < 0.05) than control mice (rank-sum test).

  • c Survived significantly longer (P < 0.05) than mice immunized with the ΔiglC mutant.

  • d Group survival not different from that of LVS-immunized mice.

  • e Survived significantly longer (P < 0.05) than all other aerosol-challenged test groups.