Fig. 5.

Survival results of guinea pigs vaccinated with PA alone (▪) or PA+spore antigens (▴) and challenged i.d. (a) or i.n. (b) with Ames spores. All vaccines were given as three immunizations each separated by 4 weeks and all contained ~30 µg PA or 30 µg PA+10 µg BclA+10 µg ExsF+10 µg p5303 and ~500 µg AL. The control groups (•) received PBS and AL alone. The guinea pigs challenged by i.d. injection (a) received ~156 spores delivered in 200 µl WFI and the guinea pigs challenged through i.n. instillations (b) received ~1.35×10⁷ spores delivered in 100 µl WFI. The guinea pigs challenged i.d. were significantly protected with PA alone (P = 0.0062 for percentage survival and 0.0002 for the survival curve) and the vaccine including spore antigens was also protective (P<0.0001 for percentage survival and 0.0002 for the survival curve). The P value comparing the survival curves of PA alone with PA+spore antigens was 0.067. When challenged i.n., the animals receiving PA alone were significantly protected (P = 0.013 for TTD and P = 0.0002 for the survival curve), as were the animals receiving the PA vaccine with the addition of the spore antigens (P = 0.012 for TTD and P = 0.0002 for the survival curve). There were 10 animals per group with the exception of the negative-control groups, which contained nine animals in each group.