Table 2. Anti-spore antibody responses: titre comparisons of vaccinated and unvaccinated groups.

Statistical analysis of variance with post-hoc Tukey’s tests for pairwise group comparisons. Titres of sera collected from vaccinated mice in a representative experiment were determined by ELISA in plates coated with wild-type (WT) Ames or ΔbclA spores.

Week	Group compared with PBS controls*	Highest significant dilution†
		WT Ames plate	ΔbclA Ames plate
4	PA alone	<50‡	<50‡
	PA+BclA+ExsF combined (3)	3200	3200
	PA (1), BclA+ExsF separately (2)	<50‡	<50‡
8	PA alone	<50‡	<50‡
	PA+BclA+ExsF combined (3)	3 200	≥204 800
	PA (1), BclA+ExsF separately (2)	200	800
12	PA alone	<50‡	<50‡
	PA+BclA+ExsF combined (3)	≥204 800§	≥204 800
	PA (1), BclA+ExsF separately (2)	3200	51 200

^*The number of total vaccine doses over the course of the entire study is shown in parentheses. Vaccinations were administered on day 0, week 4 and week 8. All vaccinations included AL. For example, the third group in each set of three received one PA dose (25 mg) on day 0 and one PA+spore antigen dose (25 µg) on week 4 and a second on week 8.

^†Highest dilution with A₄₀₅ significantly elevated (P<0.05) compared with the PBS control (reciprocal dilution).

^‡P>0.05 at lowest dilution tested (1 : 50).

^§P<0.05 at highest dilution tested (1 : 204 800).