TABLE 5 .

Protective efficacy of RASV strains expressing fimbriae in a constitutive manner (Saf⁺, Sti⁺, Stc⁺, and Agf⁺) and producing PspA antigen^a

Strain	Constitutively expressed fimbrial gene	No. of mice alive/total no. (% survival)
		Expt 1	Expt 2	Combinedb
χ11595(pYA4088)	sti	4/8 (50)c	2/11 (18.2)	6/19 (31.6)c
χ11850(pYA4088)	saf	5/8 (62.5)d	5/11 (45.5)	10/19 (52.6)e
χ11851(pYA4088)	stc	5/8 (62.5)d	5/11 (45.5)	10/19 (52.6)d
χ12038(pYA4088)	agf	3/8 (37.5)	2/11 (18.2)	5/19 (26.3)
χ11606(pYA4088) (Δ4)		1/8 (12.5)	1/11 (9.1)	2/19 (10.5)
χ9088(pYA4088)		NTf	3/11 (27.3)	3/11 (27.3)
None (PBS) (control)		0/8 (0)	0/11 (0)	0/18 (0)

^aSeven-week-old BALB/c mice were immunized orally with ~1 × 10⁸ CFU of the indicated of S. Typhimurium vaccine strains and boosted with the same dose 6 weeks later. All mice were challenged by intraperitoneal inoculation 4 weeks after the booster dose with ~1 × 10⁴ CFU of virulent S. pneumoniae strain WU2. Deaths were recorded until 3 weeks postinfection.

^bCombined percent survival from two independent experiments.

^cSignificantly different (P < 0.05) from value obtained for the control (PBS) group.

^dSignificantly different (P < 0.01) from value obtained for the control (PBS) group.

^eSignificantly different (P < 0.001) rom value obtained for the control (PBS) group.

^fNT, not tested.