TABLE 1.

Survival rates among immunized and control mice after infection with E. coli O157:H7

Group	No. of surviving mice/no. of dead mice on postchallenge day:				Survival rate (%)
	3	5	10	21
A2a	30/0	26/4	26/4	26e/4	86.6
B2b	30/0	28/2	28/2	28e/2	93.3
C2c	30/0	14/16	8/22	8/22	26.7
D2d	30/0	20/10	9/21	9/21	30.0

^aMice immunized with EHEC ghosts once (day 0).

^bMice immunized with EHEC ghosts twice (day 0 and day 28).

^cMice immunized with PBS once (control for group A2).

^dMice immunized with PBS twice (control for group B2).

^eP > 0.001.