FIG 7.

(A) Mice were immunized at days 0 and 14 with 10 μg each of pRBD-NQ constructs, and anti-RBD IgG levels were measured in the serum and stool 10 days after the final immunization by ELISA. (B) Mice were challenged 4 months following the last immunization with C. difficile strain VPI 10463, and relative weight loss (left) and survival (right) are shown. (C) Mice were immunized with pRBD-NQ at days 0, 14, 28, and 403 with 10 μg each of pRBD-NQ constructs, and anti-RBD IgG levels were measured in the serum after the final immunization. Experiments were performed with 7 to 10 mice/group, and circles represent means ± standard errors of the means from one experiment. (D) Mice were challenged 4 months later with C. difficile strain UK1, and relative weight loss (left) and survival (right) are shown. Statistical differences were determined using a log rank test. P values of ≤0.05 were considered to be significant.