Figure 1.

Immunogenicity and protective efficacy of CP5 and CP8 conjugate vaccines in BALB/c mice. Groups of four BALB/c mice were immunized on days 0, 14, and 28 with 10, 2, or 0.4 µg of CP5-CRM, CP8-CRM, or CRM alone adsorbed to 100 µg aluminum phosphate adjuvant. Blood was collected from each mouse before each immunization and prior to challenge. Serum was diluted 1:100 for evaluation of antibodies to CP5 or CP8 by ELISA (A). On Day 42, the mice were challenged intraperitoneally with ∼10⁷ CFU of (C) Reynolds (CP5) or (D) Reynolds (CP8). Quantitative blood cultures were performed on heparinized blood collected by tail vein puncture 2 h after challenge. Data are presented as means ± standard errors and were analyzed by one-way ANOVA with multiple comparisons made to the group receiving CRM alone. ****, P < 0.0001; *, P < 0.05. For each experiment, the results of one representative experiment are presented; each was repeated at least twice.