Substitution of CpG for alum promotes induction of Th1 cells, which enhances the efficacy of a laboratory-prepared pertussis vaccine.

<p>Mice were immunized i.p. twice (0 and 28 days) with PBS, laboratory-prepared Pa in PBS (Ag) or formulated with alum (Al) or CpG. Mice were challenged by exposure to an aerosol of live <i>B. pertussis</i> 14 days after the second immunization. (A) The number of CFU in the lungs were quantified at intervals after challenge. (B) <i>B. pertussis</i>-specific cytokine production by spleen cells on day of challenge. (C) <i>B. pertussis</i>-specific antibody in serum on the day of challenge. +p<0.05, ++p<0.01, +++p<0.001 CpG versus alum; *p<0.05, **p<0.01, ***p<0.001 versus antigen in PBS. (D) WT, IL-17A^−/− or IFN-γ^−/− mice were immunized i.p. twice with a laboratory-prepared Pa formulated with CpG. Mice were challenged by exposure to an aerosol of live <i>B. pertussis</i> 14 days after the second immunization. The number of CFU in the lungs were quantified at intervals after challenge. Results are mean values for 4 mice per group at each time point and each panel (except D) is representative of 2 independent experiments.