FIG. 4.

Pneumovax 23 (PVAX) elicits a protective antibody response in Cxcl13^−/− mice. Wild-type and Cxcl13^−/− mice were immunized intraperitoneally with 10 μg of Pneumovax 23. Blood samples were obtained on 0, 7, and 14 days postimmunization and Pneumovax 23 (A)- or PPS3 (B)-specific IgM levels were determined by ELISA. Data points represent individual animals, and horizontal bars represent means of results for each group. The statistical significance of genotypes was measured by two-way ANOVA, with significance reached at a P of <0.05. (C) Four weeks following Pneumovax 23 immunization, mice were challenged with 5,000 CFU of S. pneumoniae WU2 (serotype 3) and survival was monitored for 10 days. The differences between the results for the two genotypes were not statistically significant.