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. 2015 Jun 29;212(12):1939–1948. doi: 10.1093/infdis/jiv341

Figure 5.

Figure 5.

Survival of immunized mice after secondary pneumococcal pneumonia challenge and bacterial densities in mice. Mice were mock-immunized with medium or immunized with the PR8/PB2–green fluorescent protein (GFP) or PR8/PB2–pneumococcal surface protein A (PspA) virus 3 times at 2-week intervals. Two weeks after the final vaccination, mice were intranasally challenged with 1.0 × 103 plaque-forming units (PFUs) of A/New Caledonia/20/99 (NC) virus. Ten days after the viral challenge, mice were intranasally challenged with 6.0 × 103 colony-forming units (CFUs) (sublethal dose; A, B) or 2.0 × 107 CFUs (3-fold 50% mouse lethal dose; C, D). A, C, Survival was monitored in 10 mice for 10 days after the bacterial challenge. *P < .05; †P < .01. B, D, Lung tissues were harvested 5 days after bacterial challenge and subjected to bacterial titration on sheep blood agar. The detection limit of Streptococcus pneumoniae is 10 CFUs/mL. Values represent mean (standard deviation) log10 CFUs per lung for 6 mice per group. *P < .05; †P < .01. Abbreviation: NS, not statistically significant.