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. Author manuscript; available in PMC: 2009 Jul 27.
Published in final edited form as: J Infect Dis. 2005 Jun 8;192(2):249–257. doi: 10.1086/430954

Figure 4.

Figure 4

Lethal pneumococcal pneumonia in mice after infection with pairs of recombinant influenza viruses differing ∼ 2-fold in NA specific activity. Mice were challenged intranasally with 100 cfu of D39 lux pneumococcus 7 days after intranasal influenza infection. (A) Detection of pneumococcal pneumonia with a live imaging system in mice infected with HK/Sing/PR8 or HK/Syd/PR8 (9 mice/group). Pneumonia was defined as over 20,000 relative light units from the thorax. (B) Survival curves of the mice infected with HK/Sing/PR8 or HK/Syd/PR8 (19 mice/group). (C) Detection of pneumococcal pneumonia in mice infected with Fuj/Mem/PR8 or Fuj/Fuj/PR8 (9 mice/group). (D) Survival curves of the mice infected with Fuj/Mem/PR8 or Fuj/Fuj/PR8 (9 mice/group). (E) Daily live imaging of two representative mice. The mouse infected with HK/Sing/PR8 died of pneumonia on day 6 after pneumococcal challenge. The mouse infected with HK/Syd/PR8 survived through the experiment without pneumonia. Scale for the relative light units is shown on the right. One mouse infected with HK/Syd/PR8 and one with Fuj/Fuj/PR8 recovered from pneumonia; all the other mice that developed pneumonia died. An asterisk (*) indicates a significant difference in development of pneumonia or survival between the groups (P<0.05 by the Mantel-Cox χ2 test on Kaplan-Meier data).