MoDCs phenotype expression induced by successive challenge of influenza virus and pneumococcus. (A) MoDCs were infected with H1N1 at MOI 0.1 or treated with heat killed pneumococcus at 1 × 106, 5 × 106 or 10 × 106 CFU. Cell phenotypic maturation was examined at 24 hr, 30 hr or 48 hr after virus infection, or at 24 hr after pneumococcal stimulation. (B-D) MoDCs were concurrently or successively challenged by both influenza virus and heat killed pneumococcus. MoDCs were first infected with H1N1 at MOI 0.1 for 0 hr, and then immediately treated with 5 × 106 CFU heat killed pneumococcus for another 24 hr. The total incubation time at harvest was 24 hr. Alternatively, MoDCs were first infected with H1N1 at MOI 0.1 for 6 hr or 24 hr, and then treated with 5 × 106 CFU heat killed pneumococcus for another 24 hr to make up a total incubation time at harvest of 30 hr or 48 hr respectively. Data (n = 5-7) represented mean ± SD of six individual experiments. Please note that some groups of data were presented twice in different panels for easy interpretation. *p < 0.05, **p < 0.01, ***p < 0.001 (ANOVA) and ###p < 0.001 (Post test for trend).