Figure 5

Virus titer detected in the supernatant of influenza virus infected type I-like alveolar epithelial cells. Virus titer of the (A) A/HK/54/98 (H1N1) and (B) A/HK/483/97 (H5N1) was determined after apical infection and basolateral infection of the type I-like alveolar epithelial cells at 3 h and 24 h post infection. Aa = apical release after apical infection, Ab = basolateral release after apical infection, Ba = apical release after basolateral infection, Bb = basolateral release after basolateral infection. (C) At 24 h post infection following basolateral infection of type I-like alveolar epithelial cells, the titers of influenza H5N1 virus at the apical aspect of the cells is significantly more seen with H1N1 infected cells. Single and double asterisk indicates statistically significant difference with p < 0.05 and p < 0.01, respectively. Dotted line represents the lowest detection limit of the TCID₅₀ assay.