Fig. 3: Virus titers and cytokine and chemokine gene expression detected in the supernatant of infected alveolar epithelial cells.

A Alveolar epithelial cells (AECs) were infected with the A/Hong Kong/415742/2009 (415742pdm), A/Hong Kong/483/1997 (483/H5N1), A/Duck/Hong Kong/Y280/97 H9N2 (Y280), or A/bat/Egypt/381-OP/2017 H9N2 (381) viruses at an MOI of 0.01 and maintained in culture at 37 °C. Viral titers in culture supernatants collected at 1, 24, and 48 h post inoculation (hpi) were determined by TCID₅₀ assays in MDCK cells. Bar charts show the data as the mean +/− SD (n = 6 individual donors). B Viral titers from panel A are depicted as AUCs. Bar charts show the data as the mean + SD (n = 6 individual donors). The horizontal line denotes the limit of detection of the TCID₅₀ assay. C AECs were infected with the indicated viruses at an MOI of 2 and maintained in culture at 37 °C. Expression of the mRNA of viral M genes and of the mRNAs encoding cytokines (IFN-β and IFN-λ1) and chemokines (IP-10; regulated on activation, normal T cell–expressed and secreted [RANTES]; and MCP-1) in AECs at 24 hpi is shown. Bar charts show the data as the mean + SD of the results for five individual donors. Statistical analysis was performed using two-way ANOVA with Tukey’s post-test (A) or one-way ANOVA followed by Tukey’s post-test (B, C); P < 0.05 was considered to indicate statistical significance, and exact P values are presented. Source data are provided as a Source data file.