Fig. 2

Active viral replication induced MUC15 upregulation but MUC15 did not interfere with viral replication a: Plaque assay showed viral replication in hNECs with or without H3N2 infection or UV-inactivated H3N2 (UV) (n = 2). b: Quantitative real-time RT-PCR analysis of MUC15 mRNA expression in hNECs treated with or without H3N2, UV-inactivated H3N2 (UV) or 25 μg/mL poly (I:C) for 24 and 48 h with uninfected control subjects as baseline (n = 2), using PGK1 as the internal control. Relative mRNA expression levels were calculated using 2^ ^(−ΔΔCt) method; the fold change was compared against uninfected control subjects. c: Western blot analysis of MUC15 protein expression on hNECs treated with or without H3N2, UV-inactivated H3N2 (UV) or 25 μg/mL poly (I:C). Cells were harvested at various times as indicated (n = 2). d: Viral replication in hNECs transfected with non-targeting siRNA (NT-siRNA) or MUC15-siRNA and normal hNECs (n = 1). e-f: Viral replication in MDCK cells (E, n = 3) and hNECs (F, n = 1) treated with 0, 2 or 30 ng recombinant MUC15 protein (rMUC15) before or after H3N2 infection. g: Immunoprecipitation with MUC15 protein followed by Western blotting for hemagglutinin (HA), matrix protein 1 (M1), neuraminidase (NA) and MUC15 (n = 2). Median values with 25th and 75th percentiles are indicated by error bar. * denotes P value of less than 0.05 compared with uninfected control. Uni: uninfected control; Unt: untreated control