Induction of sIL-6R, IL-32 and IL-6 expression by IAV infection. (a) sIL-6R, IL-32 and IL-6 mRNA levels were quantitated by real-time RT-PCR in A549 cells infected with IAV (MOI=1) or control-treated (heat-inactivated IAV) for 6 h or 24 h. (b) sIL-6R, IL-32 and IL-6 mRNA levels were quantitated by real-time RT-PCR in human PBMCs infected with IAV (MOI=1) or control-treated (heat-inactivated IAV) for 2 h or 6 h. (c) sIL-6R, IL-32, and IL-6 mRNA levels were quantitated by real-time RT-PCR in MRC-5 cells infected with IAV (MOI=1) or control-treated (heat-inactivated IAV) for 2 h or 6 h. Data shown are mean±s.e.; n=3. **P<0.01; *P<0.05. IAV, influenza A virus; MOI, multiplicity of infection; PBMC, peripheral blood mononuclear cell; sIL-6R, soluble interleukin-6 receptor.