EV71 inhibits type I interferon responses upstream of IRF3 activation.

<p>(<b>A</b>) HeLa cells were infected with EV71 (multiplicity of infection [MOI] = 10) and SEV (20 HA/mL) for the indicated time. Supernatants were collected, and type I IFN production was measured by the type I IFN bioassay in the 2FTGH-ISRE cell line. Results were expressed as mean ± SD among triplicate samples. (<b>B</b>) HeLa cells were infected with SEV (20 HA/mL, lanes 1–5) and EV71 (MOI = 10, lanes 6–10) for indicated time. Cell lysates were subjected to native PAGE, and the presence of IRF3 monomers and dimers was detected by western blot. (<b>C</b>) HeLa cells were mock- or EV71-infected (MOI = 10) at the indicated time before SEV infection (lanes 3&4), and then the cells were super-infected with SEV (20 HA/mL) for 24 h (lanes 2–4); cells infected with SEV alone served as a positive control for IRF3 dimerization (lane 2). Cell extracts were subjected to IRF3 dimerization assay by native PAGE (upper panel). The same samples were resolved by SDS-PAGE followed by western blot analysis using a polyclonal antibody against Sendai virus (middle panel) and an antibody against actin (lower panel).