STAT1 and infection: Knockdown of TLR4 or SLAMF1 did not substantially alter HMPV-induced STAT1 phosphorylation at early time points, although SLAMF1 depletion significantly reduced STAT1 phosphorylation at 20 h post-infection (Figure 5E), consistent with the reduced HMPV-N mRNA and protein levels in these MDMs (Figures 5E, F).