HPSE and infection: These are other genes reported to exhibit antiviral capacities during hMPV infections: heparanase (HPSE), which cleaves heparan sulfate and could reduce the binding of the G protein to the target cell [80,81]; CD9, a surface protein expressed by epithelial cells and B cells, implied in tyrosine kinase signal transduction [80,82]; and P2RY6, a pyrimidinergic receptor responsive to UDP, UTP, and ADP, which mediates inflammatory responses, possibly via the sensing of pyrimidine nucleotides released into the extracellular fluid after cell lysis [80].