Moreover, the sphingosine precursor ceramide inhibits IAV infection in vitro [50], S1P receptor signaling protects mice from pathogenic influenza [51], while S1P lyase (SPL) enhances type I IFN production to restrict IAV replication [52,53], indicating that sphingolipid metabolism occupies an important place in influenza virus infection. This evidence concerns the gene SGPL1 and influenza.