We then used the wild type or mutated IAV to infect SERINC5-expressing A549 cell line, and observed that SERINC5 reduced the infection of wild type IAV and IAV mutant with N87 HA, but exerted no inhibition for HA mutants 127, 155 and 160 (Fig 5G and 5H). This evidence concerns the gene SERINC5 and infection.