Staphylococcus aureus Lipase 1 Enhances Influenza A Virus Replication.

Influenza A virus (IAV) causes annual epidemics of respiratory disease in humans, often complicated by secondary coinfection with bacterial pathogens such as Here, we report that the secreted protein lipase 1 enhances IAV replication in primary cells, including human lung fibroblasts. The proviral activity of lipase 1 is dependent on its enzymatic function, acts late in the viral life cycle, and results in increased infectivity through positive modulation of virus budding. Furthermore, the proviral effect of lipase 1 on IAV is exhibited during infection of embryonated hen's eggs and, importantly, increases the yield of a vaccine strain of IAV by approximately 5-fold. Thus, we have identified the first protein to enhance IAV replication, suggesting a potential role in coinfection. Importantly, this activity may be harnessed to address global shortages of influenza vaccines. Influenza A virus (IAV) causes annual epidemics and sporadic pandemics of respiratory disease. Secondary bacterial coinfection by organisms such as is the most common complication of primary IAV infection and is associated with high levels of morbidity and mortality. Here, we report the first identified factor (lipase 1) that enhances IAV replication during infection via positive modulation of virus budding. The effect is observed in embryonated hen's eggs and greatly enhances the yield of a vaccine strain, a finding that could be applied to address global shortages of influenza vaccines.