Expression of M gene segment of influenza A virus determines host range

The host range of the influenza A virus (IAV) is restricted by dysregulated expression of the M viral gene segment, according to a study published August 15 in the open-access journal PLOS Pathogens by Anice Lowen and John Steel of Emory University School of Medicine, and colleagues. IAV pandemics arise when a virus adapted to a non-human host overcomes species barriers to successfully infect humans and sustain human-to-human transmission. To gauge the adaptive potential and therefore pandemic risk posed by a particular IAV, it is critical to understand the mechanisms underlying viral adaptation to human hosts. To address this question, Lowen and Steel examined the role of one of IAV’s eight gene segments, the M segment, in host adaptation. The authors compared the growth of IAVs with avian- and human-derived M segments in avian and mammalian systems. The avian, but not the human, M segment restricted viral growth and transmission specifically in mammalian cells....