Picture a pandemic and you may think of smallpox, tuberculosis, cholera and the Black Death. Closer to home, the 2009 influenza pandemic is still fresh in people’s memories – and the H1N1 virus that caused it is still under study. Recently, scientists at St. Jude Children’s Research Hospital discovered that in the human viruses, the hemagglutinin protein responsible for fusing the virus to its target cell became more stable in an acidic environment than it was in earlier swine viruses (1) – exactly the property needed for airborne human-to-human transmission. They also demonstrated that when the protein was mutated to increase its activation pH, it lost the ability to spread via airborne particles. We spoke with Charles Russell, who led the project, to find out more.

References
- M Russier et al., “Molecular requirements for a pandemic influenza virus: an acid-stable hemagglutinin protein”, Proc Natl Acad Sci USA, [Epub ahead of print] (2016). PMID: 26811446.