Scientists from the Fred Hutchinson Cancer Research Center announced on Monday that they have found a new mechanism that strains of influenza can use to infect cells.
Influenza viruses have two main ways they can infect cells - one with a protein called hemagglutinin that allows the virus to infect a cell. Another protein that usually allows the virus to escape cells, neuraminidase, was found to be used to infect cells as well.
"We expected that viruses with the mutated hemagglutinin wouldn't be able to infect cells," Jesse Bloom, an evolutionary biologist and assistant member of the Fred Hutch Basic Sciences Division, said. "So we were surprised when a virus with this hemagglutinin started to grow. We were even more surprised when we sequenced the virus and discovered that it had evolved a mutation in neuraminidase."
The researchers looked at the mutation that allowed the virus to use neuraminidase to attach to host cells. They found that what was thought to be the most crucial and singularly important way for influenza to attach to and infect cells, was not needed when neuraminidase was used.
"This was not a mutation we expected to find in the lab, let alone in viruses that have infected humans over the past few years," Kathryn Hooper, a graduate research assistant in the Bloom Lab, said. "It suggests there is influenza circulating in nature that may be infecting cells by a mechanism that has been overlooked by others in the field."