Replicating viruses work together to thwart opponents
19 Feb 2023
New research into the cooperative and competitive behaviour of viruses in the human body could help shed light on methods for tackling pandemic events.
A study of the influenza A virus reveals factors that determine how viruses spread successfully from one human cell to another and the circumstances in which they might fail.
While viruses are equipped to invade cells and hijack their usual functions in order to replicate, they face the problem of defending their control of the cell’s resources against others of the same type also seeking hosts.
Some occupants are able to create barriers to entry but are vulnerable to invaders while building their defences. Their solution is revealed by scientists at the MRC-University of Glasgow Centre for Virus Research (CVR) in their research paper ‘Superinfection exclusion creates spatially distinct influenza virus populations’, published in PLOS Biology.
It reveals that viruses would divide a host cell into microscopic territories for replication, then aid one another by entering neighbouring cells together, in order to further spread and to secure the new cell hosts against competition.
Study leader Anna Sims explained the team used viruses engineered to produce fluorescent proteins in one of two different colours but had been employing these for a different experiment.
“This study came from seeing something unexpected down the microscope and looking to find out more. We had previously been using fluorescent viruses in a very standard experiment, but when we looked, we could also see signs that they were fighting,” explained Sims.
“The idea that viruses can establish territories in their hosts is incredible to see because, in biology, we observe the establishment and defence of territories in many areas, from ants, to trees, to cancer. We now believe that viruses are doing exactly the same thing in humans, but at a microscopic level.”
Senior author Dr Ed Hutchinson said the finding would “probably” apply to a variety of viruses that can spread within hosts.
“In the case of influenza, we know that new pandemic strains of influenza appear when different influenza viruses get into a host separately, replicate, and then come together to make a new virus as they spread within their host’s airway,” remarked Hutchinson.
“The work done in this study shows that it is a lot harder than we had thought for influenza viruses to pull this off. This knowledge can now be used to find out what factors help pandemic viruses to overcome these barriers.”
Pic: Two influenza A viruses, one labelled magenta and one labelled green, have spread rapidly across this sheet of cells, but are unable to cross into each other’s territory. Photo by Anna Sims, MRC-University of Glasgow Centre for Virus Research
