‘Trojan Horse’ of immune system revealed
28 Aug 2015 by Evoluted New Media
Human cells use viruses as a ‘Trojan Horse’ to transport a messenger that encourages the immune system to fight the viral infection.
A research team at Oxford University studied the detection of a virus after it enters a cell in the body by a protein known as cGAS. They discovered that as part of this mechanism, as some viruses replicate within the cell they incorporate cGAMP – a signalling molecule that activates the immune system – which can prompt an immune response.
“We hypothesised that as the virus replicated; cGAMP was incorporated and carried to the next cell to be infected. This may not have been spotted before because in the lab researchers tend to use cells that are free of cGAS and therefore unable to produce cGAMP,” said Professor Jan Rehwinkel from Oxford University’s Radcliffe Department of Medicine.
In the study, published in Science Express, the team added high levels of cGAS to some cells and compared the processes to that which occurred in cells lacking the protein.
“By putting cGAS back into some of these cells, we were able to compare what happened as the virus moved to infect new cells. Viruses from cells that had been loaded with cGAS and could produce cGAMP stimulated a much more potent immune response when they moved into new cells than viruses that had come from cells without cGAS,” said Professor Rehwinkel.
The team confirmed their findings by using cells from mice with naturally occurring levels of the protein. They compared these to cells from genetically engineered mice that were cGAS free and found that where cGAMP was produced, it travelled within the virus particles.
Next, the team will study how their findings could be used to improve viral vectored vaccines, treatments which use genetically engineered virus particles to prompt an immune system response. They will investigate whether loading these particles with cGAMP molecules would trigger a bigger immune response, making such vaccines more effective.
Paper: http://www.sciencemag.org/content/early/2015/07/29/science.aab3632.abstract
