With the threat of hundreds of thousands – possibly millions – of people being infected and healthcare systems becoming overwhelmed, the race is on to develop a vaccine that will protect individuals and slow the spread of the disease. But Professor Jonathan Heeney, one of the people working on a vaccine, says that coronaviruses present a particular challenge to vaccine developers.
Coronaviruses are named after their appearance: they are spherical objects, on the surface of which sit ‘spike’ proteins. The virus uses these spikes to attach to and invade cells in our body. Once inside, the virus uses the cell’s own machinery to help itself replicate and spread throughout the body, causing disease and allowing it to transmit onwards.
Traditionally, scientists would develop vaccines that programme the body to produce antibodies that recognise and block these spikes. But this strategy can misfire with coronaviruses due to a phenomenon known as ‘antibody-induced enhancement’ or ‘vaccine-induced enhancement’, says Heeney.
“If you make antibodies against the spike, they can end up binding to it and helping the virus invade important immune cells known as monocyte-macrophages. Rather than destroying the virus, these cells can then end up being reprogrammed by the viruses, exacerbating the immune response and making the disease much, much worse than it would otherwise be.”
Image: Coronavirus
Credit: TheDigitalArtist
Reproduced courtesy of the University of Cambridge