A blood test to track the immune response to Covid-19
Adrian Hayday's team at the Crick and King's College London are working with Guy's and St Thomas' NHS Trust to study blood from Covid-19 patients, finding unexpected clues to explain why the disease can be life-threatening in older people and mild or even asymptomatic in others.
In a preprint shared in May 2020, the team described two prominent clues that could be used to identify the patients most likely to require additional treatment - an overt dysregulation in a specific type of T cell that ordinarily eradicates virus-infected cells, and a dramatic loss of immune cells called basophils that can be involved in tissue repair.
The evolution of the SARS-CoV-2 spike protein
Researchers in Steve Gamblin’s lab at the Crick used cryo-electron microscopy to characterise the structure of the SARS-CoV-2 spike protein, as well as its most similar relative – the spike protein on a bat coronavirus.
The June 2020 Nature and Structural Biology paper found that although the spikes themselves are 97% similar, there are a number of significant differences at the location where SARS-CoV-2 binds with a receptor on human cells, called ACE2, and at the surfaces that keep the subunits of the spike together. These differences mean the spike of SARS-CoV-2 is more stable and is able to bind around 1,000 times more tightly to a human cell than this bat virus.
Visualising neurons and blood vessels in the eye in 3D
An international team led by Crick group leader Katie Bentley published the results of a seven-year project to develop a new way to produce three-dimensional images of neurons and blood vessels in a mouse eye. The researchers used light sheet fluorescence microscopy (LSFM) to quickly take images of live and static mouse retina.
They used the technique to examine blood vessels in mice with a condition called oxygen-induced retinopathy. By examining the abnormal blood vessels in 3D, they saw that the shapes and structures were very different from what they had expected to see based on other descriptions. The team are already working on a follow-up study to confirm how these abnormal blood vessels form and grow.
Pre-existing coronavirus antibodies
Researchers from the Crick and UCL analysed hundreds of blood samples taken before the pandemic and found that a small fraction had antibodies that reacted with SARS-CoV-2. These cross-reactive antibodies were found more frequently in children aged 6 to 16.
It’s thought that these antibodies were produced when people were infected with common cold-causing coronaviruses in the past. The team believe that this could help to explain why children are less likely to become severely ill with COVID-19. However, there’s no evidence yet that the antibodies prevent SARS-CoV-2 infection or spread.
Gut bacteria and muscle contraction in the colon
A team from Vassilis Pachnis’s and Gitta Stockinger’s groups at the Crick, and Bern University, discovered how gut bacteria can regulate the function of the nerves that control the muscles of the colon.
The researchers found that gut bacteria are necessary to activate a specific gene in nerve cells, which in turn signals to the muscles to push the colon contents along. This work helps us understand how the gut and nerve cells communicate to control intestinal function.
It could also explain why people on antibiotics, which reduce the amount of bacteria in the gut, can suffer from intestinal problems.