Scientists from the University of Sydney discovered that there is a special protein in people’s lungs that neutralizes the SARS-CoV-2 virus, preventing it from entering the cell. This discovery may explain why some people do not contract the coronavirus, while others suffer from a severe form. Research published in the journal PLOS Biology.
For a coronavirus to enter a cell, the spike protein must bind to the ACE2 receptor. In particular, most of these receptors are in the lungs, so signs of infection mainly affect the respiratory system.
The authors of a new study showed that many molecules of another receptor, LRRC15, are found in the lungs of people who have died from the coronavirus. It can also bind to the spike protein of the coronavirus. But LRRC15 does not support infection: on the contrary, the virus “sticks” to it and becomes unable to infect cells.
LRRC15 begins to be produced after the immune system encounters the coronavirus particles. Researchers believe that while patients who have died from Covid-19 may have high levels of LRRC15, it is not enough to protect or is produced too late to help. They suggest that survivors have more of this protein, but this can only be confirmed using a lung biopsy, an invasive procedure.
The scientists noted that their colleagues at Imperial College London had independently found that the absence of LRRC15 in the blood was associated with more severe COVID, supporting their hypothesis.
LRRC15 is also produced in fibroblast cells that control the development of pulmonary fibrosis, a disease that causes damage and scarring of lung tissue. The scientists’ discovery will help develop tools for the prevention and treatment of COVID, as well as a cure for pulmonary fibrosis.