Covid-19: Why don't some people get sick? The answer in a protein

Covid-19: Why don't some people get sick? The answer in a protein


There are those who count one or two infections. And who, on the other hand, can say that they have never yet fallen ill with Covid-19. Perhaps for greater attention in wearing the mask or, more generally, in respecting the anti-contagion measures? Not only that: the lungs would also play a role, or rather a protein inside them capable of blocking the virus. The study, carried out by researchers at the University of Sydney and recently published in Plos Biology, could finally reveal the key to immunity to the coronavirus.

How the study was carried out

Not it is the first time, in fact, that the scientific community has wondered why some people have never fallen ill with Covid-19, while others can present even very serious forms of the disease. In the new study, the researchers used the genetic engineering tool Crispr, which enabled them to turn on all genes in the human genome, to search for proteins with the ability to bind to Sars-Cov-2. From the analyses, they discovered a receptor protein, which is found in the lungs and which attaches to the coronavirus, or rather to the spike protein, like a sort of Velcro. In doing so, therefore, it manages to immobilize it and move it away from the target cells.

Crispr, “allowed us to find this new receptor protein, Lrrc15 ” , commented Greg Neely, one of the authors of the study. “We analyzed the lungs of patients who died from Covid or other diseases and found that those with severe Covid had tons of this protein in their lungs ” . Despite the production of Lrrc15, the researchers point out, these patients probably died because this protein was produced in insufficient quantities or too late to actually help. “We have not been able to examine the lungs of patients who survived Covid as a lung biopsy is not something easy to perform on living people”, continues the expert. "We expect, however, that there are even higher amounts of this protein in survivors than in deceased."

The possible implications

Another recent study by the Imperial College of London, which examined blood samples for Lrrc15 and found that the protein was lower in patients with severe Covid than in patients with a mild form of the disease. “The fact that there is this natural immune receptor that we didn't know about, that lines our lungs and blocks and controls the virus, is crazy,” Neely comments.

Also from the investigations, the team found that Lrrc15 it is also expressed in fibroblasts, the cells that control pulmonary fibrosis, a disease that is one of the possible complications of Covid-19. A discovery, therefore, that could have important implications for the treatment of long Covid. “We can now use this new receptor to design broad-acting drugs capable of blocking viral infection or even pulmonary fibrosis, for which we currently do not have good treatments” , concludes the expert.