Scientists from the United States have identified a protein that contributes to greater infection with coronavirus in the elderly 
Researchers from the United States have shown that chitinase 3-like protein 1 ( CHI3L1), the content of which in the body increases with age, contributes to the infection of coronavirus infection. This, according to scientists, whose article was published in JCI Insight, may be the reason why the elderly and patients with underlying medical conditions are more susceptible to COVID-19.
CHI3L1 is used in a signaling pathway that is activated during inflammation. At the same time, it has been found that blood levels increase not only during infections associated with inflammation – emphysema, asthma or COPD – but also as a person ages. They can best predict death in people over 80 years old.
Scientists from Brown and Yale Universities decided to identify the relationship between CHI3L1 and the ACE2 receptor, with which the coronavirus binds when it enters the cell. In the course of experiments, they analyzed the effect of the protein on ACE2 and other proteases that contribute to the development of infection in both mice and cell cultures.
As a result, it turned out that CHI3L1 levels increased both with age and with the presence of concomitant diseases and infections. In addition, the protein acted as an ACE2 stimulator. At the same time, the researchers developed a humanized monoclonal antibody FRG that attacks a specific region of CHI3L1, which successfully blocked the induction (increase in the amount and activity) of the receptor. “Thus, the virus cannot enter the host cells. This means that with the use of FRG antibodies, the prevalence of infection will be less, ”explains one of the researchers, Zuhitra Kamle.