TASS, December 6th. Biologists have found that the increase in cases of acute respiratory viral infections during the onset of cold weather is due to the fact that low ambient temperature slows down the production of microbubbles with antiviral molecules in the cells of the nose. This was announced on Tuesday by the press service of the Massachusetts Eye Hospital (MEE).
“Traditionally it is believed that flu and cold epidemics occur during the cold season due to the fact that people spend more time indoors at this time, where viruses easily spread through the air. We have revealed the biological reasons for the existence of these seasonal variations in the frequency of development of various forms of SARS, including coronavirus infection,” said Benjamin Blayer, Associate Professor at Harvard University (USA), quoted by the MEE press service.
Blair and colleagues uncovered one of the main reasons for the increase in SARS during the onset of cold weather in a series of studies aimed at studying the innate immune system of the nose. A few years ago, scientists discovered that the cells of the nose are able to recognize infections and produce a large number of microbubbles filled with various antimicrobial molecules in response to the appearance of bacteria.
Subsequent experiments showed that these bubbles spread throughout the entire thickness of the mucous membrane of the nose and upper respiratory tract, where they interact with microbes and slow down their spread throughout the body. Having discovered this system of innate immunity, American molecular biologists became interested in whether it is involved in counteracting seasonal SARS.
With this idea in mind, the scientists collected nasal tissue samples from dozens of healthy volunteers and patients undergoing various surgical procedures in Boston hospitals, and monitored the response of these bodies to particles from three different viruses – two of the rhinoviruses that cause the common cold, as well as a form of SARS. -CoV-2.
Blayer and colleagues’ observations showed that nasal cells begin to produce microbubbles immediately after the first contact with all three respiratory pathogens. These structures contain fragments of various protein molecules that bind to viral particles and prevent them from entering real cells.
To do this, the scientists determined how the temperature inside a person’s nose changes during cold weather and used this information to correspondingly lower the temperature in the nutrient medium where the tissue samples they collected were stored.
Subsequent observations showed that a decrease in temperature of only five degrees Celsius led to the fact that the number of microbubbles produced by the cells of the nose decreased by about 42%, and the concentration of antiviral proteins in them fell noticeably. This, according to scientists, explains well why cold weather significantly increases the incidence of SARS.