There’s a nip in the air, and that can only mean one thing: it’s the beginning of cold and flu season, when it seems like everyone you know has developed a sudden case of the sniffles. It’s as though the first gust of winter weather brings with it all the nasty cold and flu viruses. Yet bacteria and viruses are always around, as seen by even a summer cold. Why then do more cases of the common cold, influenza, and now COVID-19 occur when the weather is chilly?
Researchers behind a new study have uncovered what they believe to be the biological cause of why more people acquire respiratory diseases in the winter. The nose’s immunological response to the chilly air is already compromised, it turns out. For the first time, we have a mechanistic explanation for why our innate immune response slows down in cooler temperatures.
This is the first biological or molecular explanation for why cooler temperatures seem to inhibit a certain aspect of our innate immune response. In a minor drop in temperature, your immune system is weakened to the point where you are more susceptible to viral infection. Bleier and his group, including collaborator and pharmaceutical sciences department head at Northeastern University in Boston Mansoor Amiji, set out on a scientific scavenger hunt to determine the cause of this phenomenon.
The nose is the primary entrance route for viruses and bacteria that cause respiratory illness. The researchers found that the front of the nose is the first to see the germ, long before the back of the nose is aware of the invader. Extracellular vesicles (EVs) are basic replicas of cells that are promptly produced by the cells lining the nose.
The study discovered that when the nose is under attack, extracellular vesicles are produced at a 160% higher rate. However, there were also key distinctions, such as the fact that the billions of extracellular vesicles in the nose had much more receptors on their membrane than the original cells, greatly increasing their capacity to halt the spread of viruses.
