Cold weather and various respiratory illnesses frequently coexist. This is because more people stay inside during winter, and viral survival is high in a low-humidity environment. However, it is less clear if and how low temperatures weaken human immunity.
A new study shows how the body fights viral invaders in the nose
A recent study published in the Journal of Allergy and Clinical Immunology describes a previously undiscovered mechanism by which the immune system combats viral invaders within the nose—and shows that it functions well in warm environments.
Pharmaceutical professor at Northeastern University Mansoor Amiji, the co-study author, said that the findings could create a way to potentially treat the common cold and assorted viruses. Amiji and colleagues had previously studied this and established that nasal cells release “extracellular vesicles,” which are tiny sacs sprayed that swarm and destroyed bacteria after inhalation. He explained that the best analogy would be a hornet’s nest, where bees protect the nest from attack. In a similar way EVs swarm, attach to and kill bacteria.
EVs target viral infections inside the nose
For the current research, the researchers sought to answer two questions. The first was whether EVs are released in the nose during viral infections. There other was, I f they are, are they linked to temperature?
To get answers to the first question, they employed a test substance replicating viral infection to stimulate nasal mucosa taken from volunteers with surgically removed polyps. Findings indicate that it did produce EVs targeting viral infections,
They divided nasal cell samples into two for the second question and cultured them in the laboratory. One group was subjected to 375 degrees Celsius and another to 32C. Researchers choose temperatures based on tests that established that temperatures inside the nose fall by around 5C if outside air drops between 23C and 4C.
During normal body heat conditions, EVs could fight off viral infections by presenting them with a decoy of targets they latch on rather than receptors that could otherwise target cells.
