Special cells in the nose protect children from COVID-19 – scientists

The type of cells we have in our nose changes as we age and how that affects our ability to fight off COVID-19

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The milder course of COVID-19 in children can be explained by the fact that the body’s first line of defense – nasal cells – works better than in the elderly, who are prone to a severe course of the disease.

The scientists came to this conclusion based on the results of the study, published in Nature Microbiology, writes MedicalXpress.

The scientists focused on the early effects of SARS-CoV-2 infection on human nasal epithelial cells (NEC). Scientists took samples from healthy children (from 0 to 11 years old), adults (30-50 years old) and the elderly (over 70).

These cells were grown using special methods and received different cell types.

Using single-cell RNA sequencing, scientists identified 24 different types of epithelial cells.

Cell cultures from each age group were then either truly infected with SARS-CoV-2 or only mock-infected.

After 3 days, the epithelial cells of the nose reacted quickly in children: they increased the level of interferon (the first line of the body’s antiviral defense), which limits the spread of the virus. However, this antiviral response was weaker in older study participants.

The scientists also found that NEC in the elderly produced more infectious virus particles and had more cell damage.

“The study shows how the type of cells we have in our noses changes as we age and how this affects our ability to fight SARS.

CoV-2 infection may be crucial for the development of effective antiviral agents adapted to different age groups, especially for the elderly, who are at greater risk of severe COVID-19“, said the head of the project, associate professor of the Institute of Children’s Health, Claire Smith.

A strong antiviral response to nasal epithelial cells in children may explain why younger people usually experience milder symptoms. But the older a person gets, the higher the damage and the faster the virus replicates, which probably causes a more severe course of the disease.

The risk of death among infected people over 85 remains high, despite vaccination and improved treatment options.

“Amazingly, when we remove the immune cells from the nasal samples and leave only the nasal epithelial cells grown in a dish, we can still detect age-related differences in our body’s response to SARS-CoV-2 between the young and the elderly, explaining why children usually protected from severe form of COVID-19“, said the co-author of the study, Dr. Marko Nikolic.

Dr. Smith added that understanding cellular differences early in infection is just the beginning. Next, the scientists plan to investigate the long-term effects of these cellular changes and test therapeutic interventions.

The team suggests that future research should look at how aging affects the body’s response to other viral infections.