Small children constantly sniff and bring home every infection. Nevertheless, their immune system is by no means weaker than that of adults, according to researchers in the journal Science Immunology after experiments with young mice and human cells.
In particular, the D cells of the immune system act quickly and efficiently when in contact with previously unknown viruses. This may explain – among other factors – the mild course of corona infection in children.
Donna Farber, director of research at Columbia University Medical Irving Center in New York, says the baby’s immune system has a reputation for being weak and underdeveloped. But that is not true, babies and children are often infected with viral respiratory infections, for example the RSV virus (respiratory syncytial virus).
“Everything they encounter is new to children”
This is because children are the first to encounter these viruses. “Adults don’t get sick often because they have memories of these viruses that protect us,” says Farber. “For the kids, everything they encounter is new.”
In order to closely examine the capabilities of a child’s immune system, the researchers collected immune system T cells from young and adult mice. These include cells that have not previously been associated with a pathogen, called innocent T cells.
T cells are specialized defense cells. There are different types of these, for example some virus-infected cells identify and kill them, while others store the memories of individual pathogens to quickly initiate protective measures in the event of a renewed infection. The researchers donated the D cells to mice, which were later infected with the H5N1 virus.
Strong immune system
Innocent T cells in young mice react to a much smaller virus than in adults. They multiply rapidly and migrate in large numbers to the lungs, where influenza viruses predominate.
The researchers were surprised to learn that cells function differently with age. “It’s a baby’s immune system that is strong and efficient and can eliminate germs at an early age,” says Farber. “In some ways it may be better than an adult’s immune system because it is designed to respond to a wide variety of new pathogens.”
“Early childhood is the time when a large number of T cells are formed in the thymus,” explains Marcus Peters, chairman of the Pulmonary Immunology Committee at the University of Rohr in Pocham. “As we age, fewer and fewer T cells are formed, which means our ability to react to new things decreases.”
Children perform better in the corona than adults
Adults also have a reservoir of innocent T cells, but small. For this purpose, the elderly have a fixed reservoir of memory T cells that have developed during their lifetime, which are designed for the immune response to certain pathogens. If they come in contact with known pathogens, their immune system can act quickly.
The child’s ability to quickly find the answer to new dangers may be beneficial in the case of SARS-Cowie-2. The virus is new to everyone, so you are currently experiencing a direct comparison between the immune system of a child and an adult. “And kids do better.” Older adults who respond to a new virus will respond more slowly. This gives the virus more time to multiply and you will get sick.
Antigens in immunosuppressive vaccines always activate only T cells that are compatible with them. For example, T cells that respond to the corona virus do not respond to pneumococci. Immunologist Peters says vaccines do not put too much pressure on the immune system. In general, the immune system is constantly active and constantly manipulates antigens that enter the body from the environment, becoming harmless and causing disease. (SDA)