Children’s immune systems are better prepared to fight the coronavirus.
The immune system uses two special mechanisms to protect children from new viruses. In other words, children are protected from severe coronavirus infection in two ways. At an early age, the mucous membrane of the respiratory tract is very active. In children, the system responds more quickly to viruses it has never encountered (such as pandemics). At least, that’s what Irina Lehmann and her colleagues found in a recent study at the Berlin Institute for Health in Charité.
The researchers examined the differences in mucous membrane cells in children and adolescents. As the research team at Nature Biotechnology reports, children not only have more immune cells in their mucous membranes, but their bodies are able to produce type 1 interferon more quickly. Interferon type 1 plays a very important role in the fight against viruses. As a result, these key molecules can prevent the immune system from malfunctioning with the coronavirus.
“There are two ways to defend against a virus,” says Lehmann. First, the body receives an antiviral response in cells through receptors that, for example, produce interferon. “Immune cells in the tissue, such as active killer cells and neutrophils, then begin to function.” A study by his team shows that these two levels of viral control in children are on alert. They analyzed approximately 270,000 cells from nasal mucosal samples from people about one month to 77 years old. About half of them were infected with the SARS-CoV-2 virus, the virus that causes coronary heart disease.
These samples also showed that cells in children’s bodies produced higher amounts of immune receptors. This allows the virus to be detected faster and an immune response to be sent faster. One of these MDA5 receptor molecules is a sensor for foreign RNA found in many viruses, including SARS-CoV-2. It also produces type I interferons, which are involved in boosting the immune system’s ability to respond quickly to viruses. Interferons activate immune cells and put them in a certain state of consciousness. This makes it difficult for viruses to multiply.
“Interferons are very effective against viral infections,” says Marco Binder, co-author of the Nature Biotechnology study at the Heidelberg Cancer Research Center in Germany. However, as an effective control measure, the new coronavirus has its own proteins that block the production of interferon. “The SARS-CoV-2 virus multiplies very quickly in cells, which means that virus proteins are formed very quickly,” said Binder, who studies interferons. “They suppress the interferon system so dramatically that if there is an infection, we see minimal production of interferon in cell culture or no production at all.”
The dual role of interferon
In lung epithelial cell culture, Binder tested whether more MDA5s might maintain the interferon response, as seen in children. Adults have very few of these receptors – molecules must be produced from the beginning if they become infected. This process is time consuming and the SARS-CoV-2 virus can thus suffocate the entire immune system. They seem to be safe because of the stronger MDA5 base and similar receptors. In fact, Binder’s experiments showed that in children, SARS-CoV-2 was slow in blocking the production of interferons.
Therefore, children are almost doubly protected against viruses of the SARS-CoV-2 family. Type 1 interferons not only warn the body against viruses, but are also responsible for regulating the signals of a number of processes in the immune response. In the absence of interferons during infection with the SARS-CoV-2 virus, the body’s immune system is at its weakest. The spread of the virus causes tissue damage, which puts the body’s immune system under more pressure to fight off the virus.
However, in the absence of type 1 interferons, the defense response is dangerously imbalanced. As a result, the immune response causes extensive tissue damage in the lungs. Other results of the study again indicate the important role of interferons. Interferons prevent people with congenital malformations from developing serious illnesses caused by the presence of the corona virus.
Children can still be severely infected with the corona virus
As described, the pediatric immune system responds rapidly to the presence of the SARS-CoV-2 virus by rapidly producing interferon and preventing it from spreading throughout the body. “Conversely, if the concentration of MDA5 in the body increases, the body goes through the first stage of fighting the virus, which is protein production,” explains Binder. “That’s why cells produce a lot of interferon quickly after contact with the virus – even before the SARS-CoV-2 virus is allowed to multiply.”
If the child’s interferon system is disrupted, for example due to a genetic defect, this protective effect is lost. “This explains why some seemingly healthy children and young people get the Corona virus,” says Binder. “But the important thing is that in general, children can fight the virus much faster and more effectively than adults.”
This effect also continues in the second stage of the immune system’s response because essential immune cells, such as killer cells, are actively present in the body and ready to defend against the virus. One of the main findings of Lehmann et al.’s study is that children have more of these killer cells in their conical membranes than adults. “A number of cells that are responsible for protecting the body are present in the body’s tissues and do their job automatically,” he says. These cells do not need to be called by different signals. “Of course, if the production of the virus in the body increases, the situation will be different.”
Adult immune system against coronavirus
Studies show that children’s immune systems are designed to fight the virus effectively. Experts such as Peter Palese, an independent researcher at the Icahn School of Medicine in Mount Sinai, New York, who has been studying independently, believe that children’s immune systems can behave better than adults’ in an epidemic – a problem that has a definite effect. It was observed in the early 1918s, following the outbreak of other epidemics. But adults have to rely on their adapted immune systems to deal with the disease. An adapted immune system is able to fight pathogens by producing antibodies and T cells.
This proves that there is a major defect in new epidemics. Unlike seasonal respiratory pathogens, which are usually identifiable and treatable in childhood, viruses such as coronavirus make people, especially adults, defenseless by making changes in the body. To prove this point, we can look at coronary heart disease statistics, which show that older people are more at risk.
But why do only children have this effective protection? Binder explains that there are several reasons. “If the body always activates this process, the immune system will launch a severe attack on the virus,” he says. “But in addition to the viruses learning to adapt, the body is unable to keep the system active in the long run.” “Of all the immune messenger systems, the interferon response causes the most changes in the cell’s genetic activity,” Binder said. If this response is activated permanently in the body, it will have many effects on cells, their activity and consequently the body.
This is not just a theoretical problem. “We know that people who congenitally produce more interferon in their bodies suffer from very serious inflammatory diseases,” says Binder. Therefore, the amount of its production needs to be controlled by the body. “Otherwise, the SARS-CoV-2 virus can break down the protective wall and destroy the entire immune system.” However, in the first years of life, we seem to be one step ahead of the virus.