Infants are susceptible to respiratory illnesses, as any parent knows.
Even though most people believe that the adult immune system is better at fighting off new viruses, a recent research suggests that the immune system of a child is actually stronger than previously thought.
There’s a common misconception that babies’ immune systems lack the strength and maturity of an adult’s, but according to Columbia University Vagelos College of Physicians and Surgeons’ Donna Farber PhD, professor of microbiology & immunology and the George H. Humphreys II Professor of Surgery, this isn’t entirely accurate.
A specific mechanism in the immune system protects infants against new viruses. Compared to adults, their airway mucous membranes are substantially more active. In youngsters, this system responds more quickly to viruses it has never seen, such as pandemic infections.
When compared to adults, infants are more susceptible to respiratory disorders caused by viruses including influenza and respiratory syncytial virus. Virus exposure in newborns, on the other hand, is a very recent phenomenon. “Adults don’t get ill as frequently because we’ve stored memories of these infections that protect us, but everything the newborn experiences is novel to them,” Farber adds.
As a result of this new research, Farber and his colleagues eliminated the influence of immunological memory by solely testing the immune system’s capacity to react to novel pathogens.
The researchers took naive T cells (immune cells that have never been exposed to a disease) from both newborn and adult mice for the head-to-head comparison. An adult mouse had been infected with a virus when the cells were injected into it.
The baby T cells were victorious in the fight against the virus because they were able to detect lower amounts of the virus than adult T cells, and they were able to multiply more quickly and migrate more quickly to the site of infection, forming a powerful defence against the virus. Human newborn T cells were shown to have comparable advantages over adult T cells in a laboratory study.
In this study, we were looking at naive T cells that had never been activated, so it was a surprise that they responded differently based on age,” Farber said. “This means that the infant’s immune system is strong, efficient, and able to eliminate germs early in life. It may be even better than the adult immune system since it’s geared to respond to a wide variety of novel diseases.”
The COVID case looks to be an example of this. A comparison of the adult and newborn immune systems is now possible since SARS-CoV-2 is novel to everyone, adds Farber. “In addition, the children are doing lot better than they were before. In the face of an unfamiliar disease, adults are slower to react. As a result, the virus has a better chance of spreading, which is why you begin to feel ill.”
Vaccines are more effective in children because their T cells are more strong, according to the study. As Farber puts it: “That is the time to acquire immunizations; don’t be concerned if you get many shots in that window.” “In the pre-mask era, every infant was exposed to a massive number of new antigens on a daily basis. Multiple exposures are already being handled by them.”
It is possible that this research will lead to improved vaccines for children.
It is possible, argues Farber, to use smaller doses of vaccinations in children because of the unique immune responses that children have. This might lead to vaccines that are more effective for children of this age, he adds.
Infant T cells are developmentally adapted for robust lung immune responses through enhanced T cell receptor signaling– Rebecca S. Guyer, Donna L. Farber. Science Immunology, 2021; 6 (66) DOI: https://www.science.org/doi/10.1126/sciimmunol.abj0789