Study Finds Infant Immune Systems Stronger Than Commonly Perceived

A new study shows that the infant immune system is stronger than most people think and can outdo adults in fighting off new pathogens, according to a Columbia University press release.

The immune systems of infants have a reputation for being weak and underdeveloped compared to the adult immune system; however, Donna Farber, PhD, professor of microbiology & immunology and the George H. Humphreys II Professor of Surgical Sciences at Columbia University Vagelos College of Physicians and Surgeons, said that unlike adults, babies are seeing viruses such as influenza for the first time.

“Adults don’t get sick as often because we’ve recorded memories of these viruses, and the memories protect us, whereas everything the baby encounters is new to them,” Farber said in the press release.

The new study only tested the immune system’s ability to respond to a new pathogen, essentially eliminating any contribution from immunological memories. The researchers collected naïve T cells, defined as immune cells that have never encountered a pathogen, from both infant and adult mice and placed the cells into adult mice infected with a virus.

In the experiment, the naïve T cells from infant mice detected lower levels of the virus than adult cells and the infant cells proliferated faster and traveled in greater numbers to the site of the infection, rapidly building a strong defense against the virus. Further, a laboratory comparison found similar enhancements among human infant T cells compared to adults, according to the study authors.

“We were looking at naïve T cells that have never been activated, so it was a surprise that they behaved differently based on age,” Farber said in the press release. “What this is saying is that the infant’s immune system is robust, it's efficient, and it can get rid of pathogens in early life. In some ways, it may be even better than the adult immune system, since it’s designed to respond to a multitude of new pathogens.”

The new findings also help explain why vaccines are particularly effective in childhood, when T cells are very robust, according to Farber.

“That is the time to get vaccines and you shouldn't worry about getting multiple vaccines in that window,” Farber said in the press release. “Any child living in the world, particularly before we started wearing masks, is exposed to a huge number of new antigens every day. They’re already handling multiple exposures.”

According to Farber, the study could lead to better vaccine designs for children.

“Most vaccine formulations and doses are the same for all ages, but understanding the distinct immune responses in childhood suggests we can use lower doses for children and could help us design vaccines that are more effective for this age group,” Farber said in the press release.

REFERENCE

Infant immune systems are stronger than you think. Columbia University Irving Medical Center. December 10, 2021. Accessed December 15, 2021. https://www.cuimc.columbia.edu/news/infant-immune-systems-are-stronger-you-think