A study by researchers at the University of Michigan Health System is helping settle parents’ concern about why their babies get sick so often. People have been under the assumption that children will develop the ability to fight viral infections when they get older, just like walking and talking. However, this new research shows that the natural ability to fight infection is there early on.
According to researchers, this study, published in Nature Immunology, shows that signals from key cells inhibit the growth of essential immune cells early in life. In order to improve an infant’s response to infection, the scientists suggest blocking that signal.
Yasmina Laouar, Ph.D., study senior author and assistant professor in the University of Michigan Department of Microbiology and Immunology, said:
“What happens at early age is that natural killer cells, like many other immune cells, do not complete their functional maturation until adulthood. During this time, we are left with an immature immune system that cannot protect us against infections, the reason why newborns and infants are more prone to infection.”
Infant immunity has never been fully understood. Scientists have not been able to explain why the natural killer cell responses are deficient. In this study, the experts demonstrate the role of a cell (transforming growth factor beta- TGF-β) that can help us understand why.
TGF-β is a protein that controls cellular differentiation, proliferation, and other important functions in most cells. Other than immunity, it also plays a role in heart disease, cancer, diabetes, AIDS, Parkins Disease, and more.
Results showed TGF-β, produced in the bone marrow, is responsible for the production of natural killer cells. In infant mice, natural killer cells matured faster in the absence of TGF-β signaling.
If TGF-β signaling was blocked, the mice had 10 times more mature natural killer cells when they reached adulthood.
“Our overall goal was to determine the factors that constraint the production and maturation of natural killer cells early in life. To our surprise, we discovered that natural killer cells can complete maturation as early as 10 days of age is TGF-β signaling is blocked.”
The authors believe this finding could be used to propose the functional inactivation TGF-β signaling as a strategy to reverse the deficit of natural killer cells early in life, but additional research will be needed.
Written by Sarah Glynn