Newborns' Immune System is Stronger Than Previously Thought

A new study on infants' immune system revealed that the immune T cells are much stronger than previously thought.

A human immune system consists of several types of immune cells that include neutrophils that play a key role in frontline defense against infections, the B cells that generate antibodies and the T cells that target cells infected with viruses and microbes.

Till date, it was widely accepted that babies have an immature immune system that fails to trigger the similar inflammatory responses as seen in adults. Although babies require the response to protect themselves from harmful pathogens they are being exposed to right from birth, it was believed that their T-cells were suppressed due to which they failed to prevent the inflammatory damage.

But the latest study led by researchers at King's College London, challenge these findings as they found that the immune T cells of the newborn have the ability to trigger an inflammatory response to bacteria. Their immune system functions very differently from adults, but they display a strong immune defense.

In this study, the researchers characterized the properties of T cells by examining samples of blood retrieved from 28 highly premature babies, as they developed over the first few weeks of life.

The researchers noticed that the T cells in infants vary largely from those of the adults, and this is not because they are immune-suppressed; but because they produce a potent anti-bacterial molecule called IL8. This molecule was not considered as a major product of T cells, till date and that it triggers neutrophils to attack the body's foreign invaders.

Dr Deena Gibbons, lead author in the Department of Immunobiology at King's College London, says: "We found that babies have an in-built anti-bacterial defense mechanism that works differently to adults, but nevertheless may be effective in protecting them. This may also be a mechanism by which the baby protects itself in the womb from infections of the mother. The next stage of our work will be to better understand the pathways that result in the immune cells of newborns being so different to those in adults."

The researcher suggests that in future, treatments aimed at boosting immune system in neonates can be possible by focusing on the T cells activity. Preemies face an increased risk of developing inflammatory diseases like necrotizing enterocolities, the common gastrointestinal surgical emergency in preemies that is responsible for 15 to 30 percent of infant mortality in the UK.

The finding is documented in Nature Medicine.