Babies have stronger immune defense mechanism than previously thought, according to a new study by King's College London.

the researchers said that although a newborn's immune system functions differently than that of adults, their immune T cells have the ability to activate an inflammatory response to bacteria.

Human's immune system comprises of several different types of immune cells. For example, neutrophils play an important role in the frontline defense against infection, lymphocytes B cells produce antibodies and lymphocytes T cells target cells infected with viruses and microbes.

Until now, it was believed that babies have an immature immune system that doesn't initiate inflammatory response normally observed in adults. It was also thought that their T cells were immunosuppressed that prevented inflammatory damage to the growing child.

In order to determine the properties of T cells, the researchers analysed blood samples of 28 premature babies in their first few weeks of life.

The researchers found that T cells in newborn babies are different to those in adults. They produce a strong anti-bacterial molecule called IL8 that has not been previously considered a product of T cells. IL8 has been found to trigger neutrophils to attack the body's foreign invaders.

"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," Dr Deena Gibbons, lead author in the Department of Immunobiology, said in a statement.

The researchers said that this T cell activity could be considered in future treatments to enhance the immune system of neonates in intensive care and to lower morbidity and mortality risk. Premature babies face heightened risk of developing inflammatory diseases like necrotising enterocolitis (NEC), where severe inflammation destroys tissues in the gut.

The finding is published in the journal Nature Medicine.