Newborn Babies' Immune Systems Stronger Than You Think

It turns out that newborn babies, albeit fragile, have immune systems that are stronger than you think. New research shows that newborn immune T cells may have the ability to trigger an inflammatory response to bacteria, an important immune response.

Babies may have immune systems that function differently than those of adults, but they still have an immune system that apparently can still pack a punch, according to the study.

Our immune system includes two important types of immune cells: neutrophils and lymphocytes, which are then divided into B cells and T cells. Neutrophils play an important role in the frontline defense against infection, while B cells produce antibodies and T cells target cells infected with viruses and microbes.

Until now, it was generally believed that babies have an immature immune system that doesn't trigger the same inflammatory response normally seen in adults. Although babies, who are easily susceptible to germs, to need to protect themselves from harmful pathogens, it was thought that their T cells were suppressed to some extent to prevent inflammatory damage to the developing child.

However, researchers from King's College London set out to characterize the properties of T cells over a newborn's first few weeks of life. They did this by examining very small samples of blood in 28 highly premature babies.

The team found that while T cells in newborn babies are largely different than those in adults, it is not because they are immunosuppressed. Rather, they manufacture a potent anti-bacterial molecule known as IL8 that activates 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," lead author Dr. Deena Gibbons said in a statement. "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 findings were published in the journal Nature Medicine.