IMMUNE SYSTEM OF NEW BORN BABIES STRONGER THAN PREVIOUSLY THOUGHT

Contrary to what was previously thought, newborn immune T cells may have the ability to trigger an inflammatory response to bacteria, according to a new study led by King's College London. Although their immune system works very differently to that of adults, babies may still be able to mount a strong immune defense, finds the study published in the journal Nature Medicine.

Our immune system is made up of several different types of immune cells, including neutrophils which play an important role in the frontline defense against infection, and lymphocytes: B cells which produce antibodies, and T cells that target cells infected with viruses and microbes.

Up to 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 need to protect themselves from the harmful pathogens they are exposed to from birth, it was thought that their T cells were suppressed to some extent to prevent inflammatory damage to the developing child. Sceptical of this notion, the King's-led study set out to characterize the properties of T cells, examining very small samples of blood in twenty-eight highly premature babies, as they developed over the first few weeks of life.

The team discovered that whilst T cells in newborn babies are largely different to those in adults, it is not because they are immunosuppressed; rather, they manufacture a potent anti-bacterial molecule known as IL8 that has not previously been considered a major product of T cells, and that activates neutrophils to attack the body's foreign invaders.

Dr Deena GibbonsDeena 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."

This T cell activity could become a target for future treatments aimed at boosting the immune system of neonates in intensive care, where infection is a major risk for morbidity and mortality. Premature babies are also at serious risk of developing inflammatory diseases such as necrotising enterocolitis (NEC), where severe inflammation destroys tissues in the gut. NEC is the most common gastrointestinal surgical emergency in preterm babies, with mortality rates of around 15 to 30 per cent in the UK.

BABIES REMEMBER NOTHING BUT A GOOD TIME

Parents who spend their time playing with and talking to their five-month-old baby may wonder whether their child remembers any of it a day later

Thanks to a new BYU study, we now know that they at least remember the good times.

The study, published in Infant Behavior and Development, shows that babies are more likely to remember something if there is a positive emotion, or affect, that accompanies it.

"People study memory in infants, they study discrimination in emotional affect, but we are the first ones to study how these emotions influence memory," said BYU psychology professor Ross Flom, lead author of the study.

Although the five-month-olds can't talk, there are a number of different ways that researchers can analyze how the babies respond to testing treatments. In this particular study, they monitored the infants' eye movements and how long they look at a test image.

The babies were set in front of a flat paneled monitor in a closed off partition and then exposed to a person on screen speaking to them with either a happy, neutral or angry voice. Immediately following the emotional exposure, they were shown a geometric shape.

To test their memory, the researchers did follow-up tests 5 minutes later and again one day later. In the follow-up test, babies were shown two side-by-side geometric shapes: a brand new one, and the original one from the study.

The researchers then were able to record how many times the baby looked from one image to the next and how long they spent looking at each image. Babies' memories didn't improve if the shape had been paired with a negative voice, but they performed significantly better at remembering shapes attached to positive voices.

"We think what happens is that the positive affect heightens the babies' attentional system and arousal," Flom said. "By heightening those systems, we heighten their ability to process and perhaps remember this geometric pattern."

This paper was co-authored with Professor Brock Kirwan as well undergraduate and masters students Rebecca B. Janis and Darren J. Garcia. It follows a string of Flom's significant research on infants' ability to understand each others' moods, the moods of dogs, monkeys, and classical music.