It was long believed that a newborn's immune system was an immature version of an adult's, but new research from Cornell University shows that newborns' T cells – white blood cells that protect from disease – outperform those of adults at fighting off numerous infections.
But during the COVID-19 pandemic, many were surprised by the apparent lack of illness in infants, bringing this long-standing belief into question. This new study explains why.
Adult T cells outperform newborn T cells at tasks including recognizing antigens, forming immunological memory and responding to repeat infections, which has led to the belief that infant's T cells were just a weaker version of the adult ones.
Cornell team Brian Rudd, associate professor of microbiology and immunology, and Andrew Grimson, professor of molecular biology and genetics had now discovered that newborn T cells are not deficient: Instead, they are involved in a part of the immune system that does not require antigen recognition: the innate arm of the immune system. While adults T cells use adaptive immunity – recognizing specific germs to then fight them later – newborn T cells are activated by proteins associated with innate immunity, the part of the immune system that offers rapid but nonspecific protection against microbes the body has never encountered.
This enables newborn T cells to do something that most adult T cells cannot: respond during the very first stages of an infection and defend against a wide variety of unknown bacteria, parasites and viruses.
"We know that neonatal T cells don't protect as well as adult T cells against repeat infections with the same pathogen. But neonatal T cells actually have an enhanced ability to protect the host against early stages of an initial infection," Rudd said. "So, it is not possible to say adult T cells are better than neonatal T cells or neonatal T cells are better than adult T cells. They just have different functions."
But during the COVID-19 pandemic, many were surprised by the apparent lack of illness in infants, bringing this long-standing belief into question. This new study explains why.
Adult T cells outperform newborn T cells at tasks including recognizing antigens, forming immunological memory and responding to repeat infections, which has led to the belief that infant's T cells were just a weaker version of the adult ones.
Cornell team Brian Rudd, associate professor of microbiology and immunology, and Andrew Grimson, professor of molecular biology and genetics had now discovered that newborn T cells are not deficient: Instead, they are involved in a part of the immune system that does not require antigen recognition: the innate arm of the immune system. While adults T cells use adaptive immunity – recognizing specific germs to then fight them later – newborn T cells are activated by proteins associated with innate immunity, the part of the immune system that offers rapid but nonspecific protection against microbes the body has never encountered.
This enables newborn T cells to do something that most adult T cells cannot: respond during the very first stages of an infection and defend against a wide variety of unknown bacteria, parasites and viruses.
"We know that neonatal T cells don't protect as well as adult T cells against repeat infections with the same pathogen. But neonatal T cells actually have an enhanced ability to protect the host against early stages of an initial infection," Rudd said. "So, it is not possible to say adult T cells are better than neonatal T cells or neonatal T cells are better than adult T cells. They just have different functions."
