One of the first challenges any newborn faces is the risk of infection. But researchers from the University of Utah recently discovered a special peptide in babies’ umbilical cord blood that may help prevent life-threatening inflammation and sepsis, as they reported in the Journal of Clinical Investigation [PDF]. Called the neonatal NET inhibitory factor (nNIF), this amino acid chain keeps the body from producing NETs (neutrophil extracellular traps), fibers whose job is to capture pathogens. This slows the inflammatory response, making the immune system less effective. The researchers believe harnessing this process could help treat inflammation and sepsis—and not just in babies.

It may seem counterintuitive that having a slower immune system would be considered advantageous, but the researchers theorize nNIF may actually be very important to a newborn baby. "The immune system has to be dampened during those first few days and weeks of life because the baby is being exposed to all these new proteins it's never seen before," Christian Yost, lead author on the study and an associate professor of pediatrics at Utah State University, tells mental_floss. If the baby's immune system responded in a robust way, it would kill not only dangerous germs, but the good bacteria colonizing the baby's body for the first time. It may serve a purpose before the baby is born too. "We think this represents one of the mechanisms of tolerance that keep the baby's immune system from attacking the mother," he says.

This peptide only exists in the cords and circulatory systems of newborn babies for about two weeks; then it disappears. While the NET fibers it produces help the immune system fight off invading bacteria and viruses, Yost says they're "two edges of a sword. You've got to have enough NET formation to limit the spread of infection. If you have too much, or it happens in a place where it's not supposed to, that can be equally as injurious."

To test the power of nNIF, seven families with premature babies agreed to let Yost and his colleagues extract blood from their babies' cords and take blood samples from their bodies. After synthesizing the nNIF peptides from the samples in a laboratory, Yost’s team delivered them in a series of tests to mice with different types of infections. They injected, for example, lipopolysaccharides into the abdomens of mice to mimic a gram negative infection like pneumonia, which Yost says stimulates a "robust inflammatory response." They also injected E. coli bacteria—a big cause of sepsis in people young and old—into the peritoneal space of the mice. In the last model of infection, part of the mice's large intestines were tied off and small punctures made so that bacteria leaked into the peritoneal cavity and caused "a model of polymicrobial sepsis." In every case, Yost says, "mice that were treated [with the nNIF peptides] had 30 to 40 percent increased survival, compared to the ones that were not treated."

Obtaining cord blood from babies may be a sensitive issue for some, but many new parents either donate the cords to research or have them preserved in a cord bank. Moreover, Yost reassures that such cells could be replicated in the lab. "Now that we know the sequence for the NET-inhibitory peptides, we do not need to harvest them from umbilical cord blood to use them for experiments or, in the future, as a potential therapeutic agents."

Yost believes these inhibitory peptides can make a huge dent in preventing intense inflammation—which can be very painful—and potentially lethal infections from sepsis in premature babies, and have potential as a treatment that could benefit people of any age.