In Brisbane, Australia, scientists have uncovered how a protein found in breast milk shields babies from dangerous lung infections — and the discovery could one day make baby formula even better at protecting infants.
The protein is called osteopontin, and researchers at QIMR Berghofer Medical Research Institute have spent years figuring out exactly how it works. Their study, published in the journal Cell, reveals that osteopontin triggers a chain of biological signals that help build up a baby's immune system in the liver and lungs during those critical first weeks of life.
Professor Simon Phipps, who leads the Respiratory Immunology Lab at QIMR Berghofer, said the difference was striking when his team removed osteopontin from their experiments. "We looked at the infant lung cells that line the airways when the osteopontin was missing. It was like night and day," he said. The protein influenced the community of helpful bacteria living in the baby's gut, which then produced substances that acted like hormones and activated growth factors that strengthened the immune system.
Human breast milk contains high levels of osteopontin, especially in the first weeks after birth. Some baby formulas already include osteopontin sourced from cow's milk, but not at the same amounts found in human milk. The new research could guide improvements to formula products in the future.
The team made a second surprising finding. They discovered that rosiglitazone, a drug already used to treat type 2 diabetes in adults, can mimic the protective effects of osteopontin by activating the same immune-supporting pathway in the body. In their laboratory tests, rosiglitazone helped protect infant lungs from respiratory infections, though this has only been shown in preclinical models so far and not in human babies.
Respiratory infections like pneumonia remain a leading cause of illness and death in young children worldwide, making any insight into prevention valuable.
Phipps noted that because osteopontin boosted immune-regulating pathways, it might also help prevent allergic conditions like eczema and asthma — though researchers said this would need to be tested formally in future studies.
"Our study adds to the growing scientific understanding of the complex bioactive components in human milk and how they influence infant development during these critical windows in early life," Phipps said.
For families who cannot breastfeed, this research offers hope that future formula products might better replicate the natural protection that breast milk provides.