New insight could improve vaccines that protect pregnant women and newborns

A team led by scientists at Duke Health has identified a cellular process that could lead to the development of safer and more effective vaccines that protect pregnant women and their newborns from dangerous infections.

Published online June 13 in the journal Cell, the researchers described a previously unidentified pathway of maternal-to-fetal antibody transfer, illustrating a potential way to leverage this process to control when and how certain antibodies are shared.

It has always been badumed that the types of maternal antibodies that cross the placenta up to the fetus, all the antibodies had the same chance of being transferred to the fetus.

This meant that it was impossible to direct certain antibodies across the placenta and towards the baby. Our study revealed that there appears to be a code on the antibody that determines which antibodies will be transferred more efficiently across the placenta. "

Lead author Sallie Permar, M.D., Ph.D., professor of pediatrics and member of the Duke Human Vaccine Institute

Permar and colleagues – including lead author Genevieve Fouda, Ph.D., and lead author David Martinez, Ph.D. – have studied two populations of HIV-infected pregnant women in the United States and Malawi, known to inhibit the transfer of antibodies to the fetus – not just the anti-HIV antibodies. This feature provided a unique circumstance for exploring a misunderstood process with implications for many common pathogens, including tetanus, pertussis, influenza and others.

Researchers have identified a sugar molecule that interacts with placental receptors, a previously unknown interaction of the antibody transfer process. The conclusion was corroborated in healthy women by another research team who published the same issue of Cell.

"We have shown that the efficiency of antibody transfer across the placenta is regulated in a differentiated manner," Permar said. "This idea could improve vaccine design for various infectious diseases to improve transfer of transplacental antibody to the fetus."

"Our results provide a roadmap of how antibodies cross the placenta for the baby," Martinez said. "We hope our results will be useful for developing antibody-based therapies that protect infants against infectious diseases early in their lives."