How is the immunity of a mother transferred to her baby?

One of the most effective interventions in reducing infectious diseases in the world, vaccination still has limited effectiveness to protect a group of patients, newborns. At present, a study based at the Ragon Institute of the MGH, MIT and Harvard has determined how immunity induced by a pregnant woman's vaccine is transferred to her child, which has implications for the development of more effective maternal vaccines. The report will be published in the June 27 issue of Cell and receives the early online version.

"Newborns come into the world the first day of their lives with a whole new immune system that, like the children themselves, must learn to cope with the beneficial and harmful microbes in their environment," says Galit Alter, Ph.D. D., Ragon Institute and Massachusetts General Hospital (MGH) Department of Medicine, co-lead author of Cell paper. "To help the newborn's immune system learn to distinguish between friends and foes, mothers transfer antibodies to their infants via the placenta." The rules that the placenta performs this essential function are unknown, but if they are decoded, they could allow more powerful vaccines to protect these most valuable patients. "

While maternal antibodies against certain diseases such as measles can be transferred from the mother to the newborn, providing some protection until the child is old enough to become pregnant. From an individual vaccination, antibodies directed against other serious diseases such as polio are transferred with less efficiency. To investigate the mechanisms by which antibodies are transferred from mother to child, Alter and his team, including co-lead author Laura Riley, MD, formerly with the Department of Obstetrics and Gynecology at the MGH and currently Chair of the Obstetrics and Gynecology Committee of Weill Cornell Medicine and NewYork-Presbyterian / Weill Cornell Medical Center – have used a new tool called serology system to compare the amount and quality of anti-pertussis antibodies in samples of mothers' blood and umbilical cords carrying blood, nutrients and immune factors from the placenta to the baby.

Their investigation revealed that the placenta is preferably screened and delivers antibodies to the infant that activate NK (Natural Killer) cells, key components of the innate immune system. While many important immune cells are too immature in newborns to provide effective protection, NK cells are among the most abundant and functional immune cells in the first days of life. The team found a similar preference for placental transfer of NK-activating antibodies against influenza and respiratory syncytial virus, a common childhood disease, and also identified features of antibodies that appear to regulate placental selection, characteristics that could eventually be incorporated into new generation vaccines. with better antibody transfer from mother to child.

Lead co-author Riley, Riley, said, "We will now have the opportunity to create better maternal vaccines and deliver them at the ideal time of pregnancy to maximize protection for newborns when they are the most vulnerable. . " Riley is a member of the Scientific Advisory Board of the Sabin Vaccine Institute, a leading advocate for making vaccinations more accessible around the world. She and Alter will actively explore other aspects of maternal immunity: the child to pave the way for the development of improved vaccines for the mother.