The Impact of IgG Transplacental Transfer on Early Life Immunity

Abstract

Pediatric vaccines have significantly reduced infectious disease–related infant mortality, but as protective immunity often requires several infant vaccine doses, maternally acquired Abs are critical to protect infants during the first months of life. Consequently, immunization of pregnant women is an important strategy not only to protect mothers from infection, but also to provide immunity to young infants. Nevertheless, maternal immunization can also negatively impact early life immunity. In fact, maternal Abs can interfere with the development of infant immune responses, although it is unclear whether such interference is clinically significant. Moreover, the transplacental transfer of maternal Ig therapeutics can be harmful to the fetus. Thus, the risk–benefit of maternal immunization for both the mother and the fetus should be carefully weighed. In addition, it is critical to fully understand the mechanisms by which IgG is transferred across the placenta to develop optimal maternal and infant immunization strategies.