Passive transfer of maternal antibodies

Passive transfer of maternal antibodies is a **biological process** by which mothers provide their offspring with immune protection through the delivery of preformed antibodies. In humans, this occurs primarily via the **transplacental transport** of immunoglobulin G (**IgG**) during pregnancy, mediated by the neonatal Fc receptor (**FcRn**) expressed on placental cells. This mechanism provides immediate but temporary protection to the fetus and newborn against various pathogens until their own immune system matures. After birth, additional passive immunity is conferred through breast milk—mainly via secretory IgA—which protects mucosal surfaces. The effectiveness and duration of this protection depend on factors such as gestational age at birth, maternal health status, and specific pathogen exposure history. While essential for early-life defense against infections like measles, rubella, tetanus, and others[1][2][5], passively transferred maternal IgG can also interfere with an infant’s response to certain vaccines administered within the first year[2][3]. This process is not itself a molecular target but rather describes an important physiological phenomenon involving several molecules—most notably IgG and FcRn—and has significant implications for neonatal health strategies including vaccination timing. Note: "Passive transfer of maternal antibodies" refers to a physiological process rather than a discrete molecular target such as a receptor or enzyme; therefore it does not fit standard therapeutic target classifications.[1][2]

Other names

Maternal antibody transferMaternal passive immunityVertical transfer of antibodiesTransplacental antibody transfer