Can Listeria pass the placenta?

Answered by Jason Smith

Listeria, a type of bacteria, has the ability to pass the placenta and reach the fetus. This can have serious consequences, as Listeria infection during pregnancy can lead to miscarriage, stillbirth, premature delivery, or severe illness in the newborn.

To understand how Listeria is able to cross the placenta, researchers have used animal models to study the interaction between the bacteria and the placental tissue. Two specific proteins of Listeria, called InlA and InlB, have been identified as key players in this process.

InlA and InlB are surface proteins produced by Listeria that allow the bacteria to adhere to and invade host cells. These proteins interact with specific receptors on the surface of host cells, enabling Listeria to gain entry into the cells and cause infection. In the case of the placenta, InlA interacts with a receptor called E-cadherin, while InlB interacts with a receptor called Met.

Through the interaction of InlA with E-cadherin, Listeria is able to adhere to and invade the placental tissue. E-cadherin is a protein that plays a crucial role in cell adhesion, particularly in the formation of tight junctions between cells. By binding to E-cadherin, InlA disrupts the integrity of these junctions, allowing Listeria to penetrate the placental barrier.

Similarly, the interaction between InlB and Met facilitates the crossing of Listeria through the placenta. Met, also known as hepatocyte growth factor receptor, is a cell surface receptor involved in cell migration and tissue development. The binding of InlB to Met triggers signaling pathways that promote the internalization of Listeria into placental cells, enabling the bacteria to reach the fetal side of the placenta.

These findings from animal models provide valuable insights into the mechanisms by which Listeria is able to pass the placenta. However, it is important to note that animal models may not fully reflect the complexity of human pregnancy and placental function. Further research is still needed to fully understand the precise mechanisms involved in Listeria’s ability to cross the placental barrier in humans.

Listeria has the ability to pass the placenta and reach the fetus, posing a significant risk to pregnant women and their unborn babies. The interaction between Listeria proteins InlA and InlB with specific receptors on the placental cells allows the bacteria to adhere to and invade the placental tissue, ultimately crossing the placenta to reach the fetus. Understanding these mechanisms is crucial in developing strategies to prevent and treat Listeria infections during pregnancy.