"How the Placenta Modifies Immune Responses to Safeguard the Fetus"

Researchers have discovered that the placenta protects the fetus by mimicking a viral attack, which activates a mild immune response without causing harm. This response is due to the production of interferon lambda, triggered by the placenta's use of Alu repeat RNA sequences from the genome that resemble viral RNA. This mechanism allows the placenta to maintain a protective state against real viruses while avoiding damage to itself or the fetus, revealing a novel aspect of immune system function during pregnancy.