Some T cells may be a fetus’ best friend

During a healthy pregnancy, a woman’s immune system somehow manages to avoid attacking the fetus she’s carrying, even though it has plenty of foreign characteristics contributed by the father.

In the March Nature Immunology, researchers offer an explanation in experimental mice for this pivotal exercise of self-control: While pregnant, the animals overproduce a kind of T cell that reins in other immune cells that might target the fetus.