Which type of T cells increases during pregnancy to help protect the fetus?

Treg cells, or regulatory T cells, play a crucial role in maintaining immune tolerance during pregnancy. They are instrumental in preventing the maternal immune system from attacking the developing fetus, which is genetically distinct due to contributions from both parents.

The increase in Treg cells during pregnancy helps to create a more tolerogenic environment, allowing for the successful implantation and growth of the fetus. These cells achieve this by secreting anti-inflammatory cytokines, inhibiting the activity of other immune cells, and promoting a favorable balance in the maternal immune response.

This protection is essential, as it ensures that the fetus can develop without being rejected by the mother's immune system, which would recognize paternal antigens as foreign. The presence and enhancement of Treg cells underscore their significant contribution to maternal-fetal tolerance and the overall health of both the mother and the developing fetus.