Roles of gamma delta T cells in pregnancy and pregnancy-related complications

A successful pregnancy is a complex and unique process comprised of discrete events, including embryo implantation, placentation, and parturition. To maintain the balance between maternal-fetal immune tolerance and resistance to infections, the maternal immune system must have a high degree of stage-dependent plasticity throughout the period of pregnancy. Innate immunity is the frontline force for the establishment of early anti-infection and tolerance mechanisms in mammals. Belonging to the innate immune system, a subset of T cells called gamma delta T cells (based on gamma delta T cell receptors) are the main participants in immune surveillance and immune defense. Unlike traditional alpha beta T cells, gamma delta T cells are regarded as a bridge between innate immunity and acquired immunity. In this review, we summarize current knowledge on the functional plasticity of gamma delta T cells during pregnancy. Furthermore, we discuss the roles of gamma delta T cells in pathological pregnancies.