Missing link in human fetal immunity: fetal dendritic cells orchestrate prenatal T cell immune suppression

Developing fetus during gestation encounters variable immune stimulators, including semi-alloantigen from maternal cells, ingested amniotic fluid, food antigens, and microbes. Likewise, the expression of different histocompatibility molecules between mother and fetus can coexist for months without mutual rejection. In fetal immune system, how antigen-presenting cells (APC) interacting with T cells in response to foreign or self-antigen results in mutual tolerance remains unclear.