Suppressive Cellular and Molecular Activities in Maternofetal Immune Interactions; Suppressor Cell Activity, Prostaglandins, and Alpha-Fetoproteins

Pregnancy has been termed an immunological “paradox” because the fetoplacental unit –although genetically and antigenically alien to its mother–is usually accepted by her as a “semi-allograft”. Several models have been proposed to explain this apparent paradox. BILLINGHAM’S (1964) concept of the fetoplacental unit as a semi-allograft is still valid form a purely genetic point of view, but otherwise has some shortcomings. First, in contrast to a grafted organ, a fetal “graft’s” blood circulation is structurally separated from that of the mother by a barrier in humans consisting of trophoblastic cells, fetal capillary endothelium, and basal membranes with mesenchymal cells in between (see REDLINE, this volume).