Immune signalling at the maternal-fetal interface and trophoblast differentiation.

In this review the afferent and efferent signals involved in immune signalling at the maternal-fetal interface are highlighted in the light of recent information. MHC antigen expression is reviewed. Immunizing mothers against class I and II MHC antigens can prevent spontaneous fetal resorption in mice. In addition, the CSF family of cytokines is not only secreted in placental tissues, but also play a role in trophoblast proliferation and differentiation. GM-CSF in particular appears to promote trophoblast syncytialization and the synthesis of human chorionic gonadotropin and human placental lactogen. Recent knock-out experiments indicate that CSF-1 is essential for complete fertility. Finally, the fact that the CSF cytokines promote HIV release from macrophages indicates that the knowledge gained in this area could lead to a better understanding of the transmission of the HIV virus from the mother to the fetus through the trophoblast.