Placental Immune Defences – Protection Against Rejection and Infection


The placenta must not only provide nutrients and take care of fetal waste products, it also needs to protect the fetus from maternal immunological attacks while at the same time transmitting maternal immunoglobulins to ensure protection against infectious agents.

Keywords: placenta; trophoblast; pregnancy; fetal rejection; immunoglobulin

Figure 1.

Schematic picture of the attachment and implantation of the blastocyst. (a) The human blastocyst attaches to the uterine epithelium at day 6–7 and some cells start to form the syncytiotrophoblast. In mice, attachment of the blastocyst takes place around day 4. (b) During the process of implantation in humans (day 8), the invasive syncytiotrophoblast proliferates and actively pulls the blastocyst into the uterine wall.

Figure 2.

Schematic drawing of the human placenta and organization of the fetal membranes. The tree‐like structure of the chorionic villi constitutes the part of the human placenta where maternofetal exchange of nutrients and waste occurs. The yolk sac can be observed between the amnion and the chorion in early pregnancy. By the end of the third month, the amnion and chorion have fused.

Figure 3.

Schematic drawing of the mouse placenta and organization of the fetal membranes. The chorioallantoic placenta consists of the labyrinthine trophoblast (the area of maternofetal interdigitation) and the spongiotrophoblast. Giant trophoblast cells constitute the border to the maternal decidua basalis. In contrast to the human fetus, the mouse fetus is enclosed by the yolk sac.



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Further Reading

Cross JC (2005) Placental function in development and disease. Reproduction, Fertility and Development 18: 71–76.

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Petroff MG (2005) Immune interactions at the maternal‐fetal interface. Journal of Reproductive Immunology 68: 1–13.

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Liljander, Maria, Arvola, Marie, and Mattsson, Ragnar(Jan 2007) Placental Immune Defences – Protection Against Rejection and Infection. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0001438.pub2]