The new findings could help reduce miscarriages and pregnancy complications

Image of human fetuses Source: NEIL BROMHALL
One of the most confusing aspects of pregnancy is why the mother's immune system does not destroy a developing fetus because it is filled with foreign material, like an invading microorganism. Now, researchers have mastered a complex molecular "negotiating" mechanism that helps keep the fetus and mother safe until the fetus is born.
" complexity is staggering. Sumati Rajagopalan, an immunologist at the National Institute of Allergy and Infectious Diseases in Bethesda, Maryland, who was not involved in the study, said. Understanding this type of communication may ultimately help reduce miscarriages and other pregnancy complications, she added.
these pregnancy complications usually begin early in pregnancy, when the embryo is just beginning to enter the metamorphosis membrane, the endometrium. Sarah Teichmann, computational biologist at the Wellcome Sanger Institute in Cambridge, UK, said: "The mother-fetal interface is not yet clear, but it is essential for a successful pregnancy. As
, Teichmann and her colleagues decided to test the genetic activity of individual cells from mothers and fetuses during this time. The researchers analyzed 70,000 white blood cells, as well as cells in the placenta and membrane tissue of pregnant women who terminated their pregnancies between 6 and 14 weeks of pregnancy.
using single-cell transcription techniques, the researchers assessed the genetic activity of each cell, obtained a protein reading, and determined what each cell was.
researchers identified 35 types of cells, some new and some known, including embryonic cells that invade the mother's tissue, which help triggered the formation of blood vessels that connect the mother and fetus.
researchers also found several types of immune cells, including several so-called natural killer cells, which often destroy infected cells and tumor cells. The researchers then combed the existing protein interaction database to determine which cells interacted on the basis of these protein connections.
teichmann and her team found that invading embryonic cells stimulate maternal cells to produce immune cells that control the immune response. The researchers also realized that at least some of the natural killer cells in the mother's body are "peacekeepers" rather than "warriors" that prevent other immune cells from attacking the fetus and produce chemicals that promote fetal growth and vascular connections.
these natural killer cells are controlled to some extent by cells in the metamorphosis membrane called substation cells. "We can now see in detail how they communicate with each other," Teichmann said. "Our results also reveal the multi-layered mechanisms of the immune system that researchers didn't realize before, " she says. Teichmann
team reported the findings in the November 14 issue of the journal Nature.
Rajagopalan, said there were more interactions to explore. To that end, Teichmann's team has built an online database to help other researchers do just that. (Source: Zhao Xixi, China Science Daily)