LSTM Immunology Forum: Maternal-Foetal immune tolerance mediated by HLA-G+ extravillous trophoblast cells in human pregnancy

News article 28 Nov 2013

The Immunology Forum met today (Monday, 25th December) at LSTM with a talk entitled: “Maternal-Foetal immune tolerance mediated by HLA-G+ extravillous trophoblast cells in human pregnancy ” delivered by Dr Tamara Tilburgs, of the Department of Stem Cell and Regenerative Biology, Harvard University.

Dr Tilburgs was introduced by Dr Pilar Requena and began her talk with a statement by Sir Peter Medawar, the winner of the 1960 Noble Prize in Physiology or Medicine, who first proposed the paradox that “the foetus is an allograft which is not rejected”. Dr. Tilburgs then explained that initially it was believed that maternal and fetal cells were physically separated or did not interact, but nowadays it is clear that the maternal immune system recognise the foetal alloantigens.  Dr. Tilburgs research is actually focused on studying the interactions between the foetal villous (VT) and extravillous trophoblasts (EVT) and the maternal leukocytes.

Dr. Tilburgs has set up a unique method to isolate and culture untouched EVT, based on the differential expression of HLA-G+. Using microarrays, they have characterized the gene-expression signatures in several of the cell subsets present in the first trimester placenta: EV, EVT and decidual stromal cells.

Dr Tilburgs has also looked at the interactions of EVTs with decidual lymphocytes, to discover which maternal lymphocytes interact with EVTs and what effects has this interaction on different immune cells. e.g., NK cells, Tregs or macrophages. After co-culturing in vitro EVTs with different immune cell subsets, they found no impact on NK cells and macrophages but an increased in FoxP3+ T cells. This suggests that EVT contributes to maternal-foetal tolerance.

The next step in Dr. Tamara Tilburgs research will be to study the role of viral infections in disrupting the maternal-foetal tolerance or how this tolerance might prevent clearance of placental infections.