Pregnancy puzzle solved
4 May 2011 by Evoluted New Media
Rather than rejecting the foetus and placenta because it contains paternal proteins, the maternal immune system tolerates paternal antigens and even harnesses the immune interaction to promote foetal development
Rather than rejecting the foetus and placenta because it contains paternal proteins, the maternal immune system tolerates paternal antigens and even harnesses the immune interaction to promote foetal development
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Instead of rejecting a foetus, mum tolerates dad to ensure a healthy pregnancy |
This new understanding of the fundamental biology behind the relationship between the placenta and the immune system may provide new insights into pregnancy disorders such as recurrent miscarriage, pre-eclampsia and foetal growth restriction.
“This paradox has puzzled scientists for decades and understanding how the foetus evaded rejection, except in severe pregnancy complications, has remained elusive,” said Dr Myriam Hemberger of the Babraham Institute.
“Our findings show that paternal antigens on foetal trophoblast cells, which form in the placenta and are therefore in direct contact with maternal tissue, help to transform the uterus for robust placental and foetal growth,” Hemberger added. “This is essential for reproductive success.”
The mother’s immune cells are instructed by the father’s genes to create the best uterine conditions for the developing foetus, remodelling the blood supply to optimise nourishment and safeguarding the foetus from rejection.
Specific combinations of genes from the paternal immune system – and their target receptors on maternal immune cells – favourably affect blood supply and growth of the foetus. Specialised natural killer cells in the uterus (uNK) play a key role at the maternal-foetal boundary when fertilised embryo implants, adapting the uterine blood vessels to nourish the foetus.
Certain associations between uKN and paternal immune genes (MHC) signatures have been linked with a likelihood of developing pre-eclampsia and recurrent miscarriage.
The mouse model used has a direct analogy to human pregnancy and will shed light on the precise factors and pathways that are important for a healthy pregnancy and optimal intrauterine development.
“What is most exciting is that by revealing similarities between human and mouse immunology during pregnancy, the research lays new foundations for using mouse genetics to test new ideas and hypotheses informed by human genetics data,” said Dr Francesco Colucci.
