Broodmares often lose their pregnancies within the first few weeks after conception. The reason is unknown, but research at the University of Veterinary Medicine, Vienna, suggests a particular class of blood cells and the mare’s immune system may be involved.
The fertilized egg, or conceptus, contains DNA from the stallion as well as the mare, which means it must somehow avoid being recognized and attacked by the mare’s immune system. A particular class of immune cell, the regulatory T cells or Tregs (pronounced “tea regs”), might be important in maternal tolerance.
Researchers measured the proportion of Tregs in the blood of mares. The results suggest that high numbers of Tregs might somehow be required to suppress the mare’s natural immune reaction against the conceptus.
More research is needed to determine how this knowledge can be used to help maintain pregnancies.