Equine Pregnancy – How can immunology help?
The field of reproductive immunology has rapidly advanced in recent years, yet continues to raise a plethora of unanswered questions. Drawing from research on several species, a number of mechanisms have been attributed to aiding in the understanding of the ‘million dollar question’ – namely, how can a fetus avoid maternal immune rejection and survive throughout the gestation period, despite being genetically different from the mother?
Despite a number of studies concentrating on both mouse and human models of pregnancy, equine reproduction is also able to aid in such studies. In its own right, equine reproduction possesses unique qualities that are well suited to study the immune system during pregnancy. The ability to easily obtain the equine conceptus during early pregnancy without undue harm or distress to the mare is a clear advantage when studying equine pregnancy. This conceptus can then be used in future studies that will aid in the understanding of the immune system during pregnancy, consequently aiding in pregnancy success. In addition, the mechanisms attributed to maternal immune tolerance to the fetus are likely to be shared both intra- and inter-species.
The applications of increased understanding of equine reproduction are both wide and varied, including utilisation within the racehorse industry, which is financially lucrative. For example, a particular mating between a champion stallion and mare may be desirable in creating a foal with characteristics perfectly suited for racing. An inability to result in successful mating may be as a consequence of a variety of factors, including fetal chromosomal abnormalities, genetics or immunological. Therefore, an increased understanding of mechanisms resulting in maternal rejection of the fetus would greatly aid in enhancing fetal survival, which would be useful for a potential breeder.
The realisation that a pregnancy where the mare is carrying twins (which may be detected through a routine equine ultrasound) is not viable, perfectly highlights the benefits of an increased understanding of equine pregnancy. It is therefore a reasonable assumption that future studies will reveal additional information that will help to prevent pregnancy losses not just within equine reproduction, but across all species. With the rapidly advancing technologies available to aid in such studies, the currently ambiguous nature of the mechanisms involved in pregnancy may become apparent.
About the author: Miss Melissa Robbin BSc (Hons) is a PhD student at the The Royal Veterinary College, London, specialising in equine immunology.