Specialized cells maintain healthy pregnancy by teaching the mother’s immune system not to attack developing fetus

What is the News?

A study published in Science Immunology has talked about the role of specialized “educator cells” in maintaining healthy pregnancy.

About the Study:

1. Scientists have conducted this study to understand how the immune system generally learns what to attack and what not to attack.
2. This is because the immune system is known to protect the body from invaders such as infections and cancers. 
3. But the immune system does not target one’s own organs or tissues or in the case of pregnancy, the developing fetus.
   • A fetus shares a blood supply and immune system with its mother. But the fetus is genetically different from the mother, and it also develops specialized organs like the placenta that might seem foreign to the mother’s immune system. 

Key Findings of the study:

1. Scientists have found there is a process known as immune self-education which happens in an organ called the thymus, specialized “educator cells”.
2. These specialized educator cells teach developing immune cells what not to attack by showing off a diverse array of the body’s own proteins. Essentially, this process teaches immune cells what constitutes “self”.
   • During pregnancy, these cells teach the mother’s immune system to recognize the developing fetus as part of her “self,” protecting it from being attacked as something “other”.
3. But these educator cells require a unique protein called the autoimmune regulator, or Aire, to teach the complete curriculum of the body’s own proteins. Any mutations in Aire lead to a devastating autoimmune disease.
4. There are also extrathymic Aire-expressing cells or eTACs which reside outside the thymus. They are predominantly in the lymph nodes and spleen. These cells are also essential for protecting pregnancy. In absence of eTACs, the mother’s immune system gets overactivated and attacks the fetus.

Significance of this study:

1. Pregnancy complications like miscarriage are common. But the cause is frequently a mystery. 
2. Hence, understanding how the immune system works to protect pregnancy may help scientists and doctors better identify, and hopefully prevent or treat, more of these pregnancy complications.