NEW YORK, June 7, 2012 Researchers at NYU School of Medicine have made an important discovery that partially answers the long-standing question of why a mother's immune system does not reject a developing fetus as foreign tissue.
"Our manuscript addresses a fundamental question in the fields of transplantation immunology and reproductive biology, namely, how do the fetus and placenta, which express antigens that are disparate from the mother, avoid being rejected by the maternal immune system during pregnancy?" explained lead investigator Adrian Erlebacher, MD, PhD, associate professor of pathology and a member of the NYU Cancer Institute at NYU Langone Medical Center. "What we found was completely unexpected at every level."
The researchers discovered that embryo implantation sets off a process that ultimately turns off a key pathway required for the immune system to attack foreign bodies. As a result, immune cells are never recruited to the site of implantation and therefore cannot harm the developing fetus.
The study, funded by grants from the National Institutes of Health and the American Cancer Society, appears in the June 8 issue of Science.
A central feature of the body's natural immune defense against transplanted foreign tissues and pathogens is the production of chemokines as a result of the local inflammatory response. The chemokines recruit various kinds of immune cells, including activated T cells, which accumulate and attack the tissue or pathogen. The chemokine-mediated recruitment of activated T cells to sites of inflammation is an integral part of the immune response.
During pregnancy however, the foreign antigens of the developing fetus and the placenta come into direct contact with cells of the maternal immune system, but fail to evoke the typical tissue rejection response seen with organ transplants.
Several years ago, Erlebacher and his research team found that T cells, poi
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NYU Langone Medical Center / New York University School of Medicine