Athens, Ga. The thymus gland is a critical component of the human immune system that is responsible for the development of T-lymphocytes, or T-cells, which help organize and lead the body's fighting forces against harmful organisms like bacteria and viruses.
The main body of the thymus lies beneath the breastbone in the upper chest. But scientists were surprised several years ago when two teams of researchers discovered that both mice and humans have extra thymus-like glands distributed throughout their necks.
Now, researchers at the University of Georgia have published findings in Nature Communications that reveal where these extra glands come from and help explain what roles the extra thymuses may play in the complex network of the body's natural defense systems.
"This was a really important question for me as a developmental biologist studying the thymus," said Nancy Manley, professor of genetics in UGA's Franklin College of Arts and Sciences and principal investigator for the project. "It would almost be akin to someone discovering that humans have extra heart tissue somewhere else in the body."
Manley and her team of researchers discovered that the small satellite thymuses, known as cervical thymi, have two distinct origins, and while it's not entirely clear if they play a major role in human health, the T-cells these thymi produce could be either helpful or harmful.
In the early phases of embryonic development, the cells that form the thymus come from the same cluster of cells that also form the parathyroid glands, which regulate the body's calcium balance. As the fetus develops, these cells separate and turn into distinct tissues, and the cells that make up the thymus move down near the heart while the parathyroid tissues remain in the neck near the thyroid gland.
During this dividing process, there are always a few cells that don't follow the normal path, sticking neither to the thymus n
|Contact: Nancy Manley|
University of Georgia