Study Finds Tonsils Can Make T Cells
Posted on March 5, 2012
Researchers at Ohio State University have found that T lymphocytes, or T cells, can also develop in human tonsils. T cells, which are essential for effective immune responses, have been thought to be produced only in the thymus gland. The researchers say the discovery could improve stem-cell transplantation and the understanding of T-cell cancers and autoimmune diseases. Tonsillectomy, the removal of the tonsils, is a common surgical procedures in children in the United States.
The study used tonsil tissue obtained from children undergoing routine tonsillectomy at Nationwide Children’s Hospital in Columbus, and thymic tissue obtained from children undergoing thoracic surgery. T cells were identified at five distinct stages of development in the tonsil. These stages, identified using molecular signposts on the cells, were very similar to the stages of T-cell development in the thymus, although some differences were found. The study also discovered that the cells develop in a particular region of the tonsil, in areas near the fibrous scaffold of the tonsil. The findings were publsihed here in the Journal of Clinical Investigation.
Principal investigator Dr. Michael A. Caligiuri, director of Ohio State’s Comprehensive Cancer Center and CEO of the James Cancer Hospital and Solove Research Institute, says, "We've known for a long time that a functional thymus is necessary to develop a complete repertoire of T-cells, but whether a T-cell factory existed outside the thymus has been controversial. I believe our study answers that question. It is the first report to describe a comprehensive, stepwise model for T-cell development outside the thymus."
Caligiuri noted that it is still unclear whether T-cells that develop in the tonsil also mature there or whether they leave the tonsil to mature elsewhere.
Susan McClory, a graduate fellow in Caligiuri's laboratory, says, "The complete implications of this phenomenon for human health and disease are not entirely known. It could be important in the development of T-cell cancers and autoimmune diseases, or it might suggest a location for T-cell development when thymus function is poor. We hope to do additional studies to explore these possibilities."