WASHINGTON, D.C., April 29 A special type of dendritic cell unusual for its capacity to promote the swift death of T cells appears to prevent diabetes, according to pre-clinical studies performed at the University of Pittsburgh's Thomas E. Starzl Transplantation Institute. The researchers are now taking steps to develop a potential clinical therapy that involves a genetically engineered version of these cells, they reported at the American Transplant Congress (ATC), Transplant 2002, at the Marriott Wardman Park Hotel in Washington, D.C.
In diabetes, a patient's own immune system T cells invade and destroy the body's insulin- producing cells, the islets of Langerhans, which are located in the pancreas. Normally T cells are engaged to attack outside foreign invaders, like a transplanted organ, when antigen-presenting cells, such as dendritic cells, identify and present these foreign substances to the T cells. Dendritic cells are found in all tissue but exist in far fewer numbers than T cells, which, when stimulated to attack, also proliferate.
While most dendritic cells originate in bone marrow, the special dendritic cell the Pitt researchers discovered in previous studies of transplant tolerance originates in the liver. Moreover, instead of causing T cells to proliferate, they found that this dendritic cell, called B220+DC, caused the T cells to die, through a process called apoptosis, and at a rapid rate.
Because T cells are the main antagonists in diabetes, Lina Lu, M.D., research associate professor of surgery at the Thomas E. Starzl Transplantation Institute, and colleagues took their previous discovery of this unique cell to see if it had an impact on the progression of diabetes.
Using a type of mouse that develops diabetes within weeks of gestation, the research team treated some mice with B220+ dendritic cells while a set of control animals received no treatment at all. The mice that did not receive the treatment all d
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Contact: Lisa Rossi
412-647-3555
University of Pittsburgh Medical Center
29-Apr-2002