Helping the Body Tolerate Foreign Cells
A research team led by Aldo A. Rossini, M.D., director of diabetes care at the University of Massachusetts, has successfully transplanted islet cells from mouse to mouse without using immunosuppressive drugs.
Islet-cell transplantation has long been recognized as a potential cure for diabetes, but success has been limited. The stumbling block has been the body’s immune system, which will attack the donated cells unless they are protected.
Protection traditionally has been approached in two ways: physically isolating the cells from the immune system within membranes or capsules, or by giving the patient drugs to suppress the immune system. Encapsulation is under development with varying levels of success, and immunosuppression, while proven to work, subjects the recipient to adverse side effects.
The new technique “trains” the recipient’s body to accept the donated cells as if they were its own. White blood cells from donor mice were treated to remove the T cells, which are the major defense mechanisms against foreign bodies. In some experiments, the recipient mice also received an antibody that interrupts the natural stimulation of T cells.
Using the treated white blood cells alone or in combination with the antibody, the team was able to achieve indefinite survival of the transplanted islet cells. The recipients’ immune systems had learned to tolerate the foreign cells.
Dr. Rossini’s program is one of the 14 Diabetes Interdisciplinary Research Programs, funded jointly by the Juvenile Diabetes Foundation and the U.S. National Institute of Diabetes and Digestive and Kidney Diseases.