When people with type 1 diabetes undergo human islet cell transplantation. The islet cells from a donor pancreas produce robust amounts of insulin for the recipient, often permitting independence from insulin therapy.
However, the immune system tries to kill the new hard-working islets.
A person who has the transplant procedure must take powerful immunosuppressive drugs to prevent their bodies from rejecting the cells.
However, the drugs are toxic to the new islet cells and put patients at risk for infections and cancer.
Now, the researchers have found a way to trick the immune system of mice into believing those transplanted islets are its own cells.
This new technique eliminated the need for the immunosuppressive drugs in mice with chemically induced diabetes after they had islet transplantation.
"We made the recipient feel that the donor cells are their own. This technique is a highly attractive potential therapy for human islet cell transplantation," said Stephen Miller, co-principal investigator and the Judy Gugenheim Research Professor of Microbiology-Immunology at the Feinberg School.
In the study, the researchers took a type of white blood cell from the islet donor's spleen, called splenocytes, and treated them with a chemical that masked the cells' identity.
They then injected these chemically treated cells into diabetic mice before and after the mice underwent islet cell transplantation.
As a result, the immune system of the mice didn't try to reject the cells, because it didn't perceive them as foreign and dangerous.
When the same test was done without pre-treated cells, the immune system rejected the transplanted islets within 15 days.
The findings were reported in the journal Proceedings of the National Academy of Science in the fall.