Transferring part of an insulin gene into liver cells triggers a specific immune response that protects mice from one form of diabetes.

Type 1 diabetes occurs when T cells target and kill insulin-producing islet cells in the pancreas. Maria Grazia Roncarolo of Stanford University in California and her team transferred a gene fragment encoding some of the insulin B chain into the livers of mice engineered to develop this disease, and monitored the effects. Islet cells lived for up to 33 weeks after treatment of animals in a prediabetic state. In untreated mice, around 80% of insulin-producing cells were destroyed. The transfer, in combination with an antibody, reversed symptoms in mice that had developed diabetes.

The gene fragment stimulated regulatory T cells that are specific for insulin, suppressing the insulin-attacking T cells.

Sci. Transl. Med. 7, 289ra81 (2015)