Regulatory CD4+ T cells and the control of autoimmune disease.

The immune system is a delicately balanced network of interacting cells. In recent years, the concept of immune regulation/suppression has been firmly established, and both natural and induced regulatory cells play vital roles in protection from autoimmune disease. Recent work has revealed the diverse nature of regulatory CD4+ T (Treg) cells and the molecules involved in their function. Innate and adaptive responses to infection are able to override the suppressive properties of such regulatory cells, whereas several reports point to deficiencies in regulatory cell function in autoimmune disease. Protocols have been developed that allow the expansion of Treg cells in vitro and their antigen-specific induction in vivo. A full understanding of Treg differentiation and function will facilitate the development of improved strategies for prevention and treatment of autoimmune diseases.