Certified Professionals: Cd4⁺Cd25⁺ Suppressor T Cells

Although negative selection in the thymus and induction of anergy in the periphery have been widely accepted as mechanisms for controlling autoreactivity, much less attention has been devoted to the role of suppressor T cells in mediating dominant immunologic self-tolerance. In 1995, Sakaguchi et al. 1,2 made the seminal observation that the transfer of CD4⁺ T cells which had been depleted of the minor subpopulation (10%) of cells that coexpressed the IL-2 receptor (IL-2R) α-chain (CD25) to nu/nu recipients induced organ-specific autoimmune disease in the majority of recipients. Cotransfer of CD4⁺CD25⁺ cells with the CD4⁺CD25⁻ cells prevented the development of disease. The CD4⁺CD25⁺ population was also shown to be solely responsible for the prevention of autoimmunity observed after mice are thymectomized on the third day of life...