In the past few years, there has been a flurry of discoveries and advancements in our understanding of how the thymus prepares T cells to exist at peace in normal healthy tissue: that is, to be self-tolerant. In the thymus, one of the main mechanisms of T-cell central tolerance is clonal deletion, although the selection of regulatory T cells is also important and is gaining enormous interest. In this Review, we discuss the emerging consensus about which models of clonal deletion are most physiological, and we review recent data that define the molecular mechanisms of central tolerance.
Bibliographical noteFunding Information:
This work was supported by the National Institutes of Health (United States) (to K.A.H.), and the Canadian Institutes of Health Research and the Alberta Heritage Foundation for Medical Research (Canada) (to T.A.B.).