Figure 3.

A schematic of cell-to-cell interactions during positive and negative selection in the thymus. Conventional T and iNKT cells develop in the thymus, and share DN T-cell precursors. However, positive selection of iNKT cells proceeds via interactions with haematopietic cells, while conventional T cells require thymic epithelium for the positive developmental signal. Negative selection of both conventional T and iNKT cells is mediated by thymic dendritic cells. Both conventional T and iNKT cells are exported to the periphery following successful thymic education; however, a subset of iNKT cells remain thymic residents. Thus, conventional T and iNKT cells have distinct cellular requirements during positive and negative selection.