Figure 1. The role of dendritic cells in the thymus. DCs are positioned in the medullary region of the thymus, and acquire tissue-restricted antigens from mTECs (A) and circulating antigens from blood vessels (B). Some thymic DCs originate from periphery carrying antigens acquired from the peripheral tissue sites (C). The acquired antigens are presented to CD4⁺ thymocytes via MHCII (D) and CD8⁺ thymocytes via MHCI (E), and this presentation results in thymocyte apoptosis or Treg cell differentiation (F and G).