| First Author | McCaughtry TM | Year | 2007 |
| Journal | J Exp Med | Volume | 204 |
| Issue | 11 | Pages | 2513-20 |
| PubMed ID | 17908937 | Mgi Jnum | J:126924 |
| Mgi Id | MGI:3762311 | Doi | 10.1084/jem.20070601 |
| Citation | McCaughtry TM, et al. (2007) Thymic emigration revisited. J Exp Med 204(11):2513-20 |
| abstractText | Conventional alphabeta T cell precursors undergo positive selection in the thymic cortex. When this is successful, they migrate to the medulla and are exposed to tissue-specific antigens (TSA) for purposes of central tolerance, and they undergo maturation to become functionally responsive T cells. It is commonly understood that thymocytes spend up to 2 wk in the medulla undergoing these final maturation steps before emigrating to peripheral lymphoid tissues. In addition, emigration is thought to occur via a stochastic mechanism whereby some progenitors leave early and others leave late-a so-called 'lucky dip' process. However, recent research has revealed that medullary thymocytes are a heterogeneous mix of naive alphabeta T cell precursors, memory T cells, natural killer T cells, and regulatory T cells. Given this, we revisited the question of how long it takes naive alphabeta T cell precursors to emigrate. We combined the following three approaches to study this question: BrdU labeling, intrathymic injection of a cellular tag, and RAG2p-GFP reporter mice. We established that, on average, naive alphabeta T cell precursors emigrate only 4-5 d after becoming single-positive (SP) thymocytes. Furthermore, emigration occurs via a strict 'conveyor belt' mechanism, where the oldest thymocytes leave first. |
