Onset of TCR-β gene rearrangement and role of TCR-β expression during CD3-CD4-CD8- thymocyte differentiation

Abstract

TCR-β gene rearrangement or expression is necessary and sufficient for the progression of early αβ thymocyte differentiation from the CD3-CD4- CD8- triple negative (TN)3 to the CD4+CD8+ double positive stage. The onset of TCR-β rearrangement is currently thought to occur gradually. Some thymocytes were reported to be rearranged at the earliest (CD44+CD25-) TN stage, whereas other thymocytes did not initiate TCR-β rearrangement until the latest (CD44-CD25-) TN stage. Here, we have isolated subsets of TN thymocytes on the basis of surface expression of CD44 and CD25, with c-kit as an additional marker. We present a revised model of early T cell development in which TCR-β and TCR-γ rearrangemen..