Skip to main content
. Author manuscript; available in PMC: 2015 Mar 21.
Published in final edited form as: Annu Rev Immunol. 2014 Jan 22;32:283–321. doi: 10.1146/annurev-immunol-032712-100024

FIGURE 1.

FIGURE 1

Schematic of major stages of B and T cell development. Consult Table 1 for definition of stage phenotypes. The figure introduces key stages and emphasizes the parallelism between B cell development stages and αβ T lineage cell stages in terms of immunoreceptor gene rearrangement timing, proliferative bursts and major developmental checkpoints. Specific regulatory genes important for lineage specification are turned on during the intervals shown. Stages are defined by ability to discriminate phenotypes and do not represent uniform lengths of time or numbers of cell cycles. Note that the T cell program unlike the B cell program generates at least five distinct types of T cells within the thymus (in fact the TCRγδ cells are further subdivided, not shown). “Thymus settling” = thymus settling precursors, which are thought to be derived from “ALP” type common lymphoid precursors and/or from certain LMPP or other ELP type cells in vivo. All of these, and even myeloid specified cells, can respond when introduced into the thymus by developing into T cells.