TCR

T Cells express T cell receptors (TCRs), which consist of invariant CD3γ, δ, ε, and ζ subunits complexed with highly variable TCRαβ or γδheterodimers.

invariant CD3γ, δ, ε, and ζ subunits
highly variable TCRαβ or γδ heterodimers.

T细胞的发育过程

3 Steps:

thymus settling;
lineage commitment and receptor assembly;
selection

cell migration to the thymus-向胸腺的迁移

only small numbers of precursors are thought to undertake this journey

Multiple precursor types

T lineage-restricted precursors (T谱系限制性前体)
multipotential lymphoid precursors （多潜能淋巴前体）
Info

T细胞来源于骨髓或胚肝淋巴样干细胞分化发育的早期T细胞系前体(early T lineage precursor, ETP)。ETP 从进入胸腺皮质后至离开胸腺前,均称胸腺细胞(thymocyte)。

Some lineage of T cells require strong signals for maturation, and the term “agonist selection”(激动剂选择) is used for the selection of regulatory T cells (T_regs) and innate-like T cell lineages.

from the cortex to the medulla

在成年个体中，胸腺产生T细胞的能力降低，外周T细胞数目主要通过成熟T细胞在中枢淋巴器官之外的分裂来维持。