Wilson A, MacDonald H R
Ludwig Institute for Cancer Research, Lausanne Branch, University of Lausanne, Epalinges, Switzerland.
Int Immunol. 1995 Oct;7(10):1659-64. doi: 10.1093/intimm/7.10.1659.
The mature TCR is composed of a clonotypic heterodimer (alpha beta or gamma delta) associated with the invariant CD3 components (gamma, delta, epsilon and zeta). There is now considerable evidence that more immature forms of the TCR-CD3 complex (consisting of either CD3 alone or CD3 associated with a heterodimer of TCR beta and pre-T alpha) can be expressed at the cell surface on early thymocytes. These pre-TCR complexes are believed to be necessary for the ordered progression of early T cell development. We have analyzed in detail the expression of both the pre-TCR and CD3 complex at various stages of adult thymus development. Our data indicate that all CD3 components are already expressed at the mRNA level by the earliest identifiable (CD4lo) thymic precursor. In contrast, genes encoding the pre-TCR complex (pre-T alpha and fully rearranged TCR beta) are first expressed at the CD44loCD25+CD4-CD8- stage. Detectable surface expression of both CD3 and TCR beta are delayed relative to expression of the corresponding genes, suggesting the existence of other (as yet unidentified) components of the pre-TCR complex.
成熟的T细胞受体（TCR）由一个克隆型异二聚体（αβ或γδ）与恒定的CD3成分（γ、δ、ε和ζ）组成。现在有大量证据表明，TCR-CD3复合物的更不成熟形式（单独由CD3组成或与TCRβ和前Tα异二聚体相关的CD3）可以在早期胸腺细胞的细胞表面表达。这些前TCR复合物被认为是早期T细胞发育有序进展所必需的。我们已经详细分析了成年胸腺发育各个阶段前TCR和CD3复合物的表达情况。我们的数据表明，最早可识别的（CD4低）胸腺前体在mRNA水平上已经表达了所有CD3成分。相比之下，编码前TCR复合物（前Tα和完全重排的TCRβ）的基因首先在CD44低CD25 + CD4 - CD8 - 阶段表达。相对于相应基因的表达，CD3和TCRβ的可检测表面表达延迟，这表明前TCR复合物存在其他（尚未确定）成分。
