Itano A, Kioussis D, Robey E
Department of Molecular and Cell Biology, University of California, Berkeley 94720.
Proc Natl Acad Sci U S A. 1994 Jan 4;91(1):220-4. doi: 10.1073/pnas.91.1.220.
The mechanism by which an initially uncommitted cell chooses between alternative fates is a central issue in developmental biology. In the mammalian thymus, CD4 helper T cells and CD8 cytotoxic T cells arise from a common precursor that expresses both CD4 and CD8. The choice between the CD4 and CD8 lineage is linked to the specificity of the T-cell antigen receptor expressed by a thymocyte, but whether lineage commitment is stochastic or instructed has not been definitively resolved. We present evidence that expression of a constitutive CD8 transgene during thymic selection permits development of mature CD4 cells bearing the class I-restricted F5 T-cell antigen receptor. These results suggest that there is a stochastic component to the development of class I major histocompatibility complex-restricted T cells.
一个最初未定向的细胞在不同命运之间进行选择的机制是发育生物学中的核心问题。在哺乳动物胸腺中,CD4辅助性T细胞和CD8细胞毒性T细胞源自共同的前体细胞,该前体细胞同时表达CD4和CD8。CD4和CD8谱系之间的选择与胸腺细胞所表达的T细胞抗原受体的特异性相关,但谱系定向是随机的还是受指令调控的尚未得到明确解决。我们提供的证据表明,在胸腺选择过程中组成型CD8转基因的表达允许携带I类限制性F5 T细胞抗原受体的成熟CD4细胞发育。这些结果表明,I类主要组织相容性复合体限制性T细胞的发育存在随机成分。