Raulet D H, Garman R D, Saito H, Tonegawa S
Nature. 1985;314(6006):103-7. doi: 10.1038/314103a0.
In contrast to B cells or their antibody products, T lymphocytes have a dual specificity, for both the eliciting foreign antigen and for polymorphic determinants on cell surface glycoproteins encoded in the major histocompatibility complex (MHC restriction). The recent identification of T-cell receptor glycoproteins as well as the genes encoding T-cell receptor subunits will help to elucidate whether MHC proteins and foreign antigens are recognized by two T-cell receptors or by a single receptor. An important feature of MHC restriction is that it appears to be largely acquired by a differentiating T-cell population under the influence of MHC antigens expressed in the thymus, suggesting that precursor T cells are selected on the basis of their reactivity with MHC determinants expressed in the host thymus. To understand this process of 'thymus education', knowledge of the developmental regulation of T-cell receptor gene expression is necessary. Here we report that whereas messenger RNAs encoding the beta-and gamma-subunits are relatively abundant in immature thymocytes, alpha mRNA levels are very low. Interestingly, whereas alpha mRNA levels increase during further development and beta mRNA levels stay roughly constant, gamma mRNA falls to very low levels in mature T cells, suggesting a role for the gamma gene in T-cell differentiation.
与B细胞或其抗体产物不同，T淋巴细胞具有双重特异性，既能识别引发免疫反应的外来抗原，又能识别主要组织相容性复合体（MHC限制）编码的细胞表面糖蛋白上的多态性决定簇。最近对T细胞受体糖蛋白以及编码T细胞受体亚基的基因的鉴定，将有助于阐明MHC蛋白和外来抗原是由两种T细胞受体识别，还是由单一受体识别。MHC限制的一个重要特征是，它似乎在很大程度上是由分化中的T细胞群体在胸腺中表达的MHC抗原的影响下获得的，这表明前体T细胞是根据它们与宿主胸腺中表达的MHC决定簇的反应性来选择的。为了理解这种“胸腺教育”过程，有必要了解T细胞受体基因表达的发育调控。我们在此报告，虽然编码β和γ亚基的信使核糖核酸在未成熟胸腺细胞中相对丰富，但α信使核糖核酸水平非常低。有趣的是，虽然α信使核糖核酸水平在进一步发育过程中增加，β信使核糖核酸水平大致保持恒定，但γ信使核糖核酸在成熟T细胞中降至非常低的水平，这表明γ基因在T细胞分化中起作用。
