Vidović D, Roglić M, McKune K, Guerder S, MacKay C, Dembić Z
Basel Institute for Immunology, Switzerland.
Nature. 1989 Aug 24;340(6235):646-50. doi: 10.1038/340646a0.
Distinct T-lymphocyte subsets recognize antigens in conjunction with different classes of major histocompatibility complex (MHC) glycoproteins using the T-cell receptor (TCR), a disulphide-linked heterodimer associated with the CD3 complex on the cell surface. In general, class I and class II MHC products provide a context for the recognition of foreign antigens by CD8+ and CD4+ T cells, respectively. This recognition seems to be largely dependent on alpha beta TCR heterodimers, whereas the function of the second gamma delta TCR, present on a minor subpopulation of cells, is still unknown. In the mouse, the existence of six cell-surface MHC class I products (K, D, L, Qa-1, Qa-2 and Tla) has been firmly established by serological, biochemical and genetic evidence. So far, only the most polymorphic of them, K, D and L ('classical' class I) have been reported as restriction elements for T-cell recognition of foreign antigens. The function of the relatively invariant Qa and Tla molecules remains unknown. We have made a T-helper cell hybridoma clone (DGT3) that recognizes synthetic copolymer poly(Glu50Tyr50) in the context of Qa-1 cell surface product, and has a CD4-CD8- phenotype. Our studies indicate that DGT3 cells express the gamma delta TCR on the cell surface, implicating its role in Qa-1-restricted antigen recognition. This is the first evidence that T cells can recognize foreign antigen in association with self Qa product, confirming that Qa molecules not only topologically, but also functionally, belong to the MHC.
不同的T淋巴细胞亚群利用T细胞受体（TCR）与不同类别的主要组织相容性复合体（MHC）糖蛋白结合来识别抗原，TCR是一种与细胞表面CD3复合体相关的二硫键连接的异二聚体。一般来说，I类和II类MHC产物分别为CD8 +和CD4 + T细胞识别外来抗原提供了背景。这种识别似乎在很大程度上依赖于αβTCR异二聚体，而存在于细胞亚群中的第二种γδTCR的功能仍然未知。在小鼠中，通过血清学、生物化学和遗传学证据已确凿证实存在六种细胞表面I类MHC产物（K、D、L、Qa - 1、Qa - 2和Tla）。到目前为止，只有其中多态性最高的K、D和L（“经典”I类）被报道为T细胞识别外来抗原的限制元件。相对不变的Qa和Tla分子的功能仍然未知。我们制备了一个T辅助细胞杂交瘤克隆（DGT3），它在Qa - 1细胞表面产物的背景下识别合成共聚物聚（Glu50Tyr50），并且具有CD4 - CD8 - 表型。我们的研究表明，DGT3细胞在细胞表面表达γδTCR，这暗示了其在Qa - 1限制的抗原识别中的作用。这是T细胞可以识别与自身Qa产物相关的外来抗原的首个证据，证实了Qa分子不仅在拓扑结构上，而且在功能上都属于MHC。
