Immunoglobulin-like nature of the alpha-chain of a human T-cell antigen/MHC receptor.
Immunoglobulin-like nature of the alpha-chain of a human T-cell antigen/MHC receptor.
复制标题
人类 T 细胞抗原/MHC 受体 α 链的免疫球蛋白样性质。
作者：
Hannum,CH;Kappler,JW;Trowbridge,IS;Marrack,P;Freed,JH
尽管T细胞与特定抗原结合的受体可以像免疫球蛋白一样区分结构上仅略有不同的抗原，但它的独特之处在于只能结合主要组织相容性复合体(MHC限制)1-4的一种自身蛋白识别抗原。该受体是通过使用针对受体独特型5-7的单抗在小鼠和人身上鉴定和鉴定的，它由两个二硫键连接的多肽组成，一个是酸性α链，另一个是中性到微碱性的β链5、8、9。多肽图谱表明，与免疫球蛋白一样，这两条链对于不同特异性的受体是不同的。最近在小鼠和人的免疫球蛋白样分子13-15中发现了T细胞来源的cDNA克隆。这些克隆是通过从人T细胞肿瘤中分离的β链的部分N端蛋白序列来鉴定来自β链基因。我们已经提纯了人T细胞白血病细胞系HPB-MLT受体的α-链和β-链，并测定了这两条链衍生的几个胰蛋白酶多肽的氨基酸序列。我们的结果进一步证实了先前报道的克隆编码β链。α链肽的序列确定这是另一条免疫球蛋白样多肽链。特别引人注目的是一种α链肽，它与免疫球蛋白J段和T细胞受体β链的保守部分具有高度同源性。令人惊讶的是，α链肽与两个重叠的小鼠α链克隆预测的序列几乎没有相似之处。
Although the receptor with which T cells bind specific antigen can, like immunoglobulin, distinguish between antigens which differ only slightly in structure, it is unique in recognizing antigen only in conjunction with one of the self proteins of the major histocompatibility complex (MHC restriction)1–4. The receptor was identified and characterized in mouse and man by using monoclonal antibodies to receptor idiotypes5–7, and consists of two disulphide-linked polypeptides, an acidicα-chain and a neutral to slightly basicβ-chain5,8,9. Peptide maps have shown that, like immunoglobulin, both chains vary for receptors of different specificities10–12. T-cell-derived cDNA clones have recently been identified in mouse and man encoding immunoglobulin-like molecules13–15. These were identified as derived fromβ-chain genes through a partial N-terminal protein sequence of theβ-chain isolated from a human T-cell tumour16. We have now purified theα- andβ-chains of the receptor of the human T-cell leukaemia line HPB-MLT, and have determined the amino acid sequence of several tryptic peptides derived from each chain. Our results further confirm that the previously reported cDNA clones encodeβ-chains. The sequence of theα-chain peptides identify this as another immunoglobulin-like polypeptide chain. Particularly striking was anα-chain peptide with high homology to the conserved portion of the immunoglobulin J segment and T-cell receptorβ-chains. Surprisingly, theα-chain peptides show little similarity to the sequence predicted by two overlapping putative murineα-chain cDNA clones17.