EVIDENCE FOR MULTIVALENT STRUCTURE OF T-CELL ANTIGEN RECEPTOR COMPLEX
EVIDENCE FOR MULTIVALENT STRUCTURE OF T-CELL ANTIGEN RECEPTOR COMPLEX
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DOI：
10.1016/0161-5890(95)00046-h
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发表时间：
1995-08-01
影响因子：
3.6
通讯作者：
TERHORST, C
中科院分区：
文献类型：
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作者：
EXLEY, M;WILEMAN, T;TERHORST, C
已知T细胞抗原受体(α-β或γ-βTCR)与四种多肽(CD3-γ、β-、epsilon和Zeta)结合形成TCR-CD3复合体。虽然这六条链已经得到了很好的表征，但TCR-CD3络合物的分子质量和成分的化学计量目前尚不确定。我们分析了一株表达两种不同异源二聚体的T-T杂交瘤的TCR。当杂交瘤与针对Vα(10)Vβ(5.1)异二聚体的mAb(MR9.2)孵育时，根据mAbMR9.2和MR9.7(Vα(1)Vβ(1)特异性)，这两个异二聚体都从细胞表面消失。共调节Vα(1)、Vβ(1)和Vα(10)Vβ(5.1)的能力表明TCR复合体可能含有两个α-β-异源二聚体。密度梯度沉积分析为高阶TCR提供了进一步的证据。比较了TCR与B细胞抗原受体、VSV膜G蛋白以及可溶性标志蛋白的沉降型式。小鼠和人的最大细胞表面TCR沉积系数大大高于210 kDa单价α-β-伽马增量epsilon(2)zeta(2)结构预测的9-10s。TCR在温和的非离子洗涤剂中以大的18+/-3S复合体的形式沉淀，与一个443 kDa的标记蛋白共同迁移。相反，IgM B细胞抗原受体的最大沉降系数为10+/-3S，与预测的类似300 kDa的大小一致。综上所述，这些结果表明，T细胞抗原受体可能含有一个以上的α-β-异二聚体，它们可以被结合到一个最小的二价10链TCR-CD3复合体中(例如，α-β-Zeta Zeta-α-β)。
The T-cell antigen receptor (alpha beta or gamma delta TCR) is known to associate with four polypeptides (CD3 gamma, delta, epsilon and zeta) to form the TCR-CD3 complex. Although the six chains are well characterized, the molecular mass of the TCR-CD3 complex and stoichiometry of the components are currently uncertain. We analysed the TCR of a T-T hybridoma which expresses two distinct heterodimers. When the hybridoma was incubated with a mAb (MR9.2) specific for the V alpha(10)V beta(5.1) heterodimer, both of the heterodimers were lost from the cell surface, as measured with mAb MR9.2 and MR9.7 (V alpha(1)V beta(1)-specific). The ability to co-modulate V alpha(1)V beta(1) and v alpha(10)V beta(5.1) suggested that TCR complexes could contain two alpha beta-heterodimers. Density gradient sedimentation analysis provided further evidence for higher order TCR. The sedimentation patterns of the TCR were compared to that of the B-cell antigen receptor and the well-characterized VSV membrane G-protein as well as to soluble marker proteins. Maximal cell surface murine and human TCR sedimentation coefficients were substantially greater than the 9-10S predicted for a 210 kDa monovalent alpha beta gamma delta epsilon(2) zeta(2) structure. The TCR sedimented in mild non-ionic detergents as large 18 +/- 3S complexes co-migrating with a 443 kDa marker protein. In contrast, the IgM B-cell antigen receptor had a maximal sedimentation coefficient of 10 +/- 3S, consistent with a predicted size of similar to 300 kDa. Taken together, the results suggested that T-cell antigen receptors can contain more than one alpha beta-heterodimer which could be incorporated into a minimal divalent 10-chain TCR-CD3 complex (e.g. alpha beta gamma epsilon epsilon delta zeta zeta alpha beta).