Low and high affinity cellular receptors for interleukin 2. Implications for the level of Tac antigen.
Low and high affinity cellular receptors for interleukin 2. Implications for the level of Tac antigen.
复制标题
白细胞介素2的低亲和力细胞受体。对TAC抗原水平的影响。
DOI：
10.1084/jem.160.4.1126
复制
发表时间：
1984-10-01
影响因子：
15.3
通讯作者：
Rusk, C M
中科院分区：
文献类型：
--
作者：
Robb, R J;Greene, W C;Rusk, C M
白介素2通过与高亲和力细胞表面受体的相互作用促进T细胞的增殖。该受体是一种55,000摩尔重量的糖蛋白，也可被鼠源性单抗抗Tac识别。然而，与放射性标记的IL-2和抗Tac的定量结合研究最初表明每个细胞的抗体结合位点比IL-2结合位点多得多。将IL-2结合分析扩展到比T细胞增殖反应所需浓度高几千倍的浓度，表明存在一类(或几类)低亲和力IL-2结合位点。包括低亲和力的IL-2结合大大减少了配体结合试验中的定量差异。低亲和力结合以及高亲和力相互作用与Tac分子有关的发现表明，抗体可以基本上或完全阻断整个IL-2结合谱，并且IL-2反过来可以阻断所有放射性标记的抗Tac结合。在激活的T细胞、几个人和小鼠T细胞株以及两例Tac阳性的B细胞上发现了低亲和力位点。导致亲和力差异的低亲和力IL-2结合位点的生理作用和Tac蛋白中的分子变化仍有待研究。
Interleukin 2 promotes proliferation of T cells by virtue of its interaction with a high-affinity cell surface receptor. This receptor is a 55,000 mol wt glycoprotein that is also recognized by the murine monoclonal antibody, anti-Tac. Quantitative binding studies with radiolabeled IL-2 and anti-Tac, however, initially indicated far more antibody binding sites per cell than IL-2 binding sites. Extension of the IL-2 binding analysis to concentrations several thousand-fold higher than that necessary for the T cell proliferative response demonstrated the existence of a class (or classes) of low-affinity IL-2 binding sites. Inclusion of the low-affinity IL-2 binding greatly reduced the quantitative discrepancy in the ligand binding assays. That the low-affinity binding, as well as the high-affinity interaction, was associated with the Tac molecule was indicated by the finding that the antibody could substantially or totally block the entire spectrum of IL- 2 binding and by the finding that IL-2 could in turn block all radiolabeled anti-Tac binding. The low-affinity sites were found on activated T cells, several human and murine T cell lines and two examples of Tac-positive B cells. The physiological role of the low- affinity IL-2 binding sites and the molecular changes in the Tac protein that give rise to the affinity differences remain open to investigation.