Horst H J, Flad H D
Lymphokine Res. 1986;5 Suppl 1:S55-9.
Interleukin 2 (IL-2) receptors which are expressed in T-lymphocytes after antigenic or mitogenic stimulation have been measured with either 3H- or 125J-labelled IL-2 or with receptor antibodies (e.g. anti-Tac). We have developed a new method which allows the determination of endogenously bound IL-2, or of the IL-2 binding capacity, respectively. The method utilizes incubation of target cells with human natural highly purified IL-2. Total bound IL-2 is determined by a conventional 3H-thymidine incorporation assay. An additional step, differential dissociation, eliminates low affinity bound IL-2 so that the remaining high affinity bound IL-2 can be determined. In PHA stimulated mononuclear cells we have found that high affinity binding sites appear after one day at high concentration and disappear gradually after more than ten days of culture. Low affinity binding sites appeared first on day 2, but showed then similar kinetics. IL-2 binding capacity closely correlated with the ability of the cells to respond to exogenous highly purified human IL-2. Our results demonstrate that in vitro in healthy blood donors the expression of IL-2 binding sites is necessary to render the cells responsive to IL-2 and to induce polyclonal expansion. Pharmacological doses of hydrocortisone abolishes both, IL-2 binding and IL-2 response.
抗原或有丝分裂原刺激后在T淋巴细胞中表达的白细胞介素2（IL-2）受体，已通过用³H或¹²⁵I标记的IL-2或受体抗体（如抗Tac）进行检测。我们开发了一种新方法，该方法分别允许测定内源性结合的IL-2或IL-2结合能力。该方法利用靶细胞与人天然高度纯化的IL-2孵育。总结合的IL-2通过常规的³H-胸腺嘧啶核苷掺入试验测定。一个额外的步骤，差异解离，消除低亲和力结合的IL-2，以便可以测定剩余的高亲和力结合的IL-2。在PHA刺激的单核细胞中，我们发现高亲和力结合位点在高浓度下一天后出现，并在培养超过十天后逐渐消失。低亲和力结合位点在第2天首先出现，但随后显示出相似的动力学。IL-2结合能力与细胞对外源性高度纯化的人IL-2的反应能力密切相关。我们的结果表明，在健康献血者的体外，IL-2结合位点的表达是使细胞对IL-2作出反应并诱导多克隆扩增所必需的。药理剂量的氢化可的松消除了IL-2结合和IL-2反应。
