Ashwell J D, Robb R J, Malek T R
J Immunol. 1986 Oct 15;137(8):2572-8.
The interleukin 2 (IL 2) receptor on T lymphocytes can be upregulated by a variety of stimuli including antigen, lectin, and IL 2 itself. In this report, the direct binding of radiolabeled IL 2 and a quantitative bioassay of T cell responsiveness to IL 2 were used to determine the biological significance of upregulation of the murine IL 2 receptor. Antigen and lectin, and to a lesser extent IL 2, were found to cause an increase in the expression of the high affinity form of the IL 2 receptor on both a T cell clone and concanavalin A-induced T cell blasts. A 2-day stimulation with antigen resulted in an increase in the sensitivity of the T cell clone to IL 2, whereas activation with IL 2 caused a decrease in the sensitivity of these cells to subsequent stimulation with IL 2. Comparison of the direct binding and the functional data revealed that IL 2-preactivated T cells required a greater number of occupied high affinity IL 2 receptors to achieve a given fractional response than did unactivated T cells. These observations suggest that the sensitivity with which a T cell responds to IL 2 is not determined solely by the number of high affinity IL 2 receptors it bears.
T淋巴细胞上的白细胞介素2（IL-2）受体可被多种刺激上调，包括抗原、凝集素以及IL-2自身。在本报告中，利用放射性标记的IL-2的直接结合以及T细胞对IL-2反应性的定量生物测定，来确定小鼠IL-2受体上调的生物学意义。发现抗原和凝集素，以及程度较轻的IL-2，都会导致T细胞克隆和伴刀豆球蛋白A诱导的T细胞母细胞上高亲和力形式的IL-2受体表达增加。用抗原进行2天的刺激会导致T细胞克隆对IL-2的敏感性增加，而用IL-2激活则会导致这些细胞对随后IL-2刺激的敏感性降低。直接结合数据和功能数据的比较表明，与未激活的T细胞相比，IL-2预激活的T细胞需要更多数量的占据的高亲和力IL-2受体才能达到给定的部分反应。这些观察结果表明，T细胞对IL-2的反应敏感性并非仅由其携带的高亲和力IL-2受体数量决定。
