Interleukin 1 alpha and interleukin 1 beta bind to the same receptor on T cells.
Interleukin 1 alpha and interleukin 1 beta bind to the same receptor on T cells.
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白细胞介素 1 α 和白细胞介素 1 β 与 T 细胞上的相同受体结合。
作者：
P. L. Kilian;K. Kaffka;A. Stern;D. Woehle;W. Benjamin;T. Dechiara;U. Gubler;J. Farrar;S. Mizel;P. Lomedico
Pure，E.用125 I标记来源于大肠杆菌的重组鼠白细胞介素1 α（IL 1 α）并用于受体结合研究。~（125）I-IL-1与小鼠EL-4胸腺瘤细胞具有特异性结合。在4 ℃下进行的结合研究的Scatchard图分析揭示了单一类型的高亲和力结合位点，表观解离常数约为2.6 × 10（-10）M，每个细胞存在约1200个结合位点。125 I-IL 1与EL-4细胞的结合速率很慢，在4 ℃下需要超过3小时才能达到表观稳定状态。在去除未结合的125 I-IL 1并在存在或不存在未标记的IL 1的情况下于4 ℃孵育细胞后，细胞结合的125 I-IL 1不能从EL-4细胞解离。未标记的重组鼠IL 1以剂量依赖性方式竞争125 I-IL 1结合，而干扰素-α A、白细胞介素2（IL 2）、表皮生长因子和神经生长因子则无影响。~（125）I-IL-1结合位点对胰蛋白酶敏感，表明其定位于细胞表面。我们还研究了纯化的重组人IL 1 α和IL 1 β竞争放射性标记的鼠IL 1与其受体的结合以及刺激EL-4细胞产生IL 2的能力。先前的报道已经表明，人IL 1 α与鼠IL 1在氨基酸序列上大约60%同源，但人IL 1 β与鼠IL 1或人IL 1 α仅约25%同源。尽管这些显着的差异，但是，我们在这里报告，这两个人IL 1蛋白能够识别相同的结合位点作为小鼠IL 1。此外，鼠以及两种人IL 1蛋白刺激EL-4细胞产生IL 2。
Pure, E. coli-derived recombinant murine interleukin 1 alpha (IL 1 alpha) was labeled with 125I and used for receptor binding studies. The 125I-IL 1 binds to murine EL-4 thymoma cells in a specific and saturable manner. Scatchard plot analysis for binding studies carried out at 4 degrees C reveals a single type of high affinity binding site with an apparent dissociation constant of approximately 2.6 X 10(-10) M and the presence of approximately 1200 binding sites per cell. The rate of association of the 125I-IL 1 with EL-4 cells is slow, requiring more than 3 h to reach apparent steady state at 4 degrees C. Cell-bound 125I-IL 1 cannot be dissociated from EL-4 cells upon removal of unbound 125I-IL 1 and incubation of the cells at 4 degrees C in the presence or absence of unlabeled IL 1. Unlabeled recombinant murine IL 1 competes for 125I-IL 1 binding in a dose-dependent manner, whereas interferon-alpha A, interleukin 2 (IL 2), epidermal growth factor, and nerve growth factor have no effect. The 125I-IL 1 binding site is sensitive to trypsin, suggesting that it is localized on the cell surface. We have also examined the ability of purified recombinant human IL 1 alpha and IL 1 beta to compete for binding of the radiolabeled murine IL 1 to its receptor and to stimulate IL 2 production by EL-4 cells. Previous reports have shown that human IL 1 alpha is approximately 60% homologous in amino acid sequence with murine IL 1, but that human IL 1 beta is only about 25% homologous with either murine IL 1 or human IL 1 alpha. Despite these marked differences, however, we report here that both human IL 1 proteins are able to recognize the same binding site as mouse IL 1. In addition, murine as well as both human IL 1 proteins stimulate IL 2 production by EL-4 cells.