rIL-2的^(125)Ⅰ标记及淋巴细胞IL-2受体的鉴定

Radioiodination of rIL-2 and identification of IL-2 receptor on lymphocytes

为测定白细胞介素-2受体(IL-2R)的表达水平,应用 lodogen 法对重组 IL-2(rlL-2)进行^(125)I 标记,以放射配基结合分析法对大鼠脾淋巴细胞表面 IL-2R 进行鉴定。结果表明,rlL-2蛋白质标记率为58.8%,比活度为488.4kBq/μg;^(125)I-IL-2在10～150pmol/L 范围内与淋巴细胞 IL-2R 呈特异性结合,为可饱和的双分子过程,最大结合容量和平衡解离常数分别为10.00±0.68fmol/10~7细胞和73.84±21.06pmol/L。动力学实验表明配基与细胞特异结合具有可逆性,提示可用标记配基对淋巴细胞高亲和力 IL-2R 进行鉴定。

PURPOSE To establish a technique for the identification of high affinity IL-2 receptors on lymphocytes.METH- ODS rIL-2 was radioiodinated with Na^(125)Ⅰ by means of Iodogen method and IL-2 receptor was detected by radioligand binding assay.RESULTS The labelling rate of rIL-2 was 58.8% and the specific radioactivity of ^(125)I-rlL-2 was 488.4kBq/μg.^(125)-rIL- 2 ranging from 10 to 150pmol/L mainly bound to high affinity rIL-2 receptor.The maximal binding capacity (B_(max)) and the equi- librium dissociation constant (Kd) were 10.00±0.68fmol./10~7 cells and 73.84±21.06pmol/L respectively.Evidences are provid- ed to demonstrate that the binding is saturable and reversible.CONCLUSIONS ^(125)I-rIL-2 can be used as radioligand to identify the high affinity rIL-2 receptor on lymphocytes.