Binding of cyclosporine by human lymphocytes and phospholipid vesicles.
Binding of cyclosporine by human lymphocytes and phospholipid vesicles.
复制标题
环孢菌素与人淋巴细胞和磷脂囊泡的结合。
DOI：
10.4049/jimmunol.131.2.712
复制
发表时间：
1983
影响因子：
4.4
通讯作者：
B. Kahan
中科院分区：
文献类型：
--
作者：
S. Legrue;A. Friedman;B. Kahan
本研究的目的是确定和表征一个可能的质膜受体环孢素（CsA）对人类淋巴细胞。用5 × 10（-7）至10（-10）M的配体浓度检测正常人淋巴细胞和纯化淋巴细胞亚群与3 H-CsA的结合。使用500倍过量的未标记药物测定专属性。用笛卡尔或半对数分析法观察到B细胞或T细胞对~ 3 H-CsA的摄取无差异。正常外周血淋巴细胞对CsA特异性结合的Scatchard分析得出两个解离常数：高亲和力位点的KD为2 ~ 6 × 10 ~（-9）M，低亲和力位点的KD约为10 ~（-7）M CsA。纯化脾T细胞和B细胞特异性CsA摄取的Scatchard分析显示，两个群体均显示出低亲和力位点（KD分别为3至6 × 10 - 7 M和5至8 × 10 - 7 M），而只有B细胞具有高亲和力位点（KD = 2 × 10 - 9 M）。对培养的人肾细胞和磷脂囊泡（磷脂酰胆碱：胆固醇摩尔比为1：1）的特异性CsA摄取的分析表明，这两种靶点均显示出单一的低亲和力结合位点（KD分别为1 × 10 - 7 M和2 × 10 - 8 M）。低亲和力位点与CsA介导的体外免疫抑制的相关性由在混合淋巴细胞培养期间需要10（-7）M CsA来实现50%的淋巴细胞增殖抑制来提出。总之，这些数据反对在人类T细胞表面上存在特异性CsA受体。虽然不能排除某些类型的CsA诱导的免疫调节中的高亲和力B细胞受体的作用，本研究表明，免疫抑制是通过将疏水性CsA分子分配到膜脂质双层中，从而扰乱膜功能的稳态控制来实现的。
The purpose of this investigation was to identify and characterize a possible plasma membrane receptor for cyclosporine (CsA) on human lymphoid cells. Binding of 3H-CsA by normal human lymphocytes and purified lymphoid subpopulations was examined using ligand concentrations ranging from 5 X 10(-7) to 10(-10) M. Specificity was determined using a 500-fold excess of unlabeled drug. No differences were observed in the uptake of 3H-CsA by B cells or T cells using Cartesian or semilogarithmic analyses. Scatchard analysis of the specific binding of CsA by normal peripheral blood lymphocytes yielded two dissociation constants: a high affinity site with a KD of 2 to 6 X 10(-9) M and a low affinity site with a KD of about 10(-7) M CsA. Scatchard analysis of specific CsA uptake by purified splenic T cells and B cells showed both populations to exhibit a low affinity site (KD = 3 to 6 X 10(-7) M and 5 to 8 X 10(-7) M, respectively), whereas only B cells bore a high affinity site (KD = 2 X 10(-9) M). Analysis of specific CsA uptake by cultured human kidney cells and phospholipid vesicles (1:1 molar ratio of phosphatidylcholine:cholesterol) showed both these targets to display a single, low affinity binding site (KD = 1 X 10(-7) M and 2 X 10(-8) M, respectively). The relevance of the low affinity site to CsA-mediated in vitro immunosuppression was suggested by the need for 10(-7) M CsA to achieve 50% suppression of lymphoproliferation during mixed lymphocyte culture. Taken together, these data argue against the existence of a specific CsA receptor on the surface of human T cells. Although a role for the high affinity B cell receptor in some types of CsA-induced immunomodulation cannot be excluded, the present study suggests that immunosuppression is achieved by the partitioning of the hydrophobic CsA molecule into the membrane lipid bilayer, thereby perturbing homeostatic control of membrane function.