Low J E, Jardine I
J Pharmacol Exp Ther. 1986 Jul;238(1):39-45.
The binding of [3H]cyclosporine A (CsA) to BALB/c mouse spleen cells was examined with a novel centrifugation assay which rapidly removes free [3H]CsA from cell surfaces with a minimal loss of low affinity specifically bound [3H]CsA. A single class of specific and saturable CsA binding sites was found under equilibrium binding conditions. Scatchard analysis of the data resulted in a straight line with KD and Bmax values of 95 nM and 2.4 million binding sites/cell, respectively. Kinetic studies conducted with a wider range of [3H]CsA concentrations revealed two distinct binding sites, with KD's of 290 nM and 9.6 microM, respectively. [3H]CsA bound only nonspecifically to phosphatidylcholine:cholesterol liposomes. Specific [3H]CsA binding sites were found in murine WEHI-5 B-lymphoma cells, murine N1E-115 neuroblastoma cells and human A204 rhabdosarcoma cells. We conclude from these results that there are at least two nonlipid CsA binding sites in BALB/c mouse spleen cells and that CsA binding sites are present in both lymphoid and nonlymphoid tissue.
采用一种新型离心测定法检测了[3H]环孢素A（CsA）与BALB/c小鼠脾细胞的结合情况，该方法能快速从细胞表面去除游离的[3H]CsA，同时使低亲和力特异性结合的[3H]CsA损失最小。在平衡结合条件下发现了一类单一的特异性且可饱和的CsA结合位点。对数据进行Scatchard分析得到一条直线，KD和Bmax值分别为95 nM和240万个结合位点/细胞。用更广泛的[3H]CsA浓度进行的动力学研究揭示了两个不同的结合位点，KD分别为290 nM和9.6 μM。[3H]CsA仅非特异性地结合于磷脂酰胆碱：胆固醇脂质体。在小鼠WEHI-5 B淋巴瘤细胞、小鼠N1E-115神经母细胞瘤细胞和人A204横纹肌肉瘤细胞中发现了特异性[3H]CsA结合位点。从这些结果我们得出结论，BALB/c小鼠脾细胞中至少有两个非脂质CsA结合位点，且CsA结合位点存在于淋巴组织和非淋巴组织中。
