Batiuk T D, Pazderka F, Enns J, DeCastro L, Halloran P F
Department of Medicine, University of Alberta, Edmonton, Canada.
J Clin Invest. 1995 Sep;96(3):1254-60. doi: 10.1172/JCI118159.
Despite increasing information about the mechanism of action of cyclosporine A (CsA), little is known about the way lymphocytes recover from CsA. Recovery is central to understanding the pharmacodynamics of CsA in vivo. We studied the recovery of calcineurin phosphatase (CN) activity in CsA-treated cells. Single dose kinetics in renal transplant patients showed that inhibition of CN activity in PBL increased and fell concomitant with CsA blood vessels. In vitro, control PBL treated with CsA 100 micrograms/l, washed, and resuspended in CsA-free medium showed little recovery (0-20%) after 24 h. Erythrocytes or anti-CsA Ab added to the recovery medium increased recovery to 50% within 4 h. Similar recovery was seen in the ability of cells to produce IFN-gamma after OKT3 stimulation. Recovery of CN activity was associated with the efflux of [3H]CsA, was not blocked by cycloheximide and was temperature sensitive. A cell line with high expression of surface P glycoprotein (PGP), showed rapid recovery. However, PGP blockade did not prevent recovery in PBL, indicating a different PGP-independent mechanism. In PBL, recovery from CsA is slow and limited in vitro, but rapid in vivo, where CsA equilibrates among a complex set of extralymphocytic binding sites.
尽管关于环孢素A（CsA）作用机制的信息越来越多，但对于淋巴细胞从CsA作用中恢复的方式却知之甚少。恢复情况对于理解CsA在体内的药效学至关重要。我们研究了经CsA处理的细胞中钙调神经磷酸酶（CN）活性的恢复情况。肾移植患者的单剂量动力学研究表明，外周血淋巴细胞（PBL）中CN活性的抑制随着CsA血药浓度的升高而增强，并与之同步下降。在体外，用100微克/升的CsA处理对照PBL，洗涤后重悬于无CsA的培养基中，24小时后几乎没有恢复（0 - 20%）。向恢复培养基中加入红细胞或抗CsA抗体可使4小时内的恢复率提高到50%。在OKT3刺激后细胞产生γ干扰素的能力方面也观察到类似的恢复情况。CN活性的恢复与[3H]CsA的流出相关，不受放线菌酮的阻断，且对温度敏感。一种表面P糖蛋白（PGP）高表达的细胞系显示出快速恢复。然而，PGP阻断并不能阻止PBL的恢复，这表明存在一种不同的不依赖PGP的机制。在PBL中，体外从CsA作用中的恢复缓慢且有限，但在体内则很快，在体内CsA会在一系列复杂的淋巴细胞外结合位点之间达到平衡。
