Freed B M, Rosano T G, Lempert N
Transplantation. 1987 Jan;43(1):123-7. doi: 10.1097/00007890-198701000-00027.
The in vitro biological activity of cyclosporine (CsA) and four of its metabolites (M1, M8, M17, and M21) was determined. M1, M17, and M21 are primary metabolites, while M8 is a secondary metabolite derived from either M1 or M17. The order of inhibitory activity in production assays was phytohemagglutinin (PHA), concanavalin A (ConA), mixed lymphocyte culture (MLC), and interleukin-2 (IL-2) CsA greater than M17 greater than M1 greater than M21 much greater than M8. In the PHA assay, CsA was significantly more inhibitory than M17, but in Con A and MLC assays, the inhibitory activity of M17 approached that of CsA. More importantly, M17 and M1 inhibited the production of IL-2 in the MLC to the same extent as CsA. M21 was significantly less inhibitory than either M17 or M1, and M8 appeared to be largely devoid of biological activity. These experiments demonstrate that single hydroxylations of amino acids 1 (M17) and 9 (M1) do not significantly affect the ability of the molecule to block IL-2 production, but hydroxylation of both amino acids renders the molecule virtually inactive. In addition, the presence of the N-methyl group on amino acid 4 appears to be very important, since removal of this group (M21) greatly diminishes the immunosuppressive activity.
测定了环孢素（CsA）及其四种代谢物（M1、M8、M17和M21）的体外生物活性。M1、M17和M21是主要代谢物，而M8是源自M1或M17的次要代谢物。在生产试验中，抑制活性顺序为：植物血凝素（PHA）、刀豆蛋白A（ConA）、混合淋巴细胞培养（MLC）和白细胞介素-2（IL-2），CsA＞M17＞M1＞M21＞＞M8。在PHA试验中，CsA的抑制作用明显强于M17，但在ConA和MLC试验中，M17的抑制活性接近CsA。更重要的是，M17和M1在MLC中对IL-2产生的抑制程度与CsA相同。M21的抑制作用明显弱于M17或M1，M8似乎基本没有生物活性。这些实验表明，氨基酸1（M17）和9（M1）的单羟基化不会显著影响分子阻断IL-2产生的能力，但两个氨基酸的羟基化会使分子几乎失活。此外，氨基酸4上N-甲基的存在似乎非常重要，因为去除该基团（M21）会大大降低免疫抑制活性。
