Cyclosporin A is an immunosuppressive agent, that binds to the cyclophilin and then inhibits calcineurin with IC₅₀ of 7 nM in a cell-free assay, and is widely used in organ transplantation to prevent rejection.

IC50: 7 nM (calcineurin)

Cyclosporin A binds to the cyclophilin (immunophilin) in T cells^[1], and forms a Cyclophilin-Cyclosporin A complex which inhibits calcineurin^[2]. Cyclosporin A inhibits calcineurin with IC₅₀ of 7 nM^[3], then blocks the nuclear translocation of NF-AT^[4]. Cyclosporin A also affects mitochondria by preventing the MTP (mitochondrial permeability transition pore) from opening with an IC₅₀ of 39 nM^[5]. 

Cyclosporin A is an immunosuppressive agent that is effective following either parenteral or oral administration in mice, rat and guinea pigs^[6]. Cyclosporin A is clinically used in organ transplantation to prevent rejection^[7]. 

• [1]. Handschumacher RE, et al. Cyclophilin: a specific cytosolic binding protein for cyclosporin A. Science. 1984 Nov 2;226(4674):544-7.

  [2]. Liu J, et al. Calcineurin is a common target of cyclophilin-cyclosporin A and FKBP-FK506 complexes. Cell. 1991 Aug 23;66(4):807-15.

  [3]. Fruman DA, et al. Calcineurin phosphatase activity in T lymphocytes is inhibited by FK 506 and cyclosporin A. Proc Natl Acad Sci U S A. 1992 May 1;89(9):3686-90.

  [4]. Flanagan WM, et al. Nuclear association of a T-cell transcription factor blocked by FK-506 and cyclosporin A. Nature. 1991 Aug 29;352(6338):803-7.

  [5]. Nicolli A, et al. Interactions of cyclophilin with the mitochondrial inner membrane and regulation of the permeability transition pore, and cyclosporin A-sensitive channel. J Biol Chem. 1996 Jan 26;271(4):2185-92.

  [6]. Borel JF, et al. Effects of the new anti-lymphocytic peptide cyclosporin A in animals. Immunology. 1977 Jun;32(6):1017-25.

  [7]. Williams, R, et al. Randomised trial comparing tacrolimus (FK506) and cyclosporin in prevention of liver allograft rejection. European FK506 Multicentre Liver Study Group. Lancet, 1994, 344(8920), 423-428.

Reaction mixtures with purified enzyme contains 100 nM calcineurin, 100 nM calmodulin, and 5 μM ³²P-labeled phosphopeptide, in 60 μL (total volume) of assay buffer containing 20 mM Tris (pH 8), 100 mM NaCl, 6 mM MgCl₂, 0.5 mM dithiothreitol, 0.1 mg of bovine serum albumin per mL, and either 0.1 mM CaCl₂ or 5 mM EGTA. Reaction mixtures with cell lysates contains 20 μL of undiluted lysate, 5 μM ³²P-labeled phosphopeptide, and 40 μL of assay buffer. Reaction mixtures contains 50 μM peptide 412 or 413 and/or 500 nM okadaic acid, a specific inhibitor of phosphatases 1 and 2A; 500 nM okadaic acid is sufficient for inhibition of Ca²⁺-independent phosphatases, whereas higher concentrations partially inhibit Ca²⁺-dependent activity as well. After 15 min at 30°C, reactions are terminated by the addition of 0.5 mL of 100 mM potassium phosphate buffer (pH 7.0) containing 5% trichloroacetic acid. Free inorganic phosphate is isolated by Dowex cation-exchange chromatography and quantitated by scintillation counting as described. MCE has not independently confirmed the accuracy of these methods. They are for reference only.

Cyclosporin A is dissolved in ethanol.

Immunosuppressive agents are dissolved in ethanol at concentrations 1000-fold more than the concentration desired for cell treatments. Cells (10⁶) are suspended in 1 mL of complete medium in microcentrifuge tubes; 1 μL of ethanol or of the ethanolic solution of Cyclosporin A is added, and the cells are incubated at 37°C for 1 hr. Cells are washed twice with 1 mL of PBS on ice and lysed in 50 μL of hypotonic buffer containing 50 mM Tris (pH 7.5); 0.1 mM EGTA; 1 mM EDTA; 0.5 mM dithiothreitol; and 50 μg of phenylmethylsulfonyl fluoride, 50 μg of soybean trypsin inhibitor, 5 μg of leupeptin, and 5 μg of aprotinin per mL. Lysates are subjected to three cycles of freezing in liquid nitrogen followed by thawing at 30°C and then are centrifuged at 4°C for 10 min at 12,000×g. MCE has not independently confirmed the accuracy of these methods. They are for reference only.

Cyclosporin A is suspended in 0.5% solution of tragacanth.

Rats are immunized on day 0 i.p. with 0 5 mL and mice i.v. with 0 2 mL of a 10% suspension of washed sheep erythrocytes (SE). To elicit a secondary response, mice are boosted 8-11 weeks after the primary immunization with an i.v. injection of 0-2 mL of 0 25% washed SE (10⁷ cells). For prolonged treatment the animals receive on the average 45 mg/kg cyclosporin A daily in the food during 13 weeks. These rats are immunized 5 days before killing. MCE has not independently confirmed the accuracy of these methods. They are for reference only.

• [1]. Handschumacher RE, et al. Cyclophilin: a specific cytosolic binding protein for cyclosporin A. Science. 1984 Nov 2;226(4674):544-7.

  [2]. Liu J, et al. Calcineurin is a common target of cyclophilin-cyclosporin A and FKBP-FK506 complexes. Cell. 1991 Aug 23;66(4):807-15.

  [3]. Fruman DA, et al. Calcineurin phosphatase activity in T lymphocytes is inhibited by FK 506 and cyclosporin A. Proc Natl Acad Sci U S A. 1992 May 1;89(9):3686-90.

  [4]. Flanagan WM, et al. Nuclear association of a T-cell transcription factor blocked by FK-506 and cyclosporin A. Nature. 1991 Aug 29;352(6338):803-7.

  [5]. Nicolli A, et al. Interactions of cyclophilin with the mitochondrial inner membrane and regulation of the permeability transition pore, and cyclosporin A-sensitive channel. J Biol Chem. 1996 Jan 26;271(4):2185-92.

  [6]. Borel JF, et al. Effects of the new anti-lymphocytic peptide cyclosporin A in animals. Immunology. 1977 Jun;32(6):1017-25.

  [7]. Williams, R, et al. Randomised trial comparing tacrolimus (FK506) and cyclosporin in prevention of liver allograft rejection. European FK506 Multicentre Liver Study Group. Lancet, 1994, 344(8920), 423-428.

1202.61

C₆₂H₁₁₁N₁₁O₁₂

59865-13-3

Room temperature in continental US; may vary elsewhere

10 mM in DMSO

* "<1 mg/ml"="" means="" slightly="" soluble="" or="" insoluble.="" "≥"="" means="" soluble,="" but="" saturation="">