The immunosuppressant action of cyclosporine appears to be due to:: (A) Activation of NK cells, (B) Blockade of tissue responses to inflammatory mediators, (C) Inhibition of gene transcription of interleukins, (D) Interference with antigen recognition
Answer is C. (Ref: KDT 6/e p838, 839,840) Cyclosporine and tacrolimus acts by inhibiting calcineurin, which is involved in the activation of NFAT. Final result of this process is increased transcription of IL-2 gene. Sirolimus does not inhibit the transcription of IL-2 but interferes with its action. It inhibits the enzyme tyrosine kinase, known as mTOR (which is activated byIL-2)