Research Area: Immunology Biological Activity: Cyclosporine (Neoral) is an immunosuppressant drug widely used in post-allogeneic organ transplant to reduce the activity of the patient’s immune system, and therefore the risk of organ rejection. Cyclosporine is thought to bind to the cytosolic protein cyclophilin (immunophilin) of immunocompetent lymphocytes, especially T-lymphocytes. This complex of cyclosporine and cyclophilin inhibits calcineurin, which, under normal circumstances, is responsible for activating the transcription of interleukin 2.