Final answer:
Cyclosporine is an immunosuppressant drug used to prevent organ transplant rejection by inhibiting interleukin-2 production and T-cell activation.
Step-by-step explanation:
The drug cyclosporine plays a critical role in the field of organ transplantation. As an immunosuppressant, cyclosporine works by inhibiting the production of interleukin-2, a key cytokine involved in T-cell activation and proliferation, thereby suppressing the immune system's rejection of transplanted organs. This mechanism of action makes cyclosporine an essential medication for patients who have undergone organ transplants to prevent their immune system from attacking the newly transplanted tissue.