An immunosuppressant is any endogenous or exogenous molecule that inhibits normal immune system response. They generally function by inhibiting production of white blood cells. Immunosuppressants can be useful in coercing the body to accept a transplanted organ.
Cyclosporin B is a minor analogue of the cyclosporin complex produced by a number of different fungal genera including Trichoderma, Tolypocladium, Fusarium, Nectria and Acremonium. Cyclosporin B possesses immunosuppressant and antifungal activities but has been much less extensively investigated than the major analogue, cyclosporin A.
Zotarolimus is a semi-synthetic macrocyclic lactone prepared from rapamycin by preparation of the 42-triflate ester, followed by displacement with tetrazole and purification of the two isomeric products.