Isoprenoid formation and cell-mediated immunological functions.

Isoprenoid molecules are formed through a complex, multi-enzyme synthetic pathway. Main products of this pathway are cholesterol, bile acid and steroids. In addition, there are minor products of the pathway, such as dolichol, isopentenyl adenosine and ubiquinone. The early rate limiting step in all isoprenoid synthesis is the formation of mevalonate catalyzed by 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase. Potent and specific competitive inhibitors of HMG-CoA reductase have been identified, which can block mevalonate formation and reduce cholesterol and other isoprenoid production. For example, mevinolin and several of its derivatives are increasingly being used clinically for treatment of hypercholesterolemia, particularly with view to improvement of cardiovascular disease (1,2,3).