Pharmaceutical companies, such as Lundbeck, are currently exploring the use of transcytosis as a mechanism for transporting therapeutic drugs across the human blood–brain barrier (BBB).[citation needed] Exploiting the body's own transport mechanism can help to overcome the high selectivity of the BBB, which typically blocks the uptake of most therapeutic antibodies into the brain and central nervous system (CNS). The pharmaceutical company Genentech, after having synthesized a therapeutic antibody that effectively inhibited BACE1 enzymatic function, experienced problems transferring adequate, efficient levels of the antibody within the brain.