Figure 1.

Mechanism of action of a vaccine against cocaine addiction. In the absence of the vaccine, cocaine is readily absorbed at the blood–brain barrier and thereby enters the brain. As shown in the top part of this figure, the vaccine interacts with dendritic blood cells to produce antibodies from B-cells that are secreted into the blood stream. In the brain, the drug causes reinforcement of pleasurable effects, or the ‘high’ associated with cocaine. If a vaccine is administered, it stimulates the production of antibodies against cocaine. Subsequently, if cocaine is taken, the antibodies bind to the drug and sequester it in the blood circulation. This antibody–drug binding prevents the cocaine from rapidly leaving the blood vessels and entering the brain, thereby reducing the drug's euphoric effects