The long term goal of this investigation is to establish the potential value of active or passive immunization with anticocaine catalytic antibodies as a therapeutic approach to the acute or chronic treatment of cocaine abuse. The specific objectives of the current proposal are to establish a preclinical animal model capable of producing anti-cocaine catalytic antibodies with high levels of esterase activity and to examine the magnitude of the impact of these antibodies on bioavailability of acutely administered cocaine as measured by changes in cocaine catabolism, biodistribution and behavioral actions. These effects will be examined in both actively and passively immunized animals. Our newly synthesized Transition State Analogs (TSA) of cocaine, TSA-I to TSA-IV, will be used as haptens attached to Diphtheria Toxoid (DT) to immunize mice (C57BL/6J) to produce catalytic antibodies with the ability to hydrolyze cocaine to the inactive metabolites, ecgonine methyl ester and benzoic acid. Eight TSAs conjugated to DT will be evaluated for their relative ability to produce such catalytic antibodies. The three TSA-DT conjugates producing the highest total activity and/or specific activity of catalytic antibodies will be evaluated in detail for their ability to reduce cocaine's entry into the brain to elicit its behavioral effects. The ability of this immunization to reduce cocaine's behavioral potency and/or efficacy will be evaluated using four endpoints: conditioned place preference, locomotor activity stimulation, seizure induction and lethality. Changes in metabolism and distribution of cocaine following this immunization will be evaluated and related to the amount of catalytic antibody activity and to any observed changes in the behavioral action of cocaine. Finally, the protective effect of passive immunization with affinity purified polyclonal antibodies isolated from sera of actively immunized mice will be assessed in the same manner at various times after passive immunization. This systematic behavioral, pharmacokinetic and immunological characterization of the efficacy of active and passive immunization against cocaine with the novel cocaine TSA-conjugates will identify in a murine model the potential benefit and pitfalls of this approach. This information is necessary prior to initiation of such studies in humans.
