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When generating monoclonal antibodies (mAb) against small molecules, the chemical composition and molecular orientation of the drug-like hapten on the antigen is a crucial determinant. This is especially important when attempting to discover therapeutic mAb against the drugs of abuse (ϩ)-methamphetamine, and the related compound (ϩ)-3,4-methylenedioxymethamphetamine [(ϩ)-MDMA, the plus isomer in the racemic mixture known as MDMA or ecstasy]. The goal of these studies was to design and synthesize (ϩ)-METH-like haptens with structural attributes that could make them effective for generating monoclonal antibodies for treating medical problems associated with these stimulant drugs of abuse. Five prototype (ϩ)-METH-like haptens, which mimic structural aspects of these drugs, were synthesized and used to generate mAb. After screening for anti-(ϩ)-METH IgG antibodies in more than 25,000 potential mouse hybridoma cell lines, one prototype mAb from each of the five haptens was selected and studied in detail for molecular properties and preclinical efficacy. The amino acid sequences of the IgGvariable regions, structural models, affinity, and ligand specificity of each mAb were then used to help elucidate important therapeutic characteristics. Four of these antibodies exhibited high affinity and specificity to (ϩ)-METH and (ϩ)-MDMA; whereas one antibody (designated mAb4G9) exhibited high affinity and specificity to (ϩ)-METH, (ϩ)-MDMA, and (ϩ)-AMP, without significant cross-reactivity against other METH-like ligands, over-the-counter medications, or endogenous neurotransmitters. Considered together, discovery of mAb4G9 and the other antibodies in this report represent an important step in understanding the process for custom design of drug class-specific therapeutic antibodies for the treatment of drug addiction. (ϩ)-Methamphetamine [(ϩ)-METH] abuse has becomeAmerica's number one drug threat (NACo, 2005), and effective treatment strategies for abuse of (ϩ)-METH and related stimulants are greatly needed. Current pharmacotherapies for managing the acute cardiovascular system, central nervous system, and toxic effects are mostly supportive (Sato, 1992;Albertson et al., 1999;Richards et al., 1999); they do nothing to remove the drug from its sites of action in the brain. Also lacking are medications that can reduce or treat the medically crippling effects of (ϩ)-METH addiction. Monoclonal antibodies (mAb) provide an attractive potential medication that can target the drug instead of the site of action (Kosten and Owens, 2005). These high-affinity protein-based medications act as so-called pharmacokinetic antagonists, sequestering the drug in the bloodstream away from medically vulnerable tissues, such as the brain and heart. Unlike nicotine and cocaine where the effects are caused by a single, specific compound, drugs such as opiates (e.g., morphine), arylcyclohexylamines (e.g., phencyclidine) and amphetamines [e.g., (ϩ)-METH] are starting structures from which many pharmacologically similar compounds can be synthesize...

No abstract

Our results demonstrate that both synthetic activity in VTA neurons and the responsiveness of accumbens DA neurons is altered by maternal nutrition. These effects subside long after termination of exposure to the HF diet.

Chronic or excessive (ϩ)-methamphetamine (METH) use often leads to addiction and toxicity to critical organs like the brain. With medical treatment as a goal, a novel single-chain variable fragment (scFv) against METH was engineered from anti-METH monoclonal antibody mAb6H4 (IgG, light chain, K d ϭ 11 nM) and found to have similar ligand affinity (K d ϭ 10 nM) and specificity as mAb6H4. The anti-METH scFv (scFv6H4) was cloned, expressed in yeast, purified, and formulated as a naturally occurring mixture of monomer (ϳ75%) and dimer (ϳ25%). To test the in vivo efficacy of the scFv6H4, male Sprague-Dawley rats (n ϭ 5) were implanted with 3-day s.c. osmotic pumps delivering 3.2 mg/kg/day METH. After reaching steady-state METH concentrations, an i.v. dose of scFv6H4 (36.5 mg/kg, equimolar to the METH body burden) was administered along with a [ 3 H]scFv6H4 tracer. Serum pharmacokinetic analysis of METH and [3 H]scFv6H4 showed that the scFv6H4 caused an immediate 65-fold increase in the METH concentrations and a 12-fold increase in the serum METH area under the concentration-time curve from 0 to 480 min after scFv6H4 administration. The scFv6H4 monomer was quickly cleared or converted to multivalent forms with an apparent t 1/2z of 5.8 min. In contrast, the larger scFv6H4 multivalent forms (dimers, trimers, etc.) showed a much longer t 1/2z (228 min), and the significantly increased METH serum molar concentrations correlated directly with scFv6H4 serum molar concentrations. Considered together, these data suggested that the scFv6H4 multimers (and not the monomer) were responsible for the prolonged redistribution of METH into the serum.There are currently nearly 20 monoclonal antibody (mAb) medications approved by the United States Food and Drug Administration and over 20 more in early clinical or preclinical trials (Holliger and Hudson, 2005). These medications include full-length IgG mAbs, along with five mAb fragments as Fab, F(abЈ) 2 (antigen binding fragments of IgG), or singlechain variable fragment (scFv) proteins.IgG mAbs are typically chimeric, humanized, or fully human proteins and are administered to patients requiring a long-acting antagonist with minimal extravascular penetration (Bazin-Redureau et al., 1997). IgG mAb is best for this purpose because it has a terminal elimination half-life (t 1/2z ) ranging from approximately 3 to 26 days. The longest t 1/2z values are usually achieved when the antibody does not bind to tissue sites and is not prematurely cleared due to antigenicity. When a short duration of action and greater extravascular penetration are needed, a significantly smaller fragment like Fab (t 1/2z ranging from 0.5-21 h; Trang, 1992) or scFv (t 1/2z ranging from minutes to hours; Goel et al., 2000) is used. In particular, rat pharmacokinetic studies of an antianthrax toxin scFv report a t 1/2␣ of ϳ5 min (Maynard et al., 2002). In addition, PCKN studies of a scFv in mice report t 1/2␣ values of 2.7 and 1 min Willuda et al., 2001). It is possible that a short-acting scFv could be used to