Safety and efficiency of an anti-(+)-methamphetamine monoclonal antibody in the protection against cardiovascular and central nervous system effects of (+)-methamphetamine in rats
ABSTRACT The purpose of these studies was to determine if a high-affinity, anti-(+)-methamphetamine (METH) monoclonal antibody (mAb6H4; KD=11 nM) protects against METH-induced central nervous and cardiovascular system effects in rats. Rats (n=5 per group) received one of three anti-METH mAb6H4 doses, equal to 0.32, 0.56 or 1 times the mole equivalent (mol-eq) amount of METH in the body following a 1 mg/kg i.v. METH dose. Each rat was challenged with METH (1 mg/kg, i.v.) 1 and 4 days after the anti-METH mAb dose. The 1 mol-eq anti-METH mAb dose significantly reduced the duration of METH-induced locomotor activity (horizontal locomotion and rearing events), heart rate and blood pressure effects from 2 to 3 h to about an hour. This resulted in a significant reduction in total locomotor activity and the area under the hemodynamic effect vs. time curve for heart rate and blood pressure. In addition, the time to peak locomotor activity was decreased after the 1 mol-eq mAb dose vs. the lower doses. These changes were limited to the first METH challenge. The responses to the second METH challenge were not different from baseline. The peak hemodynamic and locomotor activity values were unchanged after both challenges. These results indicate anti-METH mAb6H4 can safely reduce the hemodynamic and locomotor effects of METH given one day after anti-METH IgG, and that the mAb is safe when administered in the absence of METH. These results are important because they indicate these antibody medications have simultaneous beneficial effects in multiple organ systems.
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- "In pursuit of effective treatments for METH abuse, that could be used in conjunction with behavioral therapies, anti-METH monoclonal antibodies (mAbs) have been developed45. The first generation mAbs have been well characterized in vivo and in vitro678 and have shown significant preclinical efficacy. In METH abuse rodent models, anti-METH mAbs significantly reduce METH brain concentrations and relapse to METH self-administration and shorten the duration of METH-induced locomotor activity91011. "
ABSTRACT: Methamphetamine (METH) abuse is a worldwide threat, without any FDA approved medications. Anti-METH IgGs and single chain fragments (scFvs) have shown efficacy in preclinical studies. Here we report affinity enhancement of an anti-METH scFv for METH and its active metabolite amphetamine (AMP), through the introduction of point mutations, rationally designed to optimize the shape and hydrophobicity of the antibody binding pocket. The binding affinity was measured using saturation binding technique. The mutant scFv-S93T showed 3.1 fold enhancement in affinity for METH and 26 fold for AMP. The scFv-I37M and scFv-Y34M mutants showed enhancement of 94, and 8 fold for AMP, respectively. Structural analysis of scFv-S93T:METH revealed that the substitution of Ser residue by Thr caused the expulsion of a water molecule from the cavity, creating a more hydrophobic environment for the binding that dramatically increases the affinities for METH and AMP.Scientific Reports 01/2014; 4:3673. DOI:10.1038/srep03673 · 5.58 Impact Factor
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- "Acute MA exposure resulted in a sustained and significant increase in RR (Fig. 1D), in agreement with previous reports (Gentry et al., 2006;Mendelson et al., 2006;Richards et al., 1995). Elevated RR can lead to hypocapnia, manifested as a reduced arterial partial pressure of CO 2 (PaCO 2 ). "
ABSTRACT: The use prevalence of the highly addictive psychostimulant methamphetamine (MA) has been steadily increasing over the past decade. MA abuse has been associated with both transient and permanent alterations in cerebral blood flow (CBF), hemorrhage, cerebrovascular accidents and death. To understand MA-induced changes in CBF, we exposed C56BL/6 mice to an acute bolus of MA (5mg/kg MA, delivered IP). This elicited a biphasic CBF response, characterized by an initial transient increase (~ 5 minutes) followed by a prolonged decrease (~ 30 minutes) of approximately 25% relative to baseline CBF--as measured by laser Doppler flowmetry over the somatosensory cortex. To assess if this was due to catecholamine derived vasoconstriction, phentolamine, an α-adrenergic antagonist was administered prior to MA treatment. This reduced the initial increase in CBF but failed to prevent the subsequent, sustained decrease in CBF. Consistent with prior reports, MA caused a transient increase in mean arterial blood pressure, body temperature and respiratory rate. Elevated respiratory rate resulted in hypocapnia. When respiratory rate was controlled by artificially ventilating mice, blood PaCO(2) levels after MA exposure remained unchanged from physiologic levels, and the MA-induced decrease in CBF was abolished. In vivo two-photon imaging of cerebral blood vessels revealed sustained MA-induced vasoconstriction of pial arterioles, consistent with laser Doppler flowmetry data. These findings show that even a single, acute exposure to MA can result in profound changes in CBF, with potentially deleterious consequences for brain function.Brain research 02/2011; 1373:91-100. DOI:10.1016/j.brainres.2010.12.017 · 2.83 Impact Factor
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- "Earlier reports have described the generation of mAb against (+)METH for diagnostic use (Faraj et al., 1976; Usagawa et al., 1989; Suttijitpaisal and Ratanabanangkoon, 1992), but none have reported the high affinity and class specificity that would be required to make a broadly effective antagonist for (+)METH-like drugs. Our group (McMillan et al., 2002; Laurenzana et al., 2003; Byrnes-Blake et al., 2005; Gentry et al., 2006; Pitas et al., 2006) and others (Danger et al., 2006) have reported the generation of potential mAb antagonist for (+)METH, or (±)METH as a racemic mixture (Danger et al., 2006). Our laboratory has also reported that some of these anti-(+)METH mAb medications are effective for treating METH overdose (Byrnes-Blake et al., 2005) and for blocking (+)METH self-administration (McMillan et al., 2004) in rat models of human drug use. "
ABSTRACT: 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 (+)-methamphetamine [(+)-METH], (+)-amphetamine [(+)-AMP], and the related compound (+)-3,4-methylenedioxymethamphetamine [(+)-MDMA, the plus isomer in the racemic mixture known as MDMA or ecstasy]. The goal of these studies was to design and synthesize (+)-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 (+)-METH-like haptens, which mimic structural aspects of these drugs, were synthesized and used to generate mAb. After screening for anti-(+)-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 IgG-variable 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 (+)-METH and (+)-MDMA; whereas one antibody (designated mAb4G9) exhibited high affinity and specificity to (+)-METH, (+)-MDMA, and (+)-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.Journal of Pharmacology and Experimental Therapeutics 08/2007; 322(1):30-9. DOI:10.1124/jpet.106.117150 · 3.86 Impact Factor