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Clinical trials have indicated that a vaccine must be immunogenic in genetically diverse human populations and that immunogenicity and protective efficacy in animal models are two key indices required for the approval of a new vaccine. Additionally, the immune response (immunogenicity) and immunoprotection are dependent on the mouse strain. Therefore, the objective of the present study was to determine the immune response (immunogenicity) and the protective efficacy (behavioral response) in three inbred mouse strains immunized with the M6TT vaccine. Female BALB/c, C57Bl/6, and DBA/2 inbred mice were immunized with the M6-TT vaccine. A solid-phase antibody-capture ELISA was used to monitor antibody titer responses after each booster dose in vaccinated animals. The study used tail-flick testing to evaluate the antinociceptive effects induced by heroin. Additionally, heroin-induced locomotor activity and place preference were evaluated. The M6-TT vaccine was able to generate a specific antibody titer in the three inbred mouse strains evaluated. The antibodies reduced the antinociceptive effect of different doses of heroin. In addition, they decreased the heroin-induced locomotor activity and place preference. These findings suggest that the M6-TT vaccine generates a powerful immunogenic response capable of reducing the antinociceptive and reinforcing effects of heroin in different inbred mouse strains, which supports its possible future use in clinical trials in genetically diverse human populations.

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Adjuvants are a diverse family of substances whose main objective is to increase the strength, quality, and duration of the immune response caused by vaccines. The most commonly used adjuvants are aluminum-based, oil-water emulsion, and bacterial-origin adjuvants. In this paper, we will discuss how the election of adjuvants is important for the adjuvant-mediated induction of immunity for different types of vaccines. Aluminum-based adjuvants are the most commonly used, the safest, and have the best efficacy, due to the triggering of a strong humoral response, albeit generating a weak induction of cell-mediated immune response. Freund's adjuvant is the most widely used oil-water emulsion adjuvant in animal trials; it stimulates inflammation and causes aggregation and precipitation of soluble protein antigens that facilitate the uptake by antigen-presenting cells (APCs). Adjuvants of bacterial origin, such as flagellin, E. coli membranes, and monophosphoryl lipid A (MLA), are known to potentiate immune responses, but their safety and risks are the main concern of their clinical use. This minireview summarizes the mechanisms that classic and novel adjuvants produce to stimulate immune responses.

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BACKGROUND: Relapse to cocaine use is a major problem in the clinical treatment of cocaine addiction. Antidepressants have been studied for their therapeutic potential to treat cocaine use disorder. Research has suggested that antidepressants attenuate both drug craving and the re-acquisition of drug-seeking and drug-taking behaviors. This study examined the efficacy of mirtazapine, an antidepressant/anxiolytic, in decreasing cocaine seeking in rats. METHODS: We used the cocaine self-administration paradigm to assess the effects of mirtazapine on rats trained to self-administer cocaine or food under a fixed-ratio schedule. Mirtazapine (30 mg/kg, i.p.) was administered during extinction. RESULTS: Mirtazapine significantly attenuated non-reinforced lever-press responses during extinction. Moreover, the mirtazapine dosed for 30 days during extinction produced sustained attenuation of lever-press responses during re-acquisition of cocaine self-administration, without changing food-seeking behavior. Our results showed that mirtazapine attenuated the re-acquisition of cocaine-seeking responses. CONCLUSION: Our study pointed to the efficacy of mirtazapine in reducing the risk of drug relapse during abstinence, suggesting for its potential use as a novel pharmacological agent to treat drug abuse.

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Cocaine abuse is a major health problem worldwide. Treatment based on both 5-HT2A/C and 5-HT3 receptor antagonists attenuate not only the effects of cocaine abuse but also the incentive/motivational effect related to cocaine-paired cues. Mirtazapine, an antagonist of postsynaptic α2-adrenergic, 5-HT2A/C and 5HT3 receptors and inverse agonist of the 5-HT2C receptor, has been shown to effectively modify, at the preclinical and clinical levels, various behavioral alterations induced by drugs abuse. Therefore, it is important to assess whether chronic dosing of mirtazapine alters locomotor effects of cocaine as well as induction and expression of cocaine sensitization. Our results reveal that a daily mirtazapine regimen administered for 30days effectively induces a significant attenuation of cocaine-dependent locomotor activity and as well as the induction and expression of behavioral sensitization. These results suggest that mirtazapine may be used as a potentially effective therapy to attenuate induction and expression of cocaine-induced locomotor sensitization.

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BACKGROUND: Alpha (α)-amidation of peptides is a mechanism required for the conversion of prohormones into functional peptide sequences that display biological activities, receptor recognition and signal transduction on target cells. Alpha (α)-amidation occurs in almost all species and amino acids identified in nature. C-terminal valine amide neuropeptides constitute the smallest group of functional peptide compounds identified in neurosecretory structures in vertebrate and invertebrate species. METHODS: The α-amidated isoform of valine residue (Val-CONH2) was conjugated to KLH-protein carrier and used to immunize mice. Hyperimmune animals displaying high titers of valine amide antisera were used to generate stable hybridoma-secreting mAbs. Three productive hybridoma (P15A4, P17C11, and P18C5) were tested against peptides antigens containing both the C-terminal α-amidated (-CONH2) and free α-carboxylic acid (-COO(-)) isovariant of the valine residue. RESULTS: P18C5 mAb displayed the highest specificity and selectivity against C-terminal valine amidated peptide antigens in different immunoassays. P18C5 mAb-immunoreactivity exhibited a wide distribution along the neuroaxis of the rat brain, particularly in brain areas that did not cross-match with the neuronal distribution of known valine amide neuropeptides (α-MSH, adrenorphin, secretin, UCN1-2). These brain regions varied in the relative amount of putative novel valine amide peptide immunoreactive material (nmol/µg protein) estimated through a fmol-sensitive solid-phase radioimmunoassay (RIA) raised for P18C5 mAb. CONCLUSIONS: Our results demonstrate the versatility of a single mAb able to differentiate between two structural subdomains of a single amino acid. This mAb offers a wide spectrum of potential applications in research and medicine, whose uses may extend from a biological reagent (used to detect valine amidated peptide substances in fluids and tissues) to a detoxifying reagent (used to neutralize exogenous toxic amide peptide compounds) or as a specific immunoreagent in immunotherapy settings (used to reduce tumor growth and tumorigenesis) among many others.

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Drug addiction is one of the most important health problems in the world. This psychiatry disease results in the death of about 500 000 individuals annually in the world. Despite this scenario, the development of effective drug therapies against this disease has been slow and not very successful. In recent years, new alternative pharmacological strategies against drug addiction have been designed and validated. Among them are vaccines against drugs like nicotine, morphine or cocaine and their subsequent use in immunotherapeutic pharmacological procedures for the treatment of addictive behaviors of drug consumption, both in animal models and in humans. These strategies are based on the experimental design and synthesis of various structural formulations of therapeutic vaccines against drugs of abuse. When dosed in active immunization schedules, they induce the production of specific antibodies, which recognize and bind these substances in the intravascular space and prevent the drug permeability through the blood brain barrier, resulting in decreased effects of drugs into the brain. In 2006, our research group at the National Institute of Psychiatry Ramón de la Fuente Muñiz (INPRFM) achieved and consolidated the design, synthesis, application and validation of immunoprotective therapeutic effects against relapse to morphine/heroin addiction in a rodent animal model, a model vaccine for potential human use against addiction to morphine/heroin. This model shows immunogenic capacities (high and sustained titers of highly specific antibodies) and immunoprotection (attenuates the effect up to 15mg/kg sc morphine) that the structural vaccine models competing have not been matched, which makes it the leading vaccine model against the addictive effects of heroin and morphine.

La adicción a una droga de abuso representa uno de los problemas sanitarios más importantes ya que esta patología genera la muerte de cerca de 500 000 sujetos anualmente en el mundo. A pesar de este panorama, el desarrollo de terapias farmacológicas efectivas contra esta enfermedad es lento y poco exitoso. En los últimos años se han diseñado y validado nuevas estrategias farmacológicas alternativas contra la adicción a drogas de abuso, como las vacunas y su uso en procedimientos farmacológicos inmunoterapéuticos para el tratamiento de esas conductas tanto en modelos de animales como en el humano. Estas nuevas estrategias experimentales están basadas en el diseño y síntesis de diversas formulaciones estructurales de vacunas terapéuticas contra las sustancias de abuso las cuales, al ser dosificadas en esquemas de inmunización activa, inducen la producción de anticuerpos séricos específicos que reconocen y se unen a estas sustancias en el espacio intravascular sistémico e impiden que crucen la barrera hematoencefálica, con lo cual disminuyen sus efectos en el cerebro. En el año 2006 nuestro grupo de trabajo en el Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz (INPRFM) logró y consolidó el diseño, síntesis, aplicación y validación de efectos terapéuticos inmunoprotectores contra recaídas al consumo adictivo de morfina/heroína, en un modelo animal con roedores y su escalamiento potencial para uso humano contra la adicción a esas sustancias. Este modelo muestra capacidades inmunogénicas (títulos altos y sostenidos de anticuerpos altamente específicos) y de inmunoprotección (atenúa el efecto de hasta 15mg/Kg sc de morfina) que los modelos estructurales de vacuna desarrollados por otros grupos de investigadores no han podido igualar. Esto lo convierte en un modelo líder de vacuna contra los efectos adictivos de la heroína y morfina.