Active vaccination attenuates the psychostimulant effects of α-PVP and MDPV in rats.

Recreational use of substituted cathinones continues to be an emerging public health problem in the United States; cathinone derivatives α-pyrrolidinopentiophenone (α-PVP) and 3,4-methylenedioxypyrovalerone (MDPV), which have been linked to human fatalities and show high potential for abuse liability in animal models, are of particular concern. The objective of this study was to develop an immunotherapeutic strategy for attenuating the effects of α-PVP and MDPV in rats, using drug-conjugate vaccines created to generate antibodies with neutralizing capacity. Immunoconjugates (α-PVP-KLH and MDPV-KLH) or the control carrier protein, keyhole limpet hemocyanin (KLH), were administered to groups (N = 12) of male Sprague-Dawley rats on Weeks 0, 2 and 4. Groups were administered α-PVP or MDPV (0.0, 0.25, 0.5, 1.0, 5.0 mg/kg, i.p.) in acute drug challenges and tested for changes in wheel activity. Increased wheel activity produced by α-PVP or MDPV in the controls was attenuated in the α-PVP-KLH and MDPV-KLH vaccinated groups, respectively. Rectal temperature decreases produced by MDPV in the controls were reduced in duration in the MDPV-KLH vaccine group. A separate group (N = 19) was trained to intravenously self-administer α-PVP (0.05, 0.1 mg/kg/inf) and vaccinated with KLH or α-PVP-KLH, post-acquisition. Self-administration in α-PVP-KLH rats was initially higher than in the KLH rats but then significantly decreased following a final vaccine booster, unlike the stable intake of KLH rats. The data demonstrate that active vaccination provides functional protection against the effects of α-PVP and MDPV, in vivo, and recommend additional development of vaccines as potential therapeutics for mitigating the effects of designer cathinone derivatives.

Oligosaccharides and peptide displayed on an amphiphilic polymer enable solid phase assay of hapten specific antibodies.

Copovidone, a copolymer of vinyl acetate and N-vinyl-2-pyrrolidone, was synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization, and after deacetylation the polymer was functionalized by introduction of amino, azide, and alkyne pendant groups to allow attachment of glycans and peptide. Candida albicans ß-mannan trisaccharides 1 and 2 and M. tuberculosis arabinan hexasaccharide 3 with appropriate tethers were conjugated to the polymers by squarate or click chemistry. C. albicans T-cell peptide 4 bearing a C-terminal ε-azidolysine was also conjugated to copovidone by click chemistry. The resulting conjugates provide convenient non-protein-based antigens that are readily adsorbed on ELISA plates, and display excellent characteristics for assay of antibody binding to the haptenic group of interest. Copovidone and BSA glycoconjugates exhibited similar adsorption characteristics when used to coat ELISA plates, and both conjugates were optimal when used as coating solutions at low nanogram/mL concentrations. Provided that the copovidone conjugated glycan is stable to acid, assay plates can be easily processed for reuse at least three times without detectable variation or degradation in ELISA readout.

Different binding modes of free and carrier-protein-coupled nicotine in a human monoclonal antibody.

Nicotine is the principal addictive component of tobacco. Blocking its passage from the lung to the brain with nicotine-specific antibodies is a promising approach for the treatment of smoking addiction. We have determined the crystal structure of nicotine bound to the Fab fragment of a fully human monoclonal antibody (mAb) at 1.85 Å resolution. Nicotine is almost completely (>99%) buried in the interface between the variable domains of heavy and light chains. The high affinity of the mAb is the result of a charge-charge interaction, a hydrogen bond, and several hydrophobic contacts. Additionally, similarly to nicotinic acetylcholine receptors in the brain, two cation-π interactions are present between the pyrrolidine charge and nearby aromatic side chains. The selectivity of the mAb for nicotine versus cotinine, which is the major metabolite of nicotine and differs in only one oxygen atom, is caused by steric constraints in the binding site. The mAb was isolated from B cells of an individual immunized with a nicotine-carrier protein conjugate vaccine. Surprisingly, the nicotine was bound to the Fab fragment in an orientation that was not compatible with binding to the nicotine-carrier protein conjugate. The structure of the Fab fragment in complex with the nicotine-linker derivative that was used for the production of the conjugate vaccine revealed a similar position of the pyridine ring of the nicotine moiety, but the pyrrolidine ring was rotated by about 180°. This allowed the linker part to reach to the Fab surface while high-affinity interactions with the nicotine moiety were maintained.

Structurally distinct nicotine immunogens elicit antibodies with non-overlapping specificities.

Nicotine conjugate vaccine efficacy is limited by the concentration of nicotine-specific antibodies that can be reliably generated in serum. Previous studies suggest that the concurrent use of 2 structurally distinct nicotine immunogens in rats can generate additive antibody responses by stimulating distinct B cell populations. In the current study we investigated whether it is possible to identify a third immunologically distinct nicotine immunogen. The new 1'-SNic immunogen (2S)-N,N'-(disulfanediyldiethane-2,1-diyl)bis[4-(2-pyridin-3-ylpyrrolidin-1-yl)butanamide] conjugated to keyhole limpet hemocyanin (KLH) differed from the existing immunogens 3'-AmNic-rEPA and 6-CMUNic-BSA in linker position, linker composition, conjugation chemistry, and carrier protein. Vaccination of rats with 1'-SNic-KLH elicited high concentrations of high affinity nicotine-specific antibodies. The antibodies produced in response to 1'-SNic-KLH did not appreciably cross-react in ELISA with either 3'-AmNic-rEPA or 6-CMUNic-BSA or vice versa, showing that the B cell populations activated by each of these nicotine immunogens were non-overlapping and distinct. Nicotine retention in serum was increased and nicotine distribution to brain substantially reduced in rats vaccinated with 1'-SNic-KLH compared to controls. Effects of 1'-SNic-KLH on nicotine distribution were comparable to those of 3'-AmNic-rEPA which has progressed to late stage clinical trials as an adjunct to smoking cessation. These data show that it is possible to design multiple immunogens from a small molecule such as nicotine which elicit independent immune responses. This approach could be applicable to other addiction vaccines or small molecule targets as well.

Effects of a reversible beta-tryptase and trypsin inhibitor (RWJ-58643) on nasal allergic responses.

BACKGROUND: beta-Tryptase is a multifunctional mast cell serine protease released during mast cell degranulation and tryptase/trypsin inhibitors are a novel potential therapeutic approach for allergic inflammatory diseases. OBJECTIVES: This study was performed to assess the effects of RWJ-58643 on nasal symptoms, eosinophil influx, and cytokine and chemokine release following nasal allergen challenge (NAC). METHODS: Male patients with grass pollen allergic rhinitis (n=16) out of season received single doses of RWJ-58643 (100, 300, 600 microg) or matched placebo given 30 min before NAC in a double-blind, randomized crossover design. A single dose of 200 microg budesonide was studied in an open-label extension phase. NAC was performed with Timothy grass pollen (ALK) via a nasal device, and nasal lavage was performed at times 0 (pre-drug, pre-allergen), 0.5 (30 min post-drug, pre-NAC) 1.5, 2.5, 4.5, 6.5, 8.5, and 24 h after drug administration. Nasal lavage mediators were analysed using a sensitive multiplexed bead immunoassay system. RESULTS: Low-dose RWJ-58643 (100 microg) and budesonide (200 microg) significantly reduced symptoms, eosinophils and levels of IL-5 following NAC. However, higher doses of RWJ-58643 (300 and 600 microg) caused a late eosinophilia and preceding increases in IL-5 compared with placebo. CONCLUSIONS: This study suggests that combined beta-tryptase and trypsin inhibition has therapeutic potential in allergic inflammation, however, this property is dose responsive and higher doses are ineffective and may cause eosinophilia.

Modulation of endothelial monolayer permeability induced by plasma obtained from lipopolysaccharide-stimulated whole blood.

The aim of this study was to elucidate the time course of the permeability response of endothelial monolayers after exposure to plasma obtained from lipopolysaccharide (LPS)-treated human whole blood; to investigate the role of apoptosis in monolayer permeability, and to inhibit the permeability increase, particularly after addition of the plasma stimulus. Human umbilical vein endothelial cells (HUVEC) were cultured on semiporous membranes and the permeability for albumin was measured after exposure, according to different schedules, to LPS-conditioned plasma. Apoptotic HUVEC were measured by both flow cytometry and ELISA. A variety of agents, including antibodies against cytokines, inhibitors of NF-kappaB, and a caspase inhibitor, were added to HUVEC, either prior to or after the stimulus. A maximum increase of the permeability was achieved after 4-6 h of exposure to LPS-conditioned plasma. This response was not accompanied by an increase in the number of apoptotic HUVEC. Administration of antibodies against both Tumour Necrosis Factor-alpha (TNF-alpha) and Interleukin-1beta (IL-1beta) to HUVEC within 1 h after stimulation significantly reduced the permeability increase. Similarly, pyrollidine di-thiocarbamate (PDTC), but not N-acetylcysteine, could prevent the permeability response, and was still effective when added within 2 h after LPS-conditioned plasma. The TNF-alpha/IL-1beta signal present in LPS-conditioned plasma appears to increase endothelial permeability through intracellular pathways that very likely involve the activation of NF-kappaB. Although poststimulatory inhibition of the permeability response proves to be possible with agents such as PDTC, the window of opportunity appears very small if placed in a clinical perspective.

Dissociation between sex differences in the immunological, behavioral, and physiological effects of kappa- and delta-opioids in Fischer rats.

RATIONALE: The sex of the individual can have a profound effect on sensitivity to the effects of opioids. Recently, our laboratory provided the first evidence that females may be more sensitive to the immune-altering effects of mu-opioids than males. However, it remains unknown whether kappa- and delta-opioids produce sexually dimorphic effects on immune responses. OBJECTIVE: The present study sought to determine whether kappa- and delta-opioids produce differential immunological effects in males and females using the memory-T-cell-dependent in vivo inflammatory response contact hypersensitivity (CHS). As sex differences in the magnitude of opioid effects can be outcome-specific, additional experiments were conducted to compare the immunological effects of kappa- and delta-opioids with other behavioral and physiological effects. MATERIALS AND METHODS: Contact hypersensitivity was induced in male and female Fischer rats. Prior to elicitation of CHS, animals were administered selected doses of the kappa-opioid spiradoline (0.2-20 mg/kg), delta-opioid SNC80 (1-10 mg/kg), or vehicle. The antinociceptive and diuretic effects of spiradoline were also assessed in males and females, as were the locomotor effects of SNC80. RESULTS: Spiradoline produced significantly greater enhancement of CHS in females than males, but produced comparable antinociceptive and diuretic effects in both sexes. By contrast, SNC80 did not significantly affect the course of CHS in either sex, but females were significantly more sensitive to its locomotor stimulatory effects. CONCLUSIONS: These results demonstrate that females are more sensitive than males to the CHS-altering effects of spiradoline and that sex differences in the magnitude and direction of opioid-induced sex differences are outcome dependent.

Morphine suppresses primary humoral immune responses by a predominantly indirect mechanism.

Morphine suppresses humoral immune responses, causes thymic hypoplasia and suppresses NK (natural killer) activity in animal models. There is evidence that thymic hypoplasia and NK suppression are predominantly mediated by indirect mechanisms. The mechanism of morphine-induced humoral immunosuppression is less certain. Recent reports suggest that morphine and other opioids can directly act on cells of the immune system to suppress the generation of antibody-forming cells (AFC) in Mishell-Dutton cultures. The present study was designed to assess the roles of direct and indirect mechanisms in morphine-induced suppression of humoral immunity. Splenocytes from mice treated with morphine by s.c. implantation of a slow-release 75 mg pellet were dysfunctional in Mishell-Dutton cultures. Exposure to morphine in vivo for 12 or 24 hr caused significant suppression of the AFC production stimulated by sheep erythrocytes in Mishell-Dutton cultures. In contrast, direct addition of morphine or the kappa selective opioid agonist U50,488H to Mishell-Dutton cultures under a variety of conditions had little or no effect on AFC generation. These results indicate that suppression of humoral responses by morphine is not primarily mediated by direct action of morphine on the immune system. Suppression of AFC responses by administration of morphine in vivo was substantially blocked by treating mice with the glucocorticoid antagonist RU 38486, suggesting that glucocorticoids may be involved in the indirect mechanism by which morphine causes splenocyte dysfunction.

Antibodies with high affinity for spiroperidol--II. Cross reactivity with iodobenzamide and domperidone.

Three radioligands, 3H-spiroperidol (3H-SPD), 3H-domperidone (3H-DOMP) and 125I-iodobenzamide (125I-IBZM), were used to investigate the antibody response to two haptens, aminospiroperidol (NH2SPD) and N-aminophenethylspiroperidol (NAPS). Although structurally different, these three radioligands each bind with high affinity to the D2 dopamine receptor. Antibodies with high affinity for 3H-SPD were elicited in rabbits following immunization with the hapten NH2SPD covalently linked to keyhole limpet hemocyanin (KLH). In addition, antibodies in the rabbit anti-NH2SPD antisera bound 125I-IBZM or 3H-DOMP. Rabbit anti-NH2SPD antibodies that bound 125I-IBZM or 3H-DOMP were found to have higher affinity for IBZM or DOMP, respectively, than for SPD. The binding properties of the anti-NH2SPD antibodies that bound 3H-SPD, 125I-IBZM and 3H-DOMP were characterized using a panel of competitive inhibitors and each radioligand appeared to bind to a distinct subpopulation of anti-NH2SPD antibodies. BALB/c mice were immunized with NH2SPD-KLH or NAPS-KLH. A population of antibodies that bound 3H-SPD and a population of antibodies that bound 3H-DOMP were detected. The population of antibodies that bound 3H-DOMP was found to be heteroclitic for DOMP, since DOMP was a more effective competitive inhibitor than SPD. Binding sites for 125I-IBZM were not detected in either the anti-NH2SPD or the anti-NAPS BALB/c antisera. However, two anti-NAPS monoclonal antibodies, N6-24 and N6-29, that bind 3H-SPD with high affinity (Kd = 10(-9) M), were also found to bind IBZM (Ki = 2 x 10(-7) M) and DOMP (Ki = 2 x 10(-6) M). Although anti-NH2SPD and anti-NAPS antibodies were identified that appeared to bind 3H-SPD, 3H-DOMP or 125I-IBZM with high affinity, none of the populations of polyclonal antibodies or monoclonal antibodies bound all three ligands with high affinity.