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Induction of CD8+ T cell responses against tumor cells and intracellular pathogens is an important goal of modern vaccinology. One approach of translational interest is the use of liposomes encapsulating pore-forming proteins (PFPs), such as Listeriolysin O (LLO), which has shown efficacy at priming strong and sustained CD8+ T cell responses. Recently, we have demonstrated that Sticholysin II (StII), a PFP from the sea anemone Stichodactyla helianthus, co-encapsulated into liposomes with ovalbumin (OVA) was able to stimulate, antigen presenting cells, antigen-specific CD8+ T cells and anti-tumor activity in mice. In the present study, we aimed to compare StII and LLO in terms of their abilities to stimulate dendritic cells and to induce major histocompatibility complex (MHC) class I restricted T cell responses against OVA. Interestingly, StII exhibited similar abilities to LLO in vitro of inducing dendritic cells maturation, as measured by increased expression of CD40, CD80, CD86 and MHC-class II molecules, and of stimulating OVA cross-presentation to a CD8+ T cell line. Remarkably, using an ex vivo Enzyme-Linked ImmunoSpot Assay (ELISPOT) to monitor gamma interferon (INF-γ) producing effector memory CD8+ T cells, liposomal formulations containing either StII or LLO induced comparable frequencies of OVA-specific INF-γ producing CD8+ T cells in mice that were sustained in time. However, StII-containing liposomes stimulated antigen-specific memory CD8+ T cells with a higher potential to secrete IFN-γ than liposomes encapsulating LLO. This StII immunostimulatory property further supports its use for the rational design of T cell vaccines against cancers and intracellular pathogens. In summary, this study indicates that StII has immunostimulatory properties similar to LLO, despite being evolutionarily distant PFPs.

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OBJETIVOS. Conocer la prevalencia del consumo de cannabis en adolescentes, así como su asociación con rasgos de la personalidad, disfunción familiar y otras variables. SUJETOS Y MÉTODOS. Estudio descriptivo, en una muestra de 1.568 adolescentes de 12 a 18 años de los Institutos de Educación Secundaria del área de salud de Lanzarote, elegidos mediante muestreo por conglomerados. Como instrumento de medida se empleó un cuestionario autoadministrado de 41 ítems, que incluía 19 sobre la forma de pensar, sentir o actuar. RESULTADOS. Cuarenta y nueve adolescentes (3,1%; IC 95%: 2,2-4) consumían habitualmente cannabis y 166 (10,6%; IC95%: 9,1-12,1) lo hacían esporádicamente. El consumo aumentaba con la edad y era más frecuente en los varones. El consumo esporádico o habitual de cannabis se asoció sobre todo con el consumo habitual de tabaco y/o alcohol, haber consumido cocaína alguna vez y haberse emborrachado 5 o más veces. Los consumidores habituales de cannabis tenían mayor prevalencia de síntomas depresivos (28,6%) (OR = 3,1 respecto a los no consumidores; p < 0,001), de disfunción familiar (27,1%) (OR = 10,5; p < 0,001) y era más frecuente en hijos de madres bebedoras habituales. El consumo habitual de cannabis se asoció a diferentes indicadores de personalidad, pero la OR de asociación fue superior en aquéllos relacionados con la conducta antisocial. CONCLUSIONES. El consumo de cannabis en los adolescentes es un problema de elevada magnitud, siendo más frecuente en los varones de mayor edad consumidores de tabaco y/o alcohol que alguna vez consumieron cocaína, así como en aquéllos con mayor número de borracheras (AU)

OBJECTIVES. To know the prevalence of the consumption of cannabis in adolescents, as well as its association with personality features, familial dysfunction and another variables. METHODS. Descriptive study, in a sample of 1568 adolescents of 12 to 18 years of high schools of Lanzarote health area, chosen through sampling by conglomerates. A questionnaire of 41 items, that included 19 items about way to think, feel or act, was used as measurement instrument. RESULTS. Forty-nine adolescents (3.1%; 95% CI: 2.2-4) consumed cannabis habitually and 166 (10.6%; 95% CI:9.1-12.1) did it sporadically. Consumption increased with the age and was more frequent in men. The sporadic or habitual consumption of cannabis associated mainly with habitual consumption of tobacco and/ or alcohol, to have consumed cocaine sometimes and to have intoxicated 5 or more times. The habitual consumers of cannabis had greater prevalence of depressive symptoms (28.6%) (OR = 3.1 respect to non-consumers; p < 0.001), of familial dysfunction (27.1%) (OR = 10.5; p < 0.001), and was more frequent in children of mothers habitual drinkers. The habitual consumption of cannabis associated to different personality indicators but the OR of association was superior in those related with antisocial conduct. CONCLUSIONS. The consumption of cannabis in adolescents is a problem of high magnitude, being more frequent in older men, the consumers of tobacco and/or alcohol, who have ever consumed cocaine, and in those with greater number of drunkenness (AU)

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We investigated the influence of dehydration-rehydration vesicles (DRV) phospholipid composition and the addition of other components on human recombinant epidermal growth factor (hrEGF) encapsulation efficiency and its release from liposomes. Encapsulation of EGF into DRV composed of phosphatidylcholine with different unsaturation levels was around 20-35%. The best result was obtained with dipalmitoyl phosphatidylcholine: cholesterol (DPPC:Ch) liposomes (35%) corresponding to the lowest hrEGF release during one month of storage. Even with this phospholipid composition, modification of the DRV procedure by including an extrusion step did not improve hrEGF encapsulation efficiency, rendering less stable particles. The inclusion of recombinant P64k from Neisseria meningitidis (rP64k), as such or conjugated to hrEGF, decreased the encapsulation efficiency of the latter protein into DRV or freeze and thaw multilamellar vesicles (FATMLV). The hrEGF release from liposomes could be related to the interaction between this polypeptide and the bilayer, as evidenced by increased carboxyfluorescein release from hrEGF-DRV; less susceptibility to fluorescence quenching by acrylamide in the presence of liposomes; and a measurable decrease of phospholipid phase transition Delta enthalpy (DeltaH). DRV comprising saturated phospholipids (DPPC:Ch or distearoyl phosphatidylcholine [DSPC]:Ch) and containing the conjugate EGF-P64k induced a more efficient immune response against hrEGF than unsaturated phospholipid and alum in terms of total IgG, IgG(2a), and IgG(2b) subclasses and the ability of antibody to inhibit the interaction of the EGF receptor with hrEGF.

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The water activity in dimyristoylphosphatidylcholine (DMPC) decreases by 60% when the lipid is dehydrated in the presence of trehalose concentrations higher than 0.02 M. In contrast, sucrose in concentrations 10 times higher produced only a 20% decrease in the water activity in the sample. Titrations of a DMPC solution in chloroform yielded 14 water molecules per lipid when pure water was added and seven water molecules per lipid when the titration was done with 0.025 M trehalose. The same concentrations of sucrose produced a turbid solution, which made it impossible to quantify the number of water molecules per lipid. Lipid monolayers spread on an air/water interface showed a decrease from 480 mV in pure water to 425 mV in 0.1 M trehalose. However, the same concentrations of sucrose produced an increase of less than 100 mV. Results obtained with Fourier transform infrared spectroscopy (FTIR) under the same conditions denoted that trehalose binds to the carbonyl groups, while sucrose showed no specific binding. It is concluded that per lipid molecule, 11 of 14 water molecules can be replaced by three trehalose molecules. About four are displaced by changes in the water activity of the bulk solution, and seven by specific interactions with the phospholipids. In this last case, at least two of them are linked to the carbonyls, and this appears to be the cause of the decrease in the dipole potential of the membrane. In contrast, four sucrose molecules displace only three water molecules per lipid, with no effect on the dipole potential or the carbonyl groups.

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The physical properties conferred to DPPC bilayers by including neoglycolipids composed by two different trisaccharides: mannose-mannose-mannose (3M) and glucose-mannose-glucose (GMG) attached to a cholesterol (cho) and a distearylglycerol (diC18) lipid moiety by a spacer were evaluated by means of the measurement of the electrokinetic potential and interfacial fluorescent probes. The phase properties measured with diphenylhexatriene (DPH) were correlated with the surface properties measured with merocyanine 540, dansyl, and Laurdan probes. The results show that the surface properties of large unilamellar vesicles depend on the sugar exposure to the water phase and also on the hydrocarbon moiety by which it is anchored to the bilayer. The combination of the cholesterol moiety with the saccharide attenuates the cooperativity decrease induced by the cholesterol moiety without the sugar portion. The neoglycolipid GMG-diC18 promotes opposite effects affecting slightly the cooperativity at the hydrocarbon core of DPPC and displacing the phase transition temperature to higher values. The presence of neoglycolipid with diC18 introduces defects in the packing at the interface of the membrane in the gel state. It is concluded that a relatively low proportion of neoglycolipids affects significantly the interfacial properties of DPPC bilayers in large unilamellar vesicles in the absence of changes at the membrane bulk at 25 degrees C.

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A new neoglycolipid (AgH-1) bearing carbohydrate units that mimics the antigenic determinant of the O-blood group was synthesized and the effect of its incorporation in dipalmitoylphosphatidylcholine (DPPC): cholesterol liposomes was evaluated. The results obtained show that AgH-1 is readily incorporated into DPPC:cholesterol liposomes. The conditions leading to the optimal incorporation are the result of a compromise between incorporation efficiency and incorporation extent. The presence of AgH-1 produces liposomes of smaller size, with only small changes in the properties of the bilayer. However, the data obtained employing diphenylhexatriene and laurodan as fluorescence probes and merocyanine 540 as optical probe suggest that AgH-1 incorporation leads to a small rigidization of the liposomes at temperatures lower than ca. 42 degrees C.

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