Allergenic response induced by Pterobothrium crassicolle (Cestoda: Trypanorhyncha) extracts in murine model / Resposta alergênica induzida por extratos de Pterobothrium crassicolle (Cestoda: Trypanorhyncha) em modelo murino

Abstract The aim of this study was to determine the allergenic activity of components present in crude extracts of Pterobothrium crassicolle plerocerci (CPE) and blastocysts (CBE) obtained from Micropogonias furnieri in a murine model. Two groups of seven animals each received 50 µg of CPE or CBE on days 1, 35 and 120. Serum samples were tested by ELISA and Immunoblotting. Specific IgG and IgE levels were detected by ELISA, showing specific humoral responses for the primary immunization for both immunoglobulins and continuously growing titers for IgE. Positive Passive Cutaneous Anaphylaxis tests in rats sensitized with anti-CBE sera and tested by CBE, showed biologically, the allergenic activity of the extracts. The CPE and CBE showed some different recognition regions but both experimental groups recognized all regions of the extracts when tested for cross reactions, showing that CPE and CBE could share antigenic recognition sites.

Resumo O objetivo deste estudo foi determinar a atividade alergênica de componentes presentes em extratos crus de plerocercos (CPE) e de blastocistos de Pterobothrium crassicolle (CBE), obtidos de Micropogonias furnieri, em modelo murino. Dois grupos de sete animais receberam cada um 50 µg de CPE ou CBE nos dias 1, 35 e 120. As amostras de soro foram testadas por ELISA e Imunoblot. Os níveis específicos de IgG e IgE foram detectados por ELISA, mostrando respostas humorais específicas para a imunização primária para ambas as imunoglobulinas e títulos crescentes de IgE. Testes positivos de Anafilaxia Cutânea Passiva em ratos sensibilizados com soros anti-CBE e testados por CBE, demonstraram biologicamente, a atividade alergênica dos extratos. O CPE e o CBE evidenciaram algumas regiões de reconhecimento diferentes, mas ambos os grupos experimentais reconheceram todas as regiões dos extratos, quando testados para reações cruzadas, mostrando que o CPE e o CBE poderiam compartilhar locais de reconhecimento antigênico.

Jacareubin inhibits FcεRI-induced extracellular calcium entry and production of reactive oxygen species required for anaphylactic degranulation of mast cells.

Mast cells (MCs) are important effectors in allergic reactions since they produce a number of pre-formed and de novo synthesized pro-inflammatory compounds in response to the high affinity IgE receptor (FcεRI) crosslinking. IgE/Antigen-dependent degranulation and cytokine synthesis in MCs have been recognized as relevant pharmacological targets for the control of deleterious inflammatory reactions. Despite the relevance of allergic diseases worldwide, efficient pharmacological control of mast cell degranulation has been elusive. In this work, the xanthone jacareubin was isolated from the heartwood of the tropical tree Callophyllum brasilense, and its tridimensional structure was determined for the first time by X-ray diffraction. Also, its effects on the main activation parameters of bone marrow-derived mast cells (BMMCs) were evaluated. Jacareubin inhibited IgE/Ag-induced degranulation in a dose-response manner with an IC50 = 46 nM. It also blocked extracellular calcium influx triggered by IgE/Ag complexes and by the SERCA ATPase inhibitor thapsigargin (Thap). Inhibition of calcium entry correlated with a blockage on the reactive oxygen species (ROS) accumulation. Antioxidant capacity of jacareubin was higher than the showed by α-tocopherol and caffeic acid, but similar to trolox. Jacareubin shown inhibitory actions on xanthine oxidase, but not on NADPH oxidase (NOX) activities. In vivo, jacareubin inhibited passive anaphylactic reactions and TPA-induced edema in mice. Our data demonstrate that jacareubin is a potent natural compound able to inhibit anaphylactic degranualtion in mast cells by blunting FcεRI-induced calcium flux needed for secretion of granule content, and suggest that xanthones could be efficient anti-oxidant, antiallergic, and antiinflammatory molecules.

Safety of a proteoliposome from Neisseria meningitides as adjuvant for a house dust mite allergy vaccine.

The proteoliposome (PL) of Neisseria meningitidis serogroup B has been reported as a safe and potent vaccine adjuvant, inducing a TH1-skewed response. The present study describes a pre-clinical safety evaluation of an allergy therapeutic vaccine candidate based on purified allergens from Dermatophagoides siboney house dust mite and PL as adjuvant, both components adsorbed onto aluminum hydroxide gel. Two separate studies of acute toxicity evaluation were performed in mice and rabbits, and two repeat-dose studies were conducted in non-sensitized and allergen-sensitized Balb/c mice, respectively. The study in sensitized mice intends to model a therapeutic setting. Aerosolized allergen challenge was used in both settings to model natural respiratory exposure. In the therapeutic setting, mice were administered with three doses containing 2 µg allergen at weekly intervals [subcutaneous route] and subsequently challenged with aerosolized allergen for 6 consecutive days. Parameters of general toxicity effects were assessed via measures of behavior, body weight, food and water consumption, and macroscopic evaluation of organs. Histological examination of organs and the injection site was performed. Potential immunotoxicity effects at the systemic level were assessed by blood eosinophil counting and serum allergen specific IgE by ELISA The vaccine did not produce general or functional toxic effects of significance, at a dose up to 100 µg allergen per kg body weight. An expected local reaction at the injection site was observed, which could be attributed mostly to the immunological effect of aluminum hydroxide. The models implemented here suggest an acceptable safety profile of this vaccine for testing in clinical trials of allergy immunotherapy.

Efecto de Plectranthus amboinicus (Lour.) Spreng. tabletas sobre la anafilaxia pasiva cutánea, transmisión histaminérgica y adrenérgica / Effect of Plectranthus amboinicus (Lour.) Spreng tablets on the passive cutaneous anaphylaxis, histaminergic and adrenergic transmission.

Plectranthus amboinicus (Lour.) Spreng., más conocido en nuestro país como orégano francés, es una planta a la que se le confieren una gran cantidad de propiedades terapéuticas para el tratamiento de diferentes enfermedades dentro de las que se encuentra el asma bronquial. En el presente trabajo se realizó la evaluación de las tabletas 100 mg de Plectranthus amboinicus sobre la anafilaxia pasiva cutánea y la transmisión adrenérgica e histaminérgica. Como resultado final de este trabajo pudimos comprobar que Plectranthus amboinicus tabletas de 100 mg inhibe la anafilaxia pasiva cutánea, potencia la transmisión adrenérgica e inhibe los efectos de la histamina cuando esta interactúa con los receptores H1 presentes a nivel intestinal. Podemos concluir que las tabletas de 100 mg de Plectranthus amboinicus podrían emplearse en el tratamiento de enfermedades alérgicas tipo I y con esto justificar el uso popular de la planta en el asma bronquial.

Plectranthus amboinicus (Lour.) Spreng, well-known in our country as French origan, is a plant with many therapeutical properties for the treatment of different diseases, including bronchial asthma. In the present paper, the effect of Plectranthus amboinicus tablets (100 mg) on the passive cutaneous anaphylaxis and on the adrenergic and histaminergic transmission was evaluated. As a final result of this paper, it was possible to confirm that these tablets inhibit the passive cutaneous anaphylaxis, potentiates the adrenergic transmission, and inhibits the effects of histamine when it interacts with H1 receptors present at the intestinal level. It was concluded that the Plectranthus amboinicus tablets 100 mg could be used in the type I treatment of allergic diseases, and thus justify the popular use of this plant for bronchial asthma.