H. Kaddouri

Allergenic changes in β-lactoglobulin induced by microwave irradiation under different pH conditions

Abstract The allergenicity of β-lactoglobulin (BLG) was assayed by Ussing chamber after microwave irradiation of whey proteins at different pH values, in a murine model of BLG allergy. BALB/c mice were sensitised intraperitoneally with BLG. Serum levels of BLG-specific IgG, IgG1, IgG2a and IgE were analysed by Enzyme-Linked Immunosorbent Assay (ELISA). Local anaphylactic responses and residual allergenicity of various treated whey proteins were performed in vitro in Ussing chamber. BLG immunisation was associated with strong IgG, IgG1, IgG2a and IgE production, a significant increase in short current circuit (Isc) and high conductance (G) response. The allergenic potential of BLG was markedly reduced after microwave irradiation at 300 or 700 W of whey proteins at pH values 6.8 or 4.6 (Isc and G remained unchanged after intestine challenge with treated whey proteins). The application of microwave irradiation of whey proteins at the natural milk pH (pH 6.8) or pH 4.6 induces a significant decrease in the BLG allergenicity.

Preventive effects of royal jelly against anaphylactic response in a murine model of cow’s milk allergy

Abstract Context: Royal jelly (RJ) has long been used to promote human health. Objective: The current study investigated the preventive effects of RJ against the development of a systemic and intestinal immune response in mice allergic to cow’s milk proteins. Materials and methods: Balb/c mice treated orally for seven days with RJ at doses of 0.5, 1 and 1.5 g/kg were sensitized intraperitoneally with β-lactoglobulin (β-Lg). Serum IgG and IgE anti-β-Lg were determined by an enzyme-linked immunosorbent assay (ELISA). Plasma histamine levels, symptom scores and body temperature were determined after in vivo challenge to β-Lg. Jejunums were used for assessment of local anaphylactic responses by an ex vivo study in Ussing chambers and morphologic changes by histological analysis. Results: RJ significantly decreased serum IgG (31.15–43.78%) and IgE (64.28–66.6%) anti-β-Lg and effectively reduced plasma histamine level (66.62–67.36%) (p < 0.001) at all the doses tested. Additionally, no clinical symptoms or body temperature drops were observed in RJ-pretreated mice. Interestingly, RJ significantly reduced (p < 0.001) intestinal dysfunction by abolishing the secretory response (70.73–72.23%) induced by sensitization and prevented length aberrations of jejunal villi by 44.32–59.01% (p < 0.001). Discussion and conclusions: We speculate that using RJ may help prevent systemic and anaphylactic response in allergic mice. These effects may be related to its inhibitory effects on the degranulation of mast cells.

P088: La gelée royale prévient le développement d’une réaction anaphylactique intestinale chez la souris utilisée comme modèle d’allergie

Introduction et but de l’etude L’allergie aux proteines alimentaires est souvent associee a des signes digestifs secondaires a une reaction anaphylactique intestinale. L’utilisation de produits naturels a activite immunomodulatrice dans la prevention/le traitement de cette pathologie est d’un grand interet. La litterature rapporte des proprietes immunomodulatrices et anti-inflammatoires de la gelee royale. L’objectif de ce travail est de verifier si la gelee royale (GR) pouvait prevenir le developpement d’une reponse anaphylactique intestinale chez la souris Balb/c sensibilisee avec la proteine allergisante majeure du lait de vache, la s-lactoglobuline (s-Lg). Materiel et methodes 30 souris femelles Balb/c âgees de 4 semaines et nourries a l’aide d’un regime standard sont reparties en 3 groupes. 2 groupes, dont un recoit avant toute sensibilisation et pendant 7 jours la gelee royale a raison de 1 g/kg de poids corporel, sont immunises par voie intra-peritoneale a la (s-Lg adsorbee sur l’Alum. Le groupe 3 ne recoit aucun traitement (temoin negatif). Les anticorps seriques de type IgE anti (s-Lg sont doses par la methode immunoenzy-matique Elisa sur du sang preleve a J35. Des tests de provocation in vitro en chambre de Ussing (par mise en contact des fragments jejunaux avec la s-Lg) sont realises sur des souris rendues allergiques. Le dispositif de la chambre de Ussing permet de mesurer le courant de court circuit (Isc) et la conductance (G). Resultats et Analyse statistique Les resultats obtenus montrent l’absence de production des IgE chez les souris immunisees prealablement traitees a la GR. Chez ces memes souris, la stimulation en chambre de Ussing, des fragments jejunaux par l’antigene sensibilisant n’entraine aucune variation significative des valeurs de l’Isc traduisant l’absence d’une reaction anaphylactique locale. De plus, aucune augmentation significative de la conductance (G) des tissus n’est observee suggerant l’absence d’une atteinte des jonctions serrees. Conclusion Le pre-traitement des souris avec la gelee royale module la reponse immune systemique et intestinale. Il attenue la production des IgE anti s-Lg, diminue la reponse anaphylactique intestinale et previent l’alteration de la muqueuse intestinale en preservant l’integrite epitheliale induite par la sensibilisation.