Food allergy is most frequently the result of IgE-mediated hypersensitivity reactions. Here, we describe a chronic model in which some of the intestinal and systemic consequences of continuous egg white solution ingestion by ovalbumin-sensitized eight-week-old BALB/c mice, 6 animals per group, of both sexes, were investigated. There was a 20% loss of body weight that began one week after antigen exposure and persisted throughout the experiment (3 weeks). The sensitization procedure induced the production of anti-ovalbumin IgG1 and IgE, which were enhanced by oral antigen exposure (129% for IgG1 and 164% for IgE, compared to sensitization values). Intestinal changes were determined by jejunum edema at 6 h (45% Evans blue extravasation) and by a significant eosinophil infiltration with a peak at 48 h. By day 21 of continuous antigen exposure, histological findings were mild, with mast cell hyperplasia (100%) and increased mucus production (483%). Altogether, our data clearly demonstrate that, although immune stimulation was persistently occurring in response to continuous oral antigen exposure, regulatory mechanisms were occurring in the intestinal mucosa, preventing overt pathology. The experimental model described here reproduces the clinical and pathological changes of mild chronic food allergy and may be useful for mechanistic studies of this common clinical condition.

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Yellow fever (YF) vaccines (17D-204 and 17DD) are well tolerated and cause very low rates of severe adverse events (YEL-SAE), such as serious allergic reactions, neurotropic adverse diseases (YEL-AND), and viscerotropic diseases (YEL-AVD

It is generally accepted that distinct cytokine expression by the cellular immune response plays a critical role during the outcome of experimental as well as natural canine visceral Leishmaniasis (CVL). Despite the fact that immunoprophylaxis of CVL has become an important control strategy and protective immunity has been reported upon immunization with whole as well as purified Leishmania antigens, the cytokine profile of T-cells triggered by anti-CVL vaccines still remain to be determined. Herein, we have developed a cross-sectional analysis of German Shepherd dogs submitted to vaccination protocols with Leishvaccine (n=6) and Leishmune (n=6). Our data identified distinct immunological profiles elicited by Leishvaccine and Leishmune, with the Leishvaccine triggering a mixed, IFN-gamma and IL-4, cytokine pattern in addition to high levels of anti-Leishmania IgG1, whereas the Leishmune induced an immunological pattern characterized by enhanced levels of IFN-gamma, NO and anti-Leishmania chagasi IgG2. It was important to notice that despite the distinct immunological patterns triggered by Leishvaccine and Leishmune, the ability of both immunobiologicals to activate T-cell-derived IFN-gamma synthesis further suggesting their immunogenic potential against CVL. These findings added support to our hypothesis that both antigenic composition (whole antigen in Leishvaccine versus purified antigen in Leishmune) as well as the adjuvant nature (BGC and saponin) used for the vaccine formulation may count for the distinct activation pattern observed.