Yvonne VissersCurrently at:
Research Scientist in Allergy
Nutrition and Health Department
Nestlé Research Centre
P.O. Box 44
CH-1000 Lausanne 26
Phone: 0041 (0)21 785 9504
e-mail: Yvonne VissersPublications
Thesis project at CBI:
The PhD thesis is part of the EuroPrevall-project that is an EU-funded multidisciplinary integrated project which aims to improve quality of life for food allergic people. The PhD project will be part of the work package with the title: ‘Assessing the influence of food matrix, food processing and digestion on allergenicity’.
Background and problem formulationAllergic reactions to foods can have serious health consequences, ranging from nausea, eczema or vomiting to a potentially life-threatening anaphylactic shock. The basic mechanisms that underlie allergic reactions are largely known and are summarized in figure 1.
Many parameters are of influence on the occurrence and severity of allergic reactions, such as individual-related parameters, geographical parameters and presentation of allergens to the immune system (e.g. amounts, degree of processing and digestion, embedding in food matrix components). Part of this project focuses on the impact of processing on the immunologic reactivity of allergenic (food) proteins, such as Ara h 1 and Ara h 2/6 from peanut.
Another focus of the project is on immunomodulatory properties of lactic acid bacterial strains (LAB). LAB recently gained interest in relation to allergy as they might down regulate the Th2 response by inhibition of IL-4 and IL-13 production by Th2 cells and skewing the T cell response towards Th1. Immuno-modulating properties of LAB are known to be strain-specific.
The objective of this project is to analyze the impact of processing on the immuno-(allergo-) reactivity of mainly peanut proteins.
Furthermore, several LAB are screened for their immunomodulating properties and selected strains are tested using peripheral blood mononuclear cells (PBMC) of allergic patients.
Various allergenicity assays have been performed, amongst others T-cell polarisation assays based on cultures of PBMC from allergic and control patients. A cell culture system with rat basophilic leukaemia cells (RBL) has been set up using IgE-containing patients’ sera to assess the ability of the allergens to respond. Allergens, processed or not have been tested using this model. Furthermore, inhibition studies and basophil histamine release tests are performed in cooperation with partners of the EuroPrevall project.
The immunomodulatory effects of several strains of three Lactobacillus species are assessed. All strains were capable of inducing IL-1β, IL-10, IFN-γ and TNF-α. L. plantarum strains showed a higher induction capacity of IFN-γ and TNF-α compared to the L. acidophilus and L. casei/paracasei strains. A larger variation in effects between species compared to within-species was observed.The most promising strains regarding beneficial immunomodulating capacities in allergic diseases have been tested more extensively using hPBMC of birch pollen allergic patients.