Liu Fahui
Tolerance induction of cow milk allergy
Fahui Liu
fahui.liu@wur.nl
Supervisors:
Prof. Dr. Ir. M.A.J.S. van BoekelProf. Dr. H.J. Wichers
Dr. Ir. K.A. Hettinga
Project term:
September 2011- September 2015
Sponsors:
WU/VLAG
Introduction
Cow’s milk is one of the leading causes of food allergy especially in infants. Cow’s milk allergy (CMA) is a prevalent problem that has been receiving increasing attention. However, most studies have shown the prognosis of developing immune tolerance to cow’s milk to be good, with the majority outgrowing their allergy by the age of 3 years. It was reported that intensely heated (baked) milk products contribute to the development of immune tolerance to cow’s milk allergens. Also the process of outgrowing CMA can be accelerated by adding intensely heated milk into patients’ diets[1].Heat treatment may change the chemical and physical properties of milk allergens. This will not only influence the allergenicity of these allergens and the resistance of allergens to gastrointestinal digestion, but also change the ways by which allergens pass through the mucosal barrier. Subsequently, immune response will be changed by different kinds of lymphocytes and cytokines.
Aim
The aim of this project is to study the impact of intensely heated milk on the development of immune tolerance. Specifically, there are three aims in this project:To analyse the impact of intense heat treatment on the chemical and physical properties of milk proteins;
To test transport efficiency of intensely heated antigens in the intestine;
To investigate the immunological factors that are responsible for the development of tolerance to cow’s milk allergens.
Research approach
1. A food model mainly consists of milk proteins and wheat carbohydrates will bebuilt. This model will be used to simulate bakery process of some commercial products. Physical properties of the allergens in the model will be tested. To test the effect of thermal treatment on immunoreactivity of allergens, ELISA assay will be performed using patients’ serum pool. The quantity of available amino groups will be determined by the modified ortho-phthaldialdehyde (OPA) method.
2. The allergens will be applied to in vitro gastrointestinal digestion. Transcytosis efficiency of allergens will then be analysed using Caco-2 cells, with special emphasis on the correlation of transfer efficiency and physical properties of allergens. Fluorescently-labelled allergens will be used to analyse the way by which they pass through epithelium in the intestine of a murine model. In addition, DCs in the intestine play an important role in the uptake of allergens. The role of DCs in antigens presentation of heated milk proteins will be addressed.
3. Finally, impact of allergens on PBMC induced proliferation and cytokine production capacity will be measured, harvested PBMCs will be characterized using Flow Cytometry. The production of IL-35, TNF-α, TGF-ß, IL-10, CD63, CD203c and some other cytokines will be tested by ELISA, Cytometric Bead Array and Flow Cytometry.