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Introduction: Incidence of food allergy has increased in the recent years yet no treatment is available except for allergen avoidance; therefore, new therapies are in development involving probiotic bacteria and human milk oligosaccharides. Food allergy results from an unbalanced T helper cell population favouring Th2/Th1 cells. Human milk oligosaccharides (HMOs) and probiotic bacteria have been shown to modulate the immune system; therefore they might be proposed as potential therapies against allergic diseases. In this study, HMOs 2’ fucosyllactose and 6’ sialyllactose, and probiotic strains Lactobacillus reuteri DSM17938 and Lactobacillus rhamnosus JB-1 were used as treatments against ovalbumin-induced food allergy in mice. Results: The effects of oral treatment with probiotics and prebiotics on anaphylactic symptoms induced by oral ovalbumnin (OVA) challenge in sensitized mice were investigated. Mast cell functions in response to oral HMO treatment were also measured in the passive cutaneous anaphylaxis model and direct effects on IgE mediated degranulation of mast cells were assessed. Daily oral treatment with 2’ fucosyllactose or 6’ sialyllactose attenuated food allergy symptoms including diarrhea and hypothermia. Treatment with HMOs also suppressed antigen induced increases in mouse mast cell protease-1 in serum and mast cell numbers in the intestine. These effects were associated with increases in the CD4+CD25+IL-10+ cell populations in the Peyer’s patches and mesenteric lymph nodes, while 6’ sialyllactose directly inhibited mast cell degranulation In-vitro, at high concentrations. Effects of direct probiotic treatment were less dramatic. Lactobacillus reuteri DSM17938 decreased diarrhea and mMCP-1 in the colon while increasing IL-10 production. While Lactobacillus rhamnosus JB-1 increased IL-10 and IFN-γ while decreasing TNF-α from stimulated splenocytes but had no effect on symptoms. Conclusion: Our studies suggest that 2’ fucosyllactose and 6’ sialyllactose reduce the symptoms of food allergy through the induction of IL-10+ T regulatory cells and indirect stabilization of mast cells. Thus, human milk oligosaccharides may have greater therapeutic potential in food allergy than probiotic treatment. Thesis Master of Science in Medical Sciences (MSMS) |
