Introduction: The incidence of food allergy has increased substantially in developed countries, with limited treatment and/or prevention options. Milk oligosaccharides have shown to modulate immune responses by serving as prebiotic substrates for the intestinal microbiota. However, some studies suggest that oligosaccharides may exert direct immunomodulatory effects, suggesting their therapeutic potential in preventing allergic diseases. We hypothesized that specific milk oligosaccharides including 6’sialyllactose, 2’fucosylactose, 3’sialyllactose and lacto-N-neotetraose may directly exert immunomodulatory effects on dendritic cells (DCs) and epithelial cells (ECs) by altering their phenotype and/or function in vitro.
Methods: The effects of milk oligosaccharides (MOs) on bone-marrow derived DCs and the T84 and MODE-K epithelial cell lines were studied via direct treatment, in vitro. The expression of immunomodulatory cytokines and maturation markers were assessed to measure the effect of MOs on DC phenotype. Pro- and anti-inflammatory cytokines as well as NFκB p65 activity were measured to assess the effect of MOs on DC and EC function. In addition, in vitro stimulation of CD23 with IgE-Antigen complexes were used to study the effects of MOs on ECs in relation to allergy. Lastly, inhibitory antibodies for Siglec-F and PPARγ were used to elucidate the mechanism used by specific MOs to exert their effects.
Results: Of the oligosaccharides studied, 6’siallylactose has direct immunomodulatory effects on DC phenotype and on DC and EC function at high concentrations. 6’sialyllactose increased DC expression of IL-10 and HO-1; it also increased CpG- and LPS- induced IL-10 release and decreased IL-12p70 release. Blocking the PPARγ receptor with GW9662 resulted in attenuation of this latter effect on IL-12p70 release. 6’sialyllactose reduced TNF-α induced IL-8 to a small but statistically significant extent and mKC to a great extent in T84 and MODE-K cells, respectively. In addition, 6’sialyllactose reduced IgE-Antigen stimulated release of IL-8 and CCL20, as well as NFκB p65 activity. Pre-treatment of cells with GW9662 resulted in attenuation of the effect of 6’SL on IL-8 release and p65 activation. In addition, 2’fucosylactose reduced CCL20 release and NFκB activity substantially, but these effects were not exerted via PPARγ.
Conclusion: Some oligosaccharides are able to directly modulate the inflammatory response in DCs and ECs, via pathways involving PPARγ activation and/or NFκB inhibition. / Thesis / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/18268 |
| Date | 21 November 2015 |
| Creators | Zehra, Sehrish |
| Contributors | Forsythe, Paul, Medical Sciences |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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