Sulfated oligosaccharide of Gracilaria lemaneiformis protect against food allergic response in mice by up-regulating immunosuppression

Sulfated oligosaccharide of Gracilaria lemaneiformis (GLSO) was prepared from sulfated polysaccharides which possessed antiallergic activity by degradation with high temperature and pressure combined with vitamin C treatment. The present study demonstrated that GLSO could attenuate food anaphylaxis, and inhibit the production of immunoglobulin E, histamine, and related cytokines in both prevention and therapy ovalbumin-induced mice model. Additionally, the gut microbiota analysis revealed that GLSO markedly rescued OVA-induced changes in the Firmicutes to Bacteroidetes ratio. Following flow cytometry, GLSO was found to suppress the subpopulation of T helper 2 and B cells, and significantly up-regulate regulatory T cells (Tregs) differentiation. Furthermore, GLSO-mediated immunosuppression could be verified by co-culturing Tregs sorted from GLSO-treated mice and CD4+ T cells or mast cells. In a word, GLSO attenuated food anaphylaxis through the regulation of gut microbiota and induction of immunosuppression. GLSO had the potential to be used as a nutrient component against food allergy.