Modulatory effects of Porphyra-derived polysaccharides, oligosaccharides and their mixture on antigen-specific immune responses in ovalbumin-sensitized mice

Although recent studies indicated the immune modulatory effects of Porphyra extract and derived polysaccharides, the impact of Porphyra-derived oligosaccharides on immune responses remains unclear. This study aimed to explore the influence of Porphyra-derived polysaccharides (PP), oligosaccharides (PO) and the PO/PP mixture on antigen-specific immune responses in ovalbumin (OVA)-sensitized mice. Daily treatment with PP, PO, or PO/PP mixture did not influence the body weight, spleen weight index, serum levels of total and OVA-specific IgG. However, the levels of IgG1, IgG2a, total and OVA-specific IgE were down-regulated. Furthermore, productions of IL-2, IFN-γ, IL-4, and IL17 from splenocytes were diminished in mice treated with PP, PO, and PO/PP mixture. In contrast, the secretion of IL-10 was slightly increased and the ratio of IL-10/IL-4 was markedly raised. These results demonstrated the modulatory effects of PP, PO, and PO/PP mixture on antigen-specific immune responses, revealing their potential to be developed as functional foods for immunomodulation.