Supplementary Material for: Dietary Fructo-Oligosaccharides Attenuate Early Activation of CD4+ T Cells Which Produce both Th1 and Th2 Cytokines in the Intestinal Lymphoid Tissues of a Murine Food Allergy Model

Background: Fructo-oligosaccharides (FOS) are prebiotic
agents with immunomodulatory effects involving improvement of the
intestinal microbiota and metabolome. In this study, we investigated the
cellular mechanisms through which FOS modulate intestinal
antigen-specific CD4+ T cell responses in food allergy, using OVA23-3 mice. Methods:
OVA23-3 mice were fed an experimental diet containing either ovalbumin
(OVA) or OVA and FOS for 1 week. Body weight and mucosal mast cell
protease 1 in the serum were measured as the indicator of intestinal
inflammation. Single-cell suspensions were prepared from intestinal and
systemic lymphoid tissues for cellular analysis. Cytokine production was
measured by ELISA. Activation markers and intracellular cytokines in
CD4+ T cells were analyzed by flow cytometry. Activated CD4+ T cells were purified to examine cytokine production. Results:
Dietary intake of FOS provided moderate protection from the intestinal
inflammation induced by the OVA-containing diet. FOS significantly
reduced food allergy-induced Th2 cytokine responses in intestinal
tissues but not in systemic tissues. FOS decreased OVA diet-induced
IFN-γ+IL-4+ double-positive CD4+ T cells and early-activated CD45RBhighCD69+CD4+ T cells in the mesenteric lymph nodes. Furthermore, we confirmed that these CD45RBhighCD69+CD4+ T cells are able to produce high levels of IFN-γ and moderate level of IL-4, IL-10, and IL-13. Conclusions:
Dietary intake of FOS during the development of food allergy attenuates
the induction of intestinal Th2 cytokine responses by regulating early
activation of naïve CD4+ T cells, which produce both Th1 and
Th2 cytokines. Our results suggest FOS might be a potential food agent
for the prevention of food allergy by modulating oral sensitization to
food antigens.