Ovalbumin-Induced Epithelial Activation Directs Monocyte-Derived Dendritic Cells to Instruct Type 2 Inflammation in T Cells Which Is Differentially Modulated by 2′-Fucosyllactose and 3-Fucosyllactose

Abstract

Allergic sensitization starts with epithelial cell activation driving dendritic cells (DCs) to instruct T helper 2 (Th2) cell polarization. Food allergens trigger intestinal epithelial cell (IEC) activation. Human milk oligosaccharides may temper the allergic phenotype by shaping mucosal immune responses.We investigated in vitro mucosal immune development after allergen exposure by combining ovalbumin (OVA)-preexposed IEC with monocyte-derived DCs (OVA-IEC-DCs) and subsequent coculture of OVA-IEC-DCs with Th cells. IECs were additionally preincubated with 2′FL or 3FL.OVA activation increased IEC cytokine secretion. OVA-IEC-DCs instructed both IL13 (<i>p</i> < 0.05) and IFNγ (<i>p</i> < 0.05) secretion from Th cells. 2′FL and 3FL permitted OVA-induced epithelial activation, but 2′FL-OVA-IEC-DCs boosted inflammatory and regulatory T-cell development. 3FL-OVA-IEC lowered IL12p70 and IL23 in DCs and suppressed IL13 (<i>p</i> < 0.005) in T cells, while enhancing IL17 (<i>p</i> < 0.001) and IL10 (<i>p</i> < 0.005).These results show that OVA drives Th2- and Th1-type immune responses via activation of IECs in this model. 2′FL and 3FL differentially affect OVA-IEC-driven immune effects. 2′FL boosted overall T-cell OVA-IEC immunity via DC enhancing inflammatory and regulatory responses. 3FL-OVA-IEC-DCs silenced IL13, shifting the balance towards IL17 and IL10.This model demonstrates the contribution of IEC to OVA Th2-type immunity. 2′FL and 3FL modulate the OVA-induced activation in this novel model to study allergic sensitization.

An advanced in vitro human mucosal immune model to predict food sensitizing allergenicity risk: A proof of concept using ovalbumin as model allergen

“…The current data show that ovalbumin can provoke type 2 activation of both IEC as well as DC. Previously we confirmed that OVA-IEC could drive functional type 2 differentiation in DC, but in the latter study IEC were exposed to OVA for 24h before the IEC/moDC coculture (13). The current study shows both OVA-IEC-DC as well as OVA-DC to obtain a type 2 moDC phenotype, but their phenotype differs depending on the presence of IEC which are known to shape the innate immune response.…”

“…Thus the initial presence of IEC during allergen exposure may have facilitated not only the release of type 2 activating mediators but also regulatory factors that suppressed full DC activation in this model. Yet, previous in vitro studies demonstrated a type 2 instructing effect from epithelial cells, which can be due to differences in model conditions ( 11 – 13 ). However, the current study shows a stronger type 2 response to OVA in absence of IEC, while OVA-IEC-DC contribute to enhanced regulatory IL-10 secretion during coculture with T cells as indicator for a more tolerogenic response to the allergen.…”

“…Subsequent coculture of OVA-IEC-DC and OVA-DC with allogenic naïve Th cells demonstrated differential functional polarizing outcomes of these DC. More conventional in vitro allergy models mostly do not include IEC ( 16 , 24 , 25 ), while the presence of IEC is important in the initiation of the allergic response ( 13 , 26 , 27 ). Interestingly, OVA-IEC-DC did not alter type 1 or type 2 related cytokine secretion by T-cells, while OVA-DC were capable of driving Th2 polarization as indicated by enhanced IL13 secretion and an increased percentage of IL13-expressing Th cells.…”

“…However, the current study shows a stronger type 2 response to OVA in absence of IEC, while OVA-IEC-DC contribute to enhanced regulatory IL-10 secretion during coculture with T cells as indicator for a more tolerogenic response to the allergen. Furthermore, in a previous study we investigated the contribution of OVA pre-exposed IEC in type 2 development via instructing moDC ( 13 ). In the current study we use the same OVA source which contains some contamination with endotoxins.…”

“…Recent attempts have aimed to develop sensitizing allergenicity models up till the T cell response ( 11 , 12 ), however the use of murine cells may lack translational value to study food allergy from a human perspective. In a similar approach we recently showed the contribution of epithelial cells in driving the first steps of allergic sensitization ( 13 ). In the current manuscript, we also used the common food allergen ovalbumin, the most abundant protein in hen’s eggs ( 14 ), to develop a novel predictive and advanced in vitro human mucosal immune model.…”