Thermoneutrality Alters Gastrointestinal Antigen Passage Patterning and Predisposes to Oral Antigen Sensitization in Mice.

Food allergy is an emerging epidemic, and the underlying mechanisms are not well defined partly due to the lack of robust adjuvant free experimental models of dietary antigen sensitization. As housing mice at thermoneutrality (Tn) - the temperature of metabolic homeostasis (26-30°C) - has been shown to improve modeling various human diseases involved in inflammation, we tested the impact of Tn housing on an experimental model of food sensitization. Here we demonstrate that WT BALB/c mice housed under standard temperature (18-20°C, Ts) conditions translocated the luminal antigens in the small intestine (SI) across the epithelium via goblet cell antigen passages (GAPs). In contrast, food allergy sensitive Il4raF709 mice housed under standard temperature conditions translocated the luminal antigens in the SI across the epithelium via secretory antigen passages (SAPs). Activation of SI antigen passages and oral challenge of Il4raF709 mice with egg allergens at standard temperature predisposed Il4raF709 mice to develop an anaphylactic reaction. Housing Il4raF709 mice at Tn altered systemic type 2 cytokine, IL-4, and the landscape of SI antigen passage patterning (villus and crypt involvement). Activation of SI antigen passages and oral challenge of Il4raF709 mice with egg antigen under Tn conditions led to the robust induction of egg-specific IgE and development of food-induced mast cell activation and hypovolemic shock. Similarly, Tn housing of WT BALB/c mice altered the cellular patterning of SI antigen passage (GAPs to SAPs). Activation of SI antigen passages and the oral challenge of WT BALB/c mice with egg antigen led to systemic reactivity to egg and mast cell activation. Together these data demonstrate that Tn housing alters antigen passage cellular patterning and landscape, and concurrent oral exposure of egg antigens and SAP activation is sufficient to induce oral antigen sensitization.

Association of Staphylococcus aureus colonization with food allergy occurs independently of eczema severity.

BACKGROUND: Staphylococcus aureus has been implicated in the pathophysiology of eczema, allergic rhinitis, asthma, and food allergy. S aureus is a marker of more severe eczema, which is a risk factor for food sensitization/allergy. Therefore it might be that the association between S aureus and food allergy in eczematous patients is related to eczema severity. OBJECTIVE: We sought to investigate the association of S aureus colonization with specific IgE (sIgE) production to common food allergens and allergies in early childhood independent of eczema severity. We additionally determined the association of S aureus colonization with eczema severity and persistence. METHODS: In Learning Early About Peanut Allergy (LEAP) study participants eczema severity was assessed, and skin/nasal swabs were cultured for S aureus. Sensitization was identified by measuring sIgE levels. Peanut allergy was primarily determined by means of oral food challenge, and persistent egg allergy was primarily determined by using skin prick tests. RESULTS: Skin S aureus colonization was significantly associated with eczema severity across the LEAP study, whereas at 12 and 60 months of age, it was related to subsequent eczema deterioration. Skin S aureus colonization at any time point was associated with increased levels of hen's egg white and peanut sIgE independent of eczema severity. Participants with S aureus were more likely to have persistent egg allergy and peanut allergy at 60 and 72 months of age independent of eczema severity. All but one of the 9 LEAP study consumers with peanut allergy (9/312) were colonized at least once with S aureus. CONCLUSION: S aureus, independent of eczema severity, is associated with food sensitization and allergy and can impair tolerance to foods. This could be an important consideration in future interventions aimed at inducing and maintaining tolerance to food allergens in eczematous infants.