Impairing oral tolerance promotes allergy and anaphylaxis: A new murine food allergy model

Antigen-driven anaphylaxis and mast cell activation in SEB/OVA-sensitized mice. After sensitization, mice received a bolus dose of 5 mg of OVA by mouth. A, Symptom scores elicited in CT-driven or SEB-driven sensitization were determined. B, SEB/OVA-sensitized mice responded to OVA but not to an irrelevant antigen, BSA. C, Plasma histamine levels were determined 60 minutes after antigen challenge. D, Numbers and granulation status of mast cells in ear skin were determined by means of histologic analysis. E, A representative section showing pinacyanol erythrosinate staining on jejunum tissue from an SEB/OVA mouse after challenge is shown. Mast cells are stained with a deep blue/purple color. F, Hematoxylin and eosin staining of jejunum, illustrating vasodilation. G, Blood pressure was measured in OVA/SEB-treated mice to determine systemic responses immediately after antigen challenge with a Coda 1 noninvasive blood pressure system. In Fig 1, C and D, data represent the means ± SEMs (n = 6-12). ^∗P < .05 and ^∗∗P < .01, Student t test.

SEB-driven sensitization promotes increased eosinophilia, whereas CT does not. Peripheral blood eosinophil numbers were determined in treated mice. A, Peripheral blood eosinophils were increased in SEB/OVA-treated mice but not in CT/OVA-treated mice. B, Eosinophilia correlated with the amount of SEB administered during sensitization. C, Representative histology of tissue stained with hematoxylin and eosin demonstrating a robust eosinophilic infiltration into the jejunum tissues. Black arrows indicate eosinophils. ^∗P < .05 and ^∗∗P < .01, Student t test (n = 6-12).

A T_H2-skewed antigen-dependent cytokine profile develops after SEB-driven sensitization. Splenocytes from mice previously sensitized with SEB alone, OVA alone, or SEB/OVA were stimulated for 48 hours in the presence of 100 μg of OVA or with plate-bound anti-mouse CD3 (1 μg/mL). A, Cytokine levels in the supernatants were determined by using the cytometric bead assay. Gene expression levels were determined for T_H1/T_H2 (B) and Treg cell–associated (C) mediators. ^∗P < .05 and ^∗∗P < .01, Student t test (n = 5-6). NS, No significant difference.

SEB promotes allergic responses to peanut at a low dose but not at a high dose. Responses to oral administration of 100 μg of WPE (WPElow) or 1 mg of WPE (WPEhigh) ± 10 μg of SEB were determined. Symptom scoring in response to challenge with 5 mg of WPE (A), peripheral blood eosinophilia (B), and WPE-specific IgE levels (C) was determined. Finally, in vitro cytokines on stimulation of splenocytes with 1 mg of WPE or anti-mouse CD3 (1 μg/mL) for 48 hours were studied. IL-4 (D), IL-5 (E), and IFN-γ (F) levels are shown. ^∗P < .05 and ^∗∗P < .01, Student t test (n = 5 per group).

T-cell receptor repertoire use after oral SEB exposure. The percentage of each Vβ subset of T cells was determined by using flow cytometry on spleen cells. Data represent the average percentage of Vβ subsets for the entire CD4⁺ T-cell population. ^∗∗P < .01, Student t test (n = 5 per group).

Core temperatureresponses after antigen challenge. Rectal temperature was measured in WPE/SEB-treated mice to determine systemic responses immediately after antigen challenge. Rectal temperatures were measured concurrently in 7 animals by using an automated PhysioTemp mouse rectal temperature system (PhysioTemp Instruments, Inc, Clifton, NJ) and shown as a change in baseline for each individual mouse, and these were not significantly different (36.7°C ± 0.4°C for control animals and 36.2°C ± 0.4°C for sensitized mice).

SEB promotes allergic responses to peanut in C57BL/6J mice. Responses to oral administration of 100 μg of WPE (WPElow) or 1 mg of WPE (WPEhigh) ± 10 μg of SEB were determined. Symptom scoring in response to challenge with 5 mg of WPE (A) and peripheral blood eosinophilia (B) are shown. ^∗∗P < .01, Student t test.