Mechanisms of Wheat Allergenicity in Mice: Comparison of Adjuvant-Free vs.Alum-Adjuvant Models (1)
The genetic modification of wheat may also potentially alter its allergenicity. Despite widespread use, changes in the allergenic potential of various types of novel and altered wheat products are largely unknown, primarily due to the lack of validated in vivo methods of allergenicity assessment.
A significant elicitation of WSIgE was noted. The control group of mice did not show WSIgE responses. Another group of mice was sensitized using an AA method. A significant WSIgE response was noted.
The alum-alone injected control mice did not show WSIgE responses.
A significant elicitation of TIgE was noted. The control group of mice did not show significant TIgE responses. Mice that were sensitized using the AA method also showed a significant elevation of TIgE levels. The alum-alone injected control mice did not show a significant elevation of TIgE levels.
A significant elevation of WSIgG1 was noted in the skin-exposed mice but not in the control group. In the AA model
also, a significant elicitation of WSIgG1 was noted. The alum-alone injected control mice did not show WSIgG1 responses.
The skin-sensitized mice did not show a marked WSIgG2a response in the AF model. However, in the AA model, a significant elicitation of WSIgG2a was noted. The alum-alone injected control mice did not show WSIgG2a responses.
In the AF model, there was a significant increase in the levels of the plasma MMCP-1 protein after the SSWP challenge. In the control group of mice, there was no significant elevation of MMCP-1 protein levels. In the AA model also, there was a significant increase in the levels of the plasma MMCP-1 protein after the SSWP challenge. In the alum-alone injected control group of mice, there was no significant elevation of MMCP-1 protein levels.
In the AF model, the following cytokines showed significant elevations in the allergic mice compared with the control mice: IL-4, IL-5, IL-7, IL-10, IL-12p70, IL-17B, IL-17E (IL-25), IL-17F, IL-20 and IL-23. In the AA model, the injection with alum-alone significantly increased a number of cytokines including the prototypic Th2 cytokine IL-4. Only the following cytokines showed a significant elevation in the allergic mice compared with the alum-alone injected control mice (Table 3): IFN-g (Th1 marker), IL-5 and IL-13 (Th2 markers), IL-2 and IL-21.
In the AF model, the following chemokines showed significant elevations in the allergic mice compared with the control mice: CXCL4 (PF-4), CXCL11 (I-TAC), CCL4 (MIP-1b), CCL5 (RANTES), CCL9 (MIP-1g), CCL11 (eotaxin), CCL19 (MIP-3b) and CCL22 (MDC). Only the following were significantly elevated in the allergic mice compared with the alum-alone injected control mice: CXCL12 (SDF-1a), CXCL13 (BLC), CCL3 (MIP-1a), CCL12 (MCP-5), CCL21 (6Ckine) and XCL1 (Lymphotatin).
In the AF model, E-Selectin, VCAM-1, MadCAM-1, P-Cadherin and E-Cadherin were all significantly elevated in the allergic mice compared with the control mice. In the AA model, the injection with alum-alone significantly increased the levels of VCAM-1 and P-Cadherin, thus making them not useful as markers for the assessment of the intrinsic allergenicity of SSWP. In the AA model, the allergic mice showed significant elevations of only the P-Selectin and MadCAM-1 proteins.
In the AF model, significantly increased levels of C5a, CRP, CD40, CD40L and CTLA4 were noted in the allergic mice compared with the control mice. In the AA model, alum alone significantly increased the levels of C5a, CRP and MBL-2, thus making them not useful in the analysis of the intrinsic allergenicity of AAWP. In the AA model, the allergic mice showed significant elevations of only CD40 and CD40L proteins.
Different sets of cytokines were overexpressed in these two types of models indicating a marked difference in the cytokine-mediated mechanisms of wheat allergenicity in these two models.
Different sets of chemokines were overexpressed in these two types of models, indicating a marked difference in the chemokine-mediated mechanisms of wheat allergenicity.
Different sets of adhesion molecules were overexpressed in these two types of models, indicating a marked difference in the mechanisms of wheat allergenicity. Different patterns of overexpression in these immune markers in these two types of models, indicating again, a marked difference in the mechanisms of wheat allergenicity.
MMCP-1 is a robust and specific in vivo immune marker that distinguishes IgE antibody-mediated anaphylaxis from that of IgG1 antibody-mediated anaphylaxis in mice. Therefore, in recent years, MMCP-1 has been validated as a highly useful in vivo immune marker of the elicitation of IgE-mediated anaphylaxis. The cytokine IL-10 is regarded as a regulatory and anti-inflammatory cytokine in humans and in some animal models. However, IL-10 is essential for Th2-mediated allergic reactions in mice when skin is used as the route for delivering the allergen. In this mouse model of allergy, IL-10 is a promoter of allergic reactions.
Note: Protocol
The Salt-Soluble Wheat Protein Extract (SSWP) was prepared from durum wheat (variety Carpio). Ten grams of flour in 100 mL of 0.5 M NaCl was stirred continuously for 2 h at 20C followed by centrifugation (5000 g, 10 min) at 20C. In the AF method, a group of mice were exposed to SSWP by the transdermal application (1 mg/mouse/application) once a week for 6 weeks.