The use of aluminium hydroxide as adjuvant modulates the specific antibody response—A Brown Norway rat study with native and denatured cow's milk allergens

Abstract

There is a need for efficient methods to treat food allergy; however, no immunotherapeutic method has yet been satisfactory due to the high rate of unpredictable severe reactions and the limited efficacy. Therefore, modified versions of food allergens have been suggested as alternatives to the parent proteins for immunotherapy. The aim of the study was to compare the inherent allergenicity of the native and denatured version of the cow's milk proteins β‐lactoglobulin and α‐lactalbumin, and to study the impact of the use of Al(OH)3 as an adjuvant. Brown Norway rats were immunized intraperitoneally with either native or denatured β‐lactoglobulin or α‐lactalbumin, with or without the use of Al(OH)3 as adjuvant. Antibody responses were analysed in various ways by means of different ELISAs. Both the immunogenicity and the sensitizing capacity of the cow's milk allergens were influenced by their globular folding, with the native version being more allergenic than the denatured counterpart. The native folded proteins mainly raised antibodies against conformational epitope, whereas the denatured versions predominantly raised antibodies against linear epitopes. Most interestingly, the study showed that the use of Al(OH)3, besides increasing immunogenicity and sensitizing capacity of the cow's milk allergens, caused a modification of the specificity of the antibodies raised against the native version of the proteins. Adsorption of the native forms of the allergens to Al(OH)3 caused a significant greater proportion of antibodies raised against linear epitopes, stressing that the adsorption induced a partly unfolding of the proteins. This may have implications for IT safety and efficacy.

A Food Matrix Triggers a Similar Allergic Immune Response in BALB/c Mice Sensitized with Native, Denatured, and Digested Ovalbumin

“…In all groups, the IgE responses to both N-OVA and D-OVA were inconsistent, although more robust against N-OVA. In line with these findings, Bøgh et al reported that after IP administration, native and denatured cow’s milk allergens (β-lactoglobulin and α-lactalbumin) triggered different sensitizing capacities, with native allergens sensitizing more effectively than denatured ones [ 17 ]. These results, and the ones reported in the present study, suggest that mice can be IP sensitized to different structural forms of food allergens, and this fact should be considered in the search for an animal model to evaluate the allergenic potential of processed foods.…”

“…Furthermore, it should be highlighted that undetectable IgE levels using ELISA do not mean the absence of sensitization, as in our experience, serum levels of biological markers of an allergic immune response can become evident after an intragastric challenge [ 10 ]. In the present study, we used Al(OH) 3 (Imject Alum) for OVA-sensitization, a systemic adjuvant that enhances the production of both IgG and IgE antibodies [ 17 , 18 ], which can compete for the same OVA epitopes [ 19 ]. In fact, a high ratio of IgG/IgE in serum after IP sensitizations [ 20 , 21 ] as well as the convenience of depleting IgG to accurately assess IgE in serum [ 11 ] were documented.…”

Integrating Widely Targeted Lipidomics and Transcriptomics Unravels Aberrant Lipid Metabolism and Identifies Potential Biomarkers of Food Allergies in Rats

“…The experimental modeling scheme was based on Abril-Gil et al, [23] Madsen et al, [24] and Bøgh et al [25][26][27] with slight modifications. On days 1, 3, and 5 of the experiment, 500 μL saline or 500 μL saline containing 2 mg PP, MP, or SP including 125 μL Imject Alum (40 mg mL −1 , Thermo Fisher Scientific Inc., USA) was injected intraperitoneally into each rat for sensitization.…”