Resistance of parvalbumin to gastrointestinal digestion is required for profound and long‐lasting prophylactic oral tolerance

Abstract

Background Early introduction of food allergens into children's diet is considered as a strategy for the prevention of food allergy. The major fish allergen parvalbumin exhibits high stability against gastrointestinal digestion. We investigated whether resistance of carp parvalbumin to digestion affects oral tolerance induction. Methods Natural Cyp c 1, nCyp c 1, and a gastrointestinal digestion‐sensitive recombinant Cyp c 1 mutant, mCyp c 1, were analyzed for their ability to induce oral tolerance in a murine model. Both antigens were compared by gel filtration, circular dichroism measurement, in vitro digestion, and splenocyte proliferation assays using synthetic Cyp c 1‐derived peptides. BALB/c mice were fed once with high doses of nCyp c 1 or mCyp c 1, before sensitization to nCyp c 1. Immunological tolerance was studied by measuring Cyp c 1‐specific antibodies and cellular responses by ELISA, basophil activation, splenocyte proliferations, and intragastric allergen challenge. Results Wild‐type and mCyp c 1 showed the same physicochemical properties and shared the same major T‐cell epitope. However, mCyp c 1 was more sensitive to enzymatic digestion in vitro than nCyp c 1. A single high‐dose oral administration of nCyp c 1 but not of mCyp c 1 induced long‐term oral tolerance, characterized by lack of parvalbumin‐specific antibody and cellular responses. Moreover, mCyp c 1‐fed mice, but not nCyp c 1‐fed mice developed allergic symptoms upon challenge with nCyp c 1. Conclusion Sensitivity to digestion in the gastrointestinal tract influences the capacity of an allergen to induce prophylactic oral tolerance.

Novel vaccines for allergen-specific immunotherapy

“…In this context, approaches, such as prophylactic oral tolerance induction with T-cell epitope-containing peptides have been reconsidered for allergen-specific prevention [ 72 ]. A recent study performed in murine model of fish allergy showed that prophylactic feeding with the major fish allergen parvalbumin induced tolerance point to a T-cell-mediated, tolerogenic effect [ 73 ▪ ]. However, further studies will be necessary to investigate if such an effect can also be obtained with synthetic allergen-derived peptides.…”

Advances and novel developments in molecular allergology

“…When the calcium-binding residues of carp parvalbumin Cyp c 1 were mutated, the structural stability of the allergen, hence its resistance to digestion, were drastically affected. 39 Unlike the natural allergen, the mutated form could not induce prophylactic tolerance in a mouse model of fish allergy. 39 Interestingly, proteins with allergenic activity were found to be relatively more abundant and stable than nonallergens in extracts from birch pollen, timothy grass, ragweed pollen, and German cockroach.…”

“…39 Unlike the natural allergen, the mutated form could not induce prophylactic tolerance in a mouse model of fish allergy. 39 Interestingly, proteins with allergenic activity were found to be relatively more abundant and stable than nonallergens in extracts from birch pollen, timothy grass, ragweed pollen, and German cockroach. 40…”

“…Sensitivity of an allergen to gastro‐intestinal digestion also shapes its ability to induce oral tolerance. When the calcium‐binding residues of carp parvalbumin Cyp c 1 were mutated, the structural stability of the allergen, hence its resistance to digestion, were drastically affected 39 . Unlike the natural allergen, the mutated form could not induce prophylactic tolerance in a mouse model of fish allergy.…”

Fish Allergy Management: From Component-Resolved Diagnosis to Unmet Diagnostic Needs

“…The apo-protein has a lower IgE-binding capacity as compared with the ion-charged molecule, concluding that important IgE epitopes are located in the ion-binding regions [47]. Parvalbumin mutants with modified EF-hand motifs feature reduced IgE-binding capacity and low stability to gastrointestinal digestion [48,49]. Otherwise, parvalbumin has great molecular stability under thermal, chemical and proteolytic conditions.…”