Epitope mapping studies performed with overlapping peptides of Cyp c 1 identified peptide 5 comprising amino acids 61 to 80 in the Cyp c 1 sequence as a major T-cell epitope that may be useful information for approaches studying T-cell epitope-targeting strategies in the murine model

Epitope mapping studies performed with overlapping peptides of Cyp c 1 identified peptide 5 comprising amino acids 61 to 80 in the Cyp c 1 sequence as a major T-cell epitope that may be useful information for approaches studying T-cell epitope-targeting strategies in the murine model. rabbit sera were tested for their ability to inhibit IgE recognition of Cyp c 1, Cyp c 1Cspecific basophil degranulation, and Cyp c 1Cinduced allergic symptoms in the mouse model. Results A mouse model of fish allergy mimicking human disease regarding IgE epitope recognition and symptoms as close as you possibly can was established. Administration of antisera generated in mice and rabbits by immunization with a hypoallergenic Cyp c 1 mutant inhibited IgE binding to Cyp c 1, Cyp c 1Cinduced basophil degranulation, and allergic symptoms caused by allergen challenge in sensitized mice. Conclusions Antibodies induced by immunization with a hypoallergenic Cyp c 1 mutant protect against allergic reactions in a murine model of fish allergy. Keywords: Blocking antibodies, fish allergy, hypoallergenic parvalbumin mutant, specific immunotherapy Fish represents an important elicitor of food allergy causing severe allergic reactions that are often life-threatening.1 The prevalence of fish allergy ranges from 0.2% to 10% depending on the population and is particularly NS 11021 high in countries with high fish consumption.2,3 Whereas many food allergies are diseases of early childhood that are often outgrown, allergy to fish often persists through adulthood.4 Allergen-specific immunotherapy (SIT) is highly effective for respiratory forms of allergy and insect venom allergy.5 There are also several approaches pursued for SIT of food allergy including oral, sublingual, epicutaneous, and subcutaneous administration of allergens or modified allergens.6,7 A recent review of clinical studies in oral SIT for food allergy indicated that outcomes of treatment may be different for different allergens.8 Despite the variability of SIT regarding clinical outcome for different food allergens, studies performed for different allergens suggest that besides alterations at the cellular level, an induction of allergen-specific IgG antibodies may be important for the success of SIT in food allergy.9,10 At present, SIT is not available for fish allergy although parvalbumin, a protein containing calcium-binding sites, has NS 11021 been characterized as a cross-reactive allergen in many fish species and recombinant fish parvalbumins mimicking the immunological properties of the corresponding natural allergens have been produced.4,11 Based on the observation that this depletion of calcium leads to a substantial loss of IgE reactivity of fish parvalbumins,12 we have developed a recombinantly expressed hypoallergenic variant of the fish allergen Cyp c 1 from carp by mutation of the calcium-binding sites in the protein as a candidate molecule for SIT of fish allergy.13 We recently also demonstrated that this strategy of introducing point mutations into the calcium-binding sites of fish parvalbumins can be used to reduce the allergenic activity of the major allergens from a variety of fish species.14 In this study we aimed to establish a murine model of fish allergy that mimics fish allergy in patients as closely as you possibly can. For this purpose, mice were orally sensitized with the major fish allergen Cyp c 1 and the development, epitope-specificity, and biological activity of specific IgE antibodies were Rabbit Polyclonal to EXO1 determined by ELISA, basophil degranulation experiments as well as by provocation testing and assessment of allergic symptoms. To investigate whether IgG antibodies induced by immunization with the recombinant Cyp c 1 mutant (ie, mCyp c 1) can protect against fish allergy, we performed passive immunization of mice who are allergic to fish with mCyp c 1Cspecific rabbit and mouse antisera before oral provocation. The results NS 11021 obtained demonstrate that mCyp c 1Cspecific antibodies can protect against fish allergy NS 11021 and thus indicate that blocking antibodies might represent a major mechanism in SIT with mCyp c 1. Methods Recombinant allergens, synthetic peptides Recombinant wildtype Cyp c 1 (rCyp c 1) and recombinant Phl NS 11021 p 1 (rPhl p 1) were obtained from Biomay AG (Vienna, Austria). A recombinant grass pollen hypoallergen (hP62) consisting of Phl p 2C and Phl p 6Cderived fragments was purified as described.