No abstract

Background In humans, a cross‐reactive clinical allergy has been reported between three chicken and fish meat proteins: beta‐enolase, aldolase A and parvalbumin. Objective To evaluate if IgE cross‐reactivity between chicken and fish also existed in the dog. Animals Sera from dogs with suspected allergic skin disease and with IgE against chicken and fish. Methods and materials Sera were analysed by ELISA and immunoblotting with chicken, white fish (haddock and cod) and salmon extracts. Reciprocal inhibition ELISAs and inhibition immunoblots were then performed. Protein sequencing of bands identified on multiple extracts was determined by mass spectrometry. Results Out of 53 archived canine sera tested by ELISA against chicken, white fish or salmon, 15 (28%), 12 (23%) and 26 (49%), respectively, had elevated IgE against one, two or all three of these extracts. Seven of the triple‐reactive sera were subjected to reciprocal inhibition ELISAs. A >50% inhibition was found between chicken–fish, chicken–salmon and fish–salmon in seven, four and five of seven dogs, respectively. Immunoblotting identified multiple IgE‐binding proteins of identical molecular weights in the three extracts; these were partially to fully cross‐reactive by inhibition immunoblotting. Mass spectrometry identified nine cross‐reactive proteins as: pyruvate kinase, creatine kinase, alpha‐actin, glyceraldehyde‐3‐phosphate dehydrogenase, beta‐enolase, aldolase, malate dehydrogenase, lactate dehydrogenase and triose‐phosphate isomerase 1. All of these have been reported previously as fish, shellfish and/or chicken allergens for humans. Conclusions and clinical importance Whether any of these newly identified IgE cross‐reactive chicken–fish allergens is the cause of clinical allergy needs to be determined in dogs reacting to at least two of these common food sources.

The results suggest that related and potentially cross-reactive foods should be avoided in elimination diets.

BackgroundThe central premise for the commercialization of diets with hydrolyzed ingredients is that the small-sized digested peptides would be unable to crosslink allergen-specific IgE at the surface of tissue mast cells and induce their degranulation. Evidence for the validity of this concept to diagnose food allergies in dogs and cats is limited, however. Our objectives were to study the recognition of standard and variably hydrolyzed poultry extracts by sera from dogs and cats with elevated chicken-specific serum IgE.ResultsForty sera from dogs and 40 from cats with undetectable, low, medium or high serum levels of chicken-specific IgE were tested by ELISA on plates coated with the positive controls chicken, duck and turkey meat extracts and the negative controls beef meat (dogs) or wheat (cats). Plates were also coated with a non-hydrolyzed chicken meal, and mildly- or extensively-hydrolyzed poultry feather extracts. The frequencies of dogs with positive IgE against the various extracts were: chicken meat: 100%, duck and turkey meats: 97%, beef meat: 3%, non-hydrolyzed chicken meal: 73%, mildly-hydrolyzed poultry feathers: 37% and extensively-hydrolyzed poultry feathers: 0%. For cats, these respective percentages were (with wheat replacing beef as a negative control): 100, 84, 97, 7, 7, 0 and 0%. To detect any allergenic cross-reactivity between poultry meat-based and feather hydrolysate-derived extracts, an IgE ELISA inhibition was also done. Ten canine sera with the highest level of anti-poultry IgE in the previous experiment were incubated overnight with a previously optimized 50 μg amount of each of the extracts used above. We performed ELISA on plates coated with chicken, duck or turkey meats with or without inhibitors. The median inhibition percentages after incubation with the non-hydrolyzed chicken meal were ~22%, with the mildly-hydrolyzed poultry feathers: 14–22%, and those with the extensively-hydrolyzed poultry feathers: 5 to 10%; the last inhibition level was similar to that of the beef meat negative control.ConclusionsAltogether, these results suggest that an extensive—but not partial—hydrolyzation of the poultry feather extract is necessary to prevent the recognition of allergenic epitopes by poultry-specific IgE.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-017-1183-4) contains supplementary material, which is available to authorized users.

Levels of serum immunoglobulin E (IgE) specific for the house dust mites (HDMs) Dermatophagoides farinae (DF) and Dermatophagoides pteronyssinus (DP) in 58 cats with clinical signs suggestive of atopic dermatitis (allergic dermatitis cats), 52 cats with no history of allergic or immunological disease (nonallergic cats) and 26 specific pathogen-free (SPF) cats were measured using a monoclonal anti-IgE enzyme-linked immunosorbent assay. Reactivity to both native and reduced HDM allergens was compared. SPF cats had significantly lower levels of HDM-specific serum IgE than cats with allergic dermatitis and nonallergic cats. The difference in levels of HDM-specific IgE in the serum of cats with allergic dermatitis and nonallergic cats was significant for native DF allergen, but not for native DP allergen or reduced HDM allergens. The results suggest that DF in its native form may be a significant allergen in cats with allergic dermatitis. The clinical relevance of these reactions, however, remains to be proven.