IgE Reactivity of the Dog Lipocalin Allergen Can f 4 and the Development of a Sandwich ELISA for Its Quantification

Abstract

PurposeDivergent results on the IgE reactivity of dog-allergic subjects to Can f 4 have been reported. The aim of this study was to evaluate the significance of Can f 4 in dog allergy and to develop an immunochemical method for measuring Can f 4 content in environmental samples.MethodsWe purified the natural dog allergen Can f 4 from a dog dander extract by monoclonal antibody-based affinity chromatography and generated its variant in a recombinant form. Sixty-three dog-allergic patients and 12 nonallergic control subjects were recruited in the study. The IgE-binding capacity of natural Can f 4 and its recombinant variant was assessed by ELISA, immunoblotting, and skin prick tests (SPT).ResultsEighty-one percent of the dog-allergic patients showed a positive result to the immunoaffinity-purified natural Can f 4 in IgE ELISA, but only 46% in IgE immunoblotting. Respective results with the recombinant Can f 4 variant were 54% and 49%. SPT results reflected those obtained in ELISA and immunoblotting. The overall IgE reactivity of the immunoaffinity-purified natural Can f 4 was found to depend strongly on the integrity of the allergen's conformation. A sandwich ELISA based on monoclonal antibodies was found to be functional for measuring Can f 4 in environmental samples.ConclusionsCan f 4 is a major allergen of dog together with Can f 1 and Can f 5. In combination with other dog allergens, it improves the reliability of allergy tests in dog allergy.

Indoor Allergens and Allergic Respiratory Disease

“…Interestingly, 38 % of dog-allergic patients were monosensitized to Can f 5 [63]. Other relevant dog allergens are the lipocalins Can f 2 and Can f 4 and the cross-reactive dog serum albumin Can f 3, which react with 20–30, 15–50, and 81 % of IgE from dog-allergic patients, respectively [64–67]. …”

Allergens in dog extracts: Implication for diagnosis and treatment

“…Thus, the activity of important allergens may be lost during manufacturing. An indirect proof of the importance of nCan f 4 is the reported prevalence of sensitization of more than 80%, suggesting that sensitization is underestimated when diagnosed with commercially available SPT extracts.…”

“…Can f 4 appears in at least two isoforms . The prevalence of sensitization varies between geographic regions from 46% to 81%, indicating that there might be a difference in reactions to the isoforms . Can f 5 is a prostatic kallikrein homologous to human prostate‐specific antigen (PSA).…”

A critical review on serine protease: Key immune manipulator and pathology mediator

“…Mice, rat, and dog saliva have kallikrein-type serine proteases. 108,109 While vertebrates have serine proteases with higher identity with that of human, they are less provocative yet they act as the carriers of lethal pathogens such as leptospires in rats, 110 Bartonella bacteria in cats, and Lyssavirus in dogs, 111 among others.…”