Measurement of Horse Allergens Equ c 1 and Equ c 2: A Comparison among Breeds

Abstract

<b><i>Introduction:</i></b> Horse allergens are less studied than allergens from other furry animals and these allergens must be evaluated to understand the complexity of allergy to horses. The aims of this study were to develop assays for the horse allergens Equ c 1 and Equ c 2 in dander and saliva and to determine their levels in ten horse breeds. The study also included a comparison of these findings with previous results on the levels of Equ c 4 performed on the same study population. <b><i>Method:</i></b> The study population included 170 horses from 10 horse breeds including American Curly and Russian Bashkir horse, which have been suggested to be hypoallergenic. Competitive ELISA assays were developed, with polyclonal antibodies as capture antibodies, for the detection of Equ c 1 and Equ c 2 in dander and saliva samples. <b><i>Results:</i></b> The horse allergens Equ c 1 and Equ c 2 were found in all dander and saliva samples from the ten horse breeds. The GM level (ng/µg protein) of Equ c 1 in dander was 470 (range 129–2,569) and in saliva samples, 40 (range 6–160). The GM level of Equ c 2 in dander was 138 (range 18–1,650) and in saliva samples, 0.8 (range 0.03–17). In dander, there were no significant differences in Equ c 1 and Equ c 2 GM levels between stallions, mares, and geldings. <b><i>Conclusion:</i></b> Our results show high intra- and inter-breed variability. Neither the American Curly horse nor the Russian Bashkir horse, earlier categorized as hypoallergenic breeds, was associated with lower allergen levels of Equ c 1, Equ c 2, or Equ c 4 than the other horse breeds investigated.

Horse allergy: Curly Horses can mediate immune tolerance

“…The study by Zahradnik et al and the studies by Victor et al [56][57][58] found a high diversity of allergen content in horse hair for Equ c 1 and Equ c 4, as well as in the Curly Horses studied. They did not find a Curly Horse-associated mean lower level of allergens in horse hair or release of allergens during grooming of Curly Horses compared to Quarter Horses.…”

Proteomic analysis of horse hair extracts provides no evidence for the existence of a hypoallergenic Curly Horse breed

“…including Curly and Quarter Horses. 15,16 Their results showed high intra-and inter-breed variations as well. No significant differences in allergen contents in horse dander samples between breeds were found.…”

“…So far, studies addressing the topic of hypoallergenic breeds have used antibody‐based techniques to quantify allergens in the dust of homes or the animals' coats, saliva, and urine. “Hypoallergenic” dog and horse breeds were not associated with significantly reduced allergen content 14–16,36,37 …”

“…"Hypoallergenic" dog and horse breeds were not associated with significantly reduced allergen content. [14][15][16]36,37 The material analyzed in the present study was obtained in a larger project where horse dander antigen, Equ c 1, and Equ c 4 levels were previously quantified by ELISA in horse hair extracts of 32 breeds. 14 Allergen concentrations varied strongly in individual horses, but median Equ c 1 levels were 2.6-fold, and Equ c 4 levels were 3.1-fold higher in Curly Horses compared with Quarter Horses.…”

“…Depending on the study, allergen levels of Curly Horses were either similar or significantly higher compared to other horse breeds. [14][15][16] Also, air samples collected during grooming showed no differences in allergen content between Curly Horses and the popular horse breed American Quarter Horse. 14 As these studies relied on antibody-based detection of horse allergens, variations in allergen sequences might not have been detected.…”