Allergens of Horse Epithelium

Abstract

We investigated five horse epithelial allergen extracts prepared from different qualities of raw material by several biochemical and immunochemical methods. Horse serum albumin and horse serum were used to identify serum-related antigens. We found high similarities as well as marked differences between the extracts. There were strong differences in the protein contents, the protein patterns obtained by isoelectric focusing and sodium dodecyl sulfate polyacrylamide gel electrophoresis, the total allergenic activities obtained by radioallergosorbent test inhibition assays and the amounts and numbers of serum-related proteins. The patterns of dander-related allergens in crossed radioimmunoelectrophoresis were similar but showed partly strong differences in allergen concentrations. Allergen compositions determined by blotting methods showed only minor differences between the investigated epithelial extracts. It appears that some of the differences, e.g. the content of serum-related proteins, depend on the way the different raw materials are prepared. Because serum-related extract components are not considered as major allergens, their content should be low in horse epithelial allergen extracts. For this reason whole skin cannot be recommended as starting material for horse epithelium allergen extract preparation.

Comparison of IgE‐binding antigens in horse dander and a mixture of horse hair and skin scrapings

“…(10), Wahn etal. (24), and Franke et al (5) all found horse serum albumin to be of minor allergenic importance. Squire (21) and Ponterius etal.…”

“…Lewenstein et al (10,11) and Markussen et al (12) isolated and partially characterized four allergens from horse hair and dandruff. Recently, Franke et al compared five different horse epithelial allergen extracts by biochemical and immunochemical methods, finding similarities, but also marked differetices, among the extracts (5). The present study was undertaken to compare the protein/glycoprotein content in extracts of horse dander and of horse hair and skin scrapings, to evaluate their ability to act as antigens and allergens by SDS-PAGE and isoelectric focusing (IEF) combined with immunoblotting and CIE/CRIE, and to identify possible allergens in horse dander and in hair and skin scraping extracts which may be of importance for diagnosis of horse allergy.…”

cDNA Cloning and Sequencing Reveal the Major Horse Allergen Equ c1 to Be a Glycoprotein Member of the Lipocalin Superfamily

“…3A). According to the Von Heijne weight matrix method (36), a favored putative signal peptidase cleavage site can be assigned between the Ala 15 and Gln 16 residues, generating a protein beginning with QQEENSDVAI. In contrast, the N-terminal end of the protein initially purified from hair dandruff (SDVAI) would result from a cleavage between Asn 20 and Ser 21 , which is not predicted by Von Heijne's rules.…”

“…In contrast, the N-terminal end of the protein initially purified from hair dandruff (SDVAI) would result from a cleavage between Asn 20 and Ser 21 , which is not predicted by Von Heijne's rules. Equ c1 was purified from saliva, and the microsequencing of its N-terminal peptide revealed a mixture of three sequences, one of them beginning at the predicted Gln 16 , but the others at Glu 18 and Ser 21 , respectively (Fig. 3B).…”

“…The major horse allergen, Equ c1, is a potent allergen responsible for about 80% of anti-horse IgE antibody response in patients who are chronically exposed to horse allergens. Although much work has been carried out on the isolation and identification of the horse allergenic agents responsible for human hypersensitivity response (12)(13)(14)(15)(16), the major horse allergen was only recently purified from hair and dandruff (17). A previous study by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and isoelectric focusing-PAGE showed that Equ c1 appears as a single polypeptide with a relative molecular mass of 21,500 daltons and a pI of 3.9.…”