Allergens of horse epithelium. I. Physicochemical and immunochemical characterization of five different horse epithelium raw materials used for allergen extract preparation

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.