TISSUE LOCALIZATION OF BOVINE DANDER ALLERGEN BOS-D-2

Background: Domestic mammals are important sources of indoor allergens . However, the origin at the tissue level and the biologic function of mammalian allergens are largely unknowm. Objective: The aim of this s tudy was to localize the source of the major bovine dander allergen, B os d 2, in bovine tissues. Methods: Samples from several organs were t ested for the presence of mRNA encoding Bos d 2 and Bos d 2 protein by using the reverse transcriptase polymerase chain reaction and immunoh istochemical staining, respectively. Results: Skin proved to be the on ly tissue where mRNA encoding Bos d 2 was detected. This observation w as confirmed by immunohistochemistry with a monoclonal anti-Bos d 2 an tibody as the primary antibody. In the skin sections, Bos d 2 was foun d in the secretory cells of apocrine sweat glands and the basement mem branes of the epithelium and hair follicles. Bos d 2 belongs to the fa mily of lipocalins comprising a number of pheromone carrier proteins t hat are present, for example, in the secretions of the apocrine sweat glands. Conclusion: Together with earlier data, our findings suggest t hat Bos d 2 is produced in sweat glands and transported to the skin su rface as a carrier of the pheromone ligand. Because dander allergens o f a number of mammalian species are lipocalins, the common biologic fu nction of being pheromone carriers seems to be a common feature of an important group of aeroallergens.