Recombinant Aspergillus fumigatus allergen I/a (rAsp f I/a) in the diagnosis of Aspergillus related diseases

The allergenic activity and clinical impact of individual IgE-antibody binding molecules from indoor allergen sources

A large number of allergens have been discovered but we know little about their potential to induce inflammation (allergenic activity) and symptoms. Nowadays, the clinical importance of allergens is determined by the frequency and intensity of their IgE antibody binding (allergenicity). This is a rather limited parameter considering the development of experimental allergology in the last 20 years and the criteria that support personalized medicine. Now it is known that some allergens, in addition to their IgE antibody binding properties, can induce inflammation through non IgE mediated pathways, which can increase their allergenic activity. There are several ways to evaluate the allergenic activity, among them the provocation tests, the demonstration of non-IgE mediated pathways of inflammation, case control studies of IgE-binding frequencies, and animal models of respiratory allergy. In this review we have explored the current status of basic and clinical research on allergenic activity of indoor allergens and confirm that, for most of them, this important property has not been investigated. However, during recent years important advances have been made in the field, and we conclude that for at least the following, allergenic activity has been demonstrated: Der p 1, Der p 2, Der p 5 and Blo t 5 from HDMs; Per a 10 from P. americana; Asp f 1, Asp f 2, Asp f 3, Asp f 4 and Asp f 6 from A. fumigatus; Mala s 8 and Mala s 13 from M. sympodialis; Alt a 1 from A. alternata; Pen c 13 from P. chrysogenum; Fel d 1 from cats; Can f 1, Can f 2, Can f 3, Can f 4 and Can f 5 from dogs; Mus m 1 from mice and Bos d 2 from cows. Defining the allergenic activity of other indoor IgE antibody binding molecules is necessary for a precision-medicine-oriented management of allergic diseases.

Recombinant expression and antigenic properties of a 32-kilodalton extracellular alkaline protease, representing a possible virulence factor from Aspergillus fumigatus

A 32-kDa nonglycosylated alkaline protease (EC 3.4.1.14) with elastolytic activity, secreted by the opportunistic pathogen Aspergillus fumigatus ATCC 42202, is suggested to be a virulence factor of this fungus. The enzyme is a serine protease of the subtilisin family, and its cDNA nucleotide sequence has recently been reported. We have cloned the cDNA encoding the mature protease into a high-level Escherichia coli expression plasmid and produced the recombinant protease as a fusion protein with a six-adjacent-histidine affinity tag at the carboxy terminus. Subsequently, the recombinant protease was purified to homogeneity, with affinity chromatography yielding 30 to 40 mg of recombinant protease per liter of E. coli culture. Refolded recombinant protease, in comparison with native protease, demonstrated weak enzymatic activity but similar immunochemical characteristics as analyzed by antigen-specific enzyme-linked immunosorbent assay (ELISA), competition ELISA, and immunoblotting assays. To assess the allergenic potential of the protease, sera from patients with allergic bronchopulmonary aspergillosis and sera from healthy control individuals were analyzed by ELISA and immunoblotting techniques. Sera from patients with allergic bronchopulmonary aspergillosis did not have protease-specific immunoglobulin E (IgE) antibodies and, remarkably, did not show significantly elevated protease-specific IgG antibody levels compared with those in sera from healthy control individuals. This suggests that the alkaline protease from A. fumigatus does not elicit IgE antibodies and has weak immunogenicity, a property which may explain fungus persistence in allergic individuals.