Identification of allergens homologous to Alt a 1 fromStemphylium botryosumandUlocladium botrytis

Abstract

Several studies have demonstrated that proteins homologous to the Alt a 1 major allergen of Alternaria alternata are expressed in other members of the Pleosporaceae family. However, since no direct biochemical data have been reported concerning the presence of Alt a 1 allergen homologues capable of binding IgE in the excretion-secretion products of Stemphylium and Ulocladium, our objective was to explore their presence in Stemphylium botryosum and Ulocladium botrytis. S. botryosum and U. botrytis culture filtrate extracts were analyzed by two-dimensional (2D)-electrophoresis and 2D-immunoblotting using polyclonal rabbit antibodies raised against recombinant Alt a 1, as well as five human sera from patients allergic to Alternaria. Cross-reactivity immunoassays were performed by ImmunoCAP inhibition and 2D-immunoblotting inhibition. IgE-binding proteins recognized by the rabbit antiserum raised against Alt a 1, with apparent molecular weights of 17-18 kDa and isoelectric points of 4, were identified as Alt a 1-like proteins. Alt a 1 inhibited IgE-specific binding to the Alt a 1 homologues from S. botryosum and U. botrytis. In conclusion, it was demonstrated that allergens which are homologous to Alt a 1 are expressed in the excretory-secretory materials of the phylogenetically-related species S. botryosum and U. botrytis.

Characterization of fungi in office dust: Comparing results of microbial secondary metabolites, fungal internal transcribed spacer region sequencing, viable culture and other microbial indices

“…alternata in 10.7% of our samples with culturing and 27.3% with DNA sequencing . However, we cannot exclude a possibility that this metabolite might be also produced by other members of the Pleosporales of which we identified a broad diversity using DNA sequencing . Nine metabolites (3‐nitropropionic acid, asperglaucide, chlorocitreorosein, citreorosein, emodin, linamarin, lotaustralin, physcion and tryptophol) could be derived from plants and fungi .…”

Microbial rRNA sequencing analysis of evaporative cooler indoor environments located in the Great Basin Desert region of the United States

“…Alternaria spp., along with other species belonging to the order Pleosporales, including Pleospora and Ulocladium species, produce the major allergen Alt a 1 or a similar homolog, sometimes in greater quantities than A. alternata . 36–38,41 Alt a 1 has been shown to be recognized by human immunoglobulin E in over 80% of Alternaria -sensitized individuals 42,43 and previous studies have demonstrated that 85% of Alternaria -sensitized individuals had positive skin test reactivity to recombinant Alt a 1. 44,45 Individuals in EC environments are likely exposed to Alt a 1, or another homologous allergen, increasing susceptibility to fungal sensitization.…”

“…This is a particularly important risk factor for fungal sensitized populations as fungi placed in this order are among the most frequently encountered fungal sensitizers and contain allergens that are homologous with A. alternata . 36–38 …”

Indoor Exposure to Mould Allergens

“…Recent studies have found homologues of Alt a 1 in the phylogenetically related Stemphylium and Ulocladium species. This suggests that Alt a 1 may not be species-specifi c (47,48). Several other A. alternata allergens have shown significant cross-reactivity with a closely related mould C. herbarum and with non-fungal species (47).…”

“…are also important sources of allergens for mould-allergic patients (33). Cross-reactivity between the most common allergenic moulds has been presented elsewhere (47)(48)(49)(50)(51).…”