The influence of different growth media and different isolates of Stachybotrys chartarum on monoclonal antibody (Mab) reactivity

Abstract

potent when few spores are detected in the air. The purpose of this study was to investigate a wide range of genera and examine the differences in allergen released from spores preand post-germination. Allergen expression from spores of Alternaria alternata, Cladosporium herbarum, Aspergillus fumigatus, Botrytis cinerea, Epicoccum nigrum, Exserohilum rostratum, Penicillium chrysogenum, Stemphylium botryosum and Bipolaris spicifera, were detected using immnnoassay techniques (HALOgen assayTM), by use of serum IgE from fungal allergic subjects. Spores were deposited onto protein binding membranes direct from culture. To germinate spores, samples were incubated in high humidity at room temperature for 48 hours. Ungerminated and germinated samples were then laminated with an adhesive film and immunostained by the Halogen assay. The samples were examined by light microscopy and positive counts (haloed particles) were expressed as percentages of total spores. The percentage of ungerminated spores releasing allergen was variable across the genera, with Alternaria alternata (67.7_+2.3), Epicoccum nigrum (92-+0.6), Stemphylium botryosum (87.3-+2.4) and Cladosporium herbarum (40.8-+7.4) recording the highest percentages. The remaining species eluted allergen from fewer spores (< 15%) with Penicillium chrysogenum (0-+0) recording the least. Across all genera, all spores that germinated exhibited allergen elution along their hyphae. Post-germination, six of the nine genera showed a significant increase in the percent of spores eluting allergen (p<0.0001). Localization of allergen along the hyphae appeared to vary with the genera, such that Exserohilum rostratum and Stemphylium botryosum eluted allergen from hyphal tips and septal junctions, whereas Alternaria alternata, Aspergillus fumigatus, Penicillium chrysogenum and Epicoccum nigrum eluted allergen along the entire length of their hyphae. This study further supports the hypothesis that greater amounts of allergen may be released upon germination of fungal spores. This is the first study to identify the nature of allergen release from spores and hyphae of these genera. Further studies are required to identify if this phenomenon occurs in the respiratory tract, potentially leading to allergic reactions.