Comparison of the Interleukin-1β-Inducing Potency of Allergenic Spores from Higher Fungi (Basidiomycetes) in a Cryopreserved Human Whole Blood System

Abstract

Background: Spores from basidiomycete fungi (basidiospores) are highly prevalent in the atmosphere of urban and rural settings. Studies have confirmed their potential to affect human health as allergens. Less is known about their potential to serve as stimuli of the innate immune system and induce proinflammatory reactions. Methods: In this study, we evaluated the proinflammatory potential of spores from 11 allergenic basidiomycete species (gilled: Pleurotus ostreatus,Oudemansiella radicata,Armillaria tabescens,Coprinus micaceus,Pluteus cervinus, and Chlorophyllum molybdites, and nongilled: Pisolithus arhizus,Merulius tremellosus,Calvatia cyathiformis,Lycoperdon pyriforme, andBoletus bicolor) based on their potency to induce the release of the proinflammatory cytokine interleukin (IL)-1β in a cryopreserved human whole blood system. In addition, the roles of morphological features of the spores (surface area, shape, and pigmentation) were examined for their role in the IL-1β-including potency of spores. Peripheral blood from healthy volunteers was collected, pooled, and cryopreserved. After stimulating the cryopreserved pooled blood with 10⁶ to 10³ basidiospores/ml, the concentration of IL-1β in culture supernatants was determined with ELISA. Results: Basidiospores manifested concentration-dependent IL-1β-inducing potency, which was more marked among basidiospores from gilled basidiomycetes. At higher concentrations of basidiospores, the IL-1β-inducing potency could be differentiated in the cryopreserved human whole blood system. Morphological features did not correlate with the IL-1β-inducing potency of the basidiospores, suggesting that nonmorphological properties modulate the IL-1β-inducing potency. Conclusion: Our data provide evidence of the proinflammatory potential of basidiospores, and the utility of cryopreserved human whole blood as a human-based in vitro system to study the immune reactivity of allergenic basidiospores.

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