Immunodetection and quantification of airborne (1-3)-β-D-glucan-carrying particles with the halogen immunoassay

Fungal cell wall components, such as (1-3)-β-D-glucan, are known to be capable of activating the innate immune system and pose a respiratory health risk in different environments. Mass-based non-viable techniques commonly used for assessment of fungal exposures could be β-D-glucan-specific, but are limited to analysis of liquid extracts. The variable solubility of different β-D-glucans may underestimate β-D-glucan exposure and long sampling times required for mass-based methods make assessing short-term exposures difficult. In this study, we evaluated the utility of the halogen immunoassay (HIA), an immunoblotting technique previously used for allergens, to immunodetect and quantify β-D-glucan-carrying particles (BGCPs). The HIA was able to detect BGCPs without background staining when β-D-glucan standards and air samples collected at a poultry house during short sampling periods were evaluated. The image analysis protocol previously developed by our group for mouse allergen allowed simultaneous immunodetection and quantification of β-D-glucan-containing particles. Our results suggest that the HIA holds promise for quantifying β-D-glucan exposures. To our knowledge, this is the first time in which the HIA was used for non-allergenic compounds of microbial or fungal origins.