Enzyme-Linked Immunosorbent Assay Specific for (1→6) Branched, (1→3)-β-d-Glucan Detection in Environmental Samples

(1→3)-β-d-Glucans have been recognized as a potential causative agent responsible for bioaerosol-induced respiratory symptoms observed in both indoor and occupational environments. A specific enzyme immunoassay was developed to quantify (1→6) branched, (1→3)-β-d-glucans in environmental samples. The assay was based on the use of a high-affinity receptor (galactosyl ceramide) specific for (1→3)-β-d-glucans as a capture reagent and a monoclonal antibody specific for fungal cell wall β-d-glucans as a detector reagent. The assay was highly specific for (1→6) branched, (1→3)-β-d-glucans (such as that from Saccharomyces cerevisiae) and did not show any response at 200 ng/ml to curdlan, laminarin, pustulan, dextran, mannan, carboxymethyl cellulose, and endotoxins. The detection level was 0.8 ng/ml for baker's yeast glucan and Betafectin. A coefficient of variation of 7.8% was obtained for (1→3)-β-d-glucans in house dust samples. Metal working fluids spiked with (1→3)-β-d-glucans inhibited the glucan assay. Because the assay is specific for (1→6) branched, (1→3)-β-d-glucans and is sensitive and reproducible, it will be useful for the investigation of health effects from exposure to this class of biologically active molecules.