Competitive receptor binding assay for detecting beta-glucans

A method for detecting a beta-glucan which comprises the steps of:

• (a) providing a test mixture comprising:
• a test cell line that stably expresses human dectin-1 molecule on the cell surface and does not express other glucan receptors, wherein the test cell line is derived from a kidney and attached to the surface of a carrier,
• a sample, and
• a marker beta-glucan that specifically binds to human dectin-1 molecule, wherein
• the marker beta-glucan comprises a detectable molecule;
• (b) contacting the sample and a specific amount of the marker beta-glucan in a test mixture under conditions that allow a complex between the marker beta-glucan or beta-glucan (if any present) and dectin-1 to form;
• (c) contacting the specific amount of the marker beta-glucan with the test cell line in a reference mixture under conditions that allow a complex between the market beta-glucan and dectin-1 to form;
• (d) removing the sample and the marker beta-glucan which do not form a complex with the test cell line in the test mixture in (b) and the reference mixture in (c);
• (e) detecting the amounts of the bound marker beta-glucan in the test mixture and the reference mixture;
• and
• (f) comparing the amount of the marker beta-glucan in the test mixture and that in the reference mixture, wherein the sample is identified to contain the beta-glucan having immunomodulatory activity in a human cell when the amount of the bound marker beta-glucan in the test mixture is less than that in the reference mixture.