Binding of an Immunomodulator to the Human (1 → 3)-β-D-Glucan Monocyte/Macrophage Receptor
Document Type
Article
Publication Date
12-1-1997
Description
Glucans are fungal and bacterial derived glucose polymers. Glucans modulate immune function via macrophage modulation. A specific (1 → 3)-β-D-glucan receptor has been reported on monocytes/macrophages and their precursors. We studied the effect of different reagents on binding of a water soluble glucan to the human macrophage receptor. We investigated the effect of EGTA, EDTA, dexamethasone, colchicine, cytochalasin D and 2,4-dinitrophenol, on glucan binding to U937 cells, a human promonocytic cell line. Cells were incubated for 90 min with 3H-(1-3)-β-D-glucan phosphate (5-30 μg/well) in the presence of media or dinitrophenol ( 1 mM), EGTA (5 mM, 9.58 mM), EDTA (1, 5, 10 mM) dexamethasone (20, 200, 1000, 2000 nM), colchicine (50 mM) or cytochalasin D. We found that dinitrophenol, dexamethasone, EGTA and cytochalasin D did not affect binding. A 60-70% reduction in binding was seen at 5 and 10 mM EDTA. Colchicine, a microtubule inhibitor, suppressed binding by ∼50 %. We conclude that binding of (1-3)-β-D-glucan phosphate to its receptor is not dependent upon calcium. However, other divalent cations (Mg++, Mn++) may affect binding. The colchicine and cytochalasin D data indicate that microtubules, but not microfilaments, are involved in the binding of glucan to the human macrophage glucan receptor.
Citation Information
Raptis, J.; Müller, A.; Rice, P. J.; Kalbfleisch, J. H.; Kelley, J.; Browder, W.; and Williams, D. L.. 1997. Binding of an Immunomodulator to the Human (1 → 3)-β-D-Glucan Monocyte/Macrophage Receptor. FASEB Journal. Vol.11(3). ISSN: 0892-6638