Herein, we will review the evidence for the binding of fungal derived (1 3)-b-D-glucans to receptors on human macrophage U937 and neutrophil HL-60 cell lines. We have observed binding of yeast derived (1 3)-b-D-glucan to multiple receptors in each cell line. We have also demonstrated that the receptor(s) is specific for (1 3)-b-D-glucan binding, since it will not recognize mannan or dextran, non-b linked polymers. In addition, the receptor(s) show dramatic differences in binding affinity between (1 3)-b-D-glucans. Scleroglucan a triple helical polymer binds with high affinity (IC₅₀ = 23 nM) , while single helical glucans, such as glucan phosphate and laminarin, are bound with lower affinity (IC₅₀ = 24 mM). Our data indicate that human macrophage and neutrophil cell lines have multiple receptors which specifically bind (1 3)-b-D-glucans and that the triple helical conformation, molecular weight and polymer charge may be important determinants in receptor ligand interaction.