Dectin-1, a specific pattern recognition receptor for beta-1,31 beta-1,6-glucans, is expressed mainly on phagocytes. Human dectin-1 (hDectin-1) and mouse dectin-1 (mDectin-1) were separately expressed on HEK293 cell surfaces for examination of the binding abilities of a synthetic particulate beta-glucan (p beta G), a product extracted from Saccharomyces cerevisiae in this study. The binding of zymosan-FITC to hDectin-1 and mDectin-1 was inhibited by NZ at similar concentrations for 50% inhibition of binding (IC50). However, the kinetics of the time course and dose response to zymosan stimulation observed for U937 and J774A.1 differed. Superoxide anion production was increased in U937 but reduced in J774A.1 when cells were treated with p beta G, zymosan, or laminarin, whereas ovalbumin endocytosis was enhanced in U937 and J774A.J treated either with p beta G, zymosan, laminarin, or barley-glucan. These results indicate that the binding affinity of p beta G to hDectin-1 is similar to the binding affinity to mDectin-1, and that stimulation by p beta G as well as various forms of beta-1,3-glucans on U937 and J774A.1 resulted in upregulation of cell activity and ovalbumin endocytosis. Additionally, other coreceptors on U937 and J774A.1 may be involved in directing different responses to superoxide anion production in these two types of cells. These results will likely contribute to further investigations on identifying the biological forms of beta-glucans capable of binding its specific receptor as the effective immunomodulators. (C) 2010 American Institute of Chemical Engineers Biotechnol. Prog., 26: 1391-1399, 2010