beta-Glucans are heterogeneous groups of glucose polymers found in the cell walls of fungi, plants and some bacteria. Our previous report showed that a novel beta-1,3/1,6-glucan produced from Paenibacillus (P.) polymyxa JB115 can induce nitric oxide (NO) production in RAW264.7 cells. In the present study, the P-glucan significantly increased luciferase activity in cells transfected with NF kappa B or AP1, but not STAT1, reporter vector DNA, which contain their binding promoter site. All specific NF kappa B and MAPKs pathway inhibitors (pyrrolidine dithiocarbamate, AG490, U0126, SB203580 and SP600125) remarkably attenuated NO production induced by the beta-glucan. Furthermore, Western blot analysis revealed that the stimulation of Raw264.7 cells by beta-glucan induced phosphorylation of I kappa B and the consequent translocation of NF kappa B into the nucleus. Meanwhile, phosphorylation of ERK1/2, JNK/SAPK and p38 MAPKs in cytoplasm were also confirmed. All these results indicated that beta-glucan from P. polymyxa JB115 activates macrophages through MAPKs and NF kappa B signaling pathway. (C) 2009 Elsevier Inc. All rights reserved.