Enhancement of the Immunostimulatory Activity of 1,25-Dihydroxyvitamin D3-Differentiated HL60 Cells with an Arabinoxylan from Wheat Bran

We found that a wheat bran arabinoxylan (WBA) activates the phagocytosis of 1,25-dihydroxyvitamin D3-differentiated HL60 cells; however, its mechanism was unknown. Hence, we investigated the molecular mechanism involved in the WBA-induced increase of immunostimulating activity using inhibitors. The results indicated that the WBA-induced increases in phagocytic activity and IL-1β production were inhibited by cathepsin B and caspase-1 inhibitor. Moreover, IL-1β production was inhibited by a phagocytosis inhibitor.