Gum Arabic in combination with IFN-γ promotes the M1 polarization in macrophage

Gum Arabic, a mixture of polysaccharide and glycoprotein, is used as an emulsifying stabilizer in the food in-dustry. It might have immunomodulatory effects. We hypothesized that the combination of IFN-gamma and Gum Arabic promotes the production of pro-inflammatory factors in RAW 264.7 cells. Treatment of RAW 264.7 cells with the combination of 3% Gum Arabic and 40 ng/mL IFN-gamma resulted in a drastic increase (320%) in nitric oxide production compared with that induced by IFN-gamma alone. PGE-2 was produced after the cells were treated with 3% Gum Arabic and 40 ng/mL IFN-gamma for 6 h. Gum Arabic and IFN-gamma increased the production of iNOS and COX-2 proteins, and triggered TNF-alpha release. Apart from TNF-alpha, the release of both G-CSF and IL-6 increased by more than 100 times. The release of IL-3, RANTES, and IL-10 increased by more than ten times. Gum Arabic and IFN-gamma also increased the secretion of IL-10, IL-1 alpha, IL-1 beta, IL-13, KC, IL-5, IL-4, IL-12, Eotaxin, IL-9, MCP-1, and ROS. Cytokines associated with M1 polarization of macrophages such as TNF-alpha, IL-1 beta, IL-12, NO, and ROS were induced by Gum Arabic and IFN-gamma. Our findings help to explore the inflammatory reaction caused by Gum Arabic in cosmetics.