Immunoregulatory activity of an alkaline-precipitated polysaccharide CGP-AP produced by Chaetomium globosum CGMCC 6882

This work characterized the structural features and investigated the immunomodulatory activity of an alkaline-precipitated polysaccharide fraction produced by Chaetomium globosum CGMCC 6882 (CGP-AP) in RAW 264.7 macrophages. The CGP-AP yield was 0.93 ± 0.08 g/L, which contained 98.33% ± 2.04% (w/w) carbohydrate and 1.52% ± 0.26% (w/w) protein. Structural analysis showed that CGP-AP comprised glucose (99.51%) and arabinose (0.49%), its weight (Mw) and number (Mn) average molecular weights were 0.948 and 0.55 kDa, and its polydispersity (Mw/Mn) was 1.724. In vitro immunomodulatory results show that CGP-AP stimulated nitric oxide production and tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and IL-8 secretion via upregulation of the expression levels of related genes in RAW 264.7 macrophages. Meanwhile, CGP-AP upregulated the expression levels of proinflammatory genes (inducible nitric oxide synthase and cyclooxygenase-2 COX-2). Furthermore, CGP-AP improved the antioxidant status of RAW 264.7 cells by increasing antioxidase (superoxide dismutase, catalase, and glutathione peroxidase) levels and enhancing the mRNA expression of nuclear factor erythroid-2 related factor 2. The above results indicate that CGP-AP may be used as a potential immunomodulator in the pharmaceutical industry.