Immune-enhancing activities of chondroitin sulfate in murine macrophage RAW 264.7 cells

As a representative sulfated glycosaminoglycan (GAG), chondroitin sulfate (CS) has been reported playing vital roles in the immune response in vivo and in vitro. However, limited information is available about their immune-enhancing activity. This study was to achieve more precise understandings about the immuno-stimulating activity of CS. In in vitro experiments, CS was found to significantly promote the pinocytic, phagocytic activity and ROS production of RAW264.7 cells at the dose range of 100–1000 μg/mL compared with the untreated group (p < 0.05). Further experiments showed that CS could increase the secretion levels of NO, TNF-α, IL-6 and IL-10 via activating the corresponding mRNA expression in macrophages through the toll-like receptor 2 (TLR2). These results indicated that CS could function as an immunostimulator to enhance the immune responses and might be a potential candidate for application in immunological diseases or functional foods.