Prompting immunostimulatory activity of curdlan with grafting methoxypolyethylene glycol

The immunostimulatory activity of polysaccharides can improve human immunity, but their activity is low and prompting the activity is a great challenge. Curdlan, is a linear beta-1,3-glucan and has the potential to induce immune responses. However, owing to its tight triple helix structure and insolubility in water, its immunostimulatory activity is weakened. The keyway to promote its immunostimulatory activity is to relax its tight triple helix structure. In this work, methoxypolyethylene glycol (mPEG) was grafted onto curdlan (curdlan-g-mPEG) to unwind its triple helix structure. With its grafting mPEG, the water solubility of curdlan was enhanced. Moreover, with curdlan-g-mPEG treatment, macrophages secreted more tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 and exhibited favorable phagocytosis of bacteria (Staphylococcus aureus and Pseudomonas aeruginosa). These results reveal that curdlan-g-mPEG as an immunostimulant has potential applications in immunology and antibiotics.