Escherichia coli K5 capsular polysaccharide (K5PS) has been used as starting material to synthesize heparan sulfate (HS) mimetics with various biological properties. This study determined the immunomodulatory activities of K5PS through the sulfation process. The immunomodulatory effects of sulfated K5 polysaccharide derivatives were evaluated in vitro on murine macrophages and lymphocytes. Results indicated that HS mimetics with high sulfation in the O-position stimulated cell proliferation of macrophages and lymphocytes, significantly enhanced cytokine secretion and upregulated the cytotoxicity of NK cells. This study suggests that high sulfation in O-position of HS is required for the immunomodulatory activities.
Keywords: Escherichia coli; Immunomodulatory activity; K5 capsular polysaccharide; Structure–activity correlation; Sulfation.
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