Structural effects of sulfated polysaccharides from Codium fragile on NK cell activation and cytotoxicity

The effects of sulfates and proteins of the sulfated polysaccharide-F-2 (SP-F-2) from Codium fragile on the NM cell activation and cytotoxicity were systematically investigated. The SP-F-2 treatment significantly increased both NM cell proliferation (129%/100 mu g/mL) and their potent cytotoxic effects against HeLa cells (46%). The SF-F-2 treatment appeared to enhance NK cell activation through the expression of the activating receptor, NKp30; the secretion of the cytokine, IFN-gamma and the release of the lysing proteins, perforin and granzyme-B. However, the treatment of the SP-F-2 derivatives, deproteinated and desulfatedF(2) (DP-F-2 and DS-F-2), markedly lowered the mRNA expression levels of IFN-gamma, granzyme-B, hiMp30 and FasL, suggesting that the proteins and sulfates were essential for the interaction between the SP-F-2 and NK cells. The antibody neutralization test revealed that CR3 might be a critical receptor involved in SF-F-2 NK cell activation. (C) 2017 Elsevier B.V. All rights reserved.