人可溶性DC-SIGN抑制未成熟树突状细胞吞噬金黄色葡萄球菌

Human soluble dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin inhibits phagocytosis of Staphylococcus aureus by immature dendritic cells

目的研究可溶性DC-SIGN(s DC-SIGN)对未成熟树突状细胞(im DC)吞噬金黄色葡萄球菌(金葡菌)的影响及机制。方法采用流式细胞术分析s DC-SIGN对im DC吞噬金葡菌的影响;ELISA检测s DC-SIGN分别与金葡菌、脂磷壁酸、脂多糖的结合;观察配体甘露聚糖、脂磷壁酸以及抗人DC-SIGN抗体1C6和4H3对s DC-SIGN与金葡菌结合的影响。结果 s DC-SIGN能抑制im DC对金葡菌的吞噬。s DC-SIGN与金葡菌结合,且呈Ca2+依赖性;以浓度依赖方式与脂磷壁酸结合,但不与脂多糖结合;s DC-SIGN与金葡菌的结合可被甘露聚糖、金葡菌磷壁酸和1C6、4H3阻断。结论 s DC-SIGN通过优先与金葡菌表面的一些糖成分结合而影响im DC膜表面DC-SIGN与金葡菌的结合,从而抑制了im DC对金葡菌的吞噬。

Objective To study the effect and mechanism of soluble dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin （sDC-SIGN） on the phagocytosis of Staphylococcus aureus （S. aureus） by immature dendritic cells （imDCs）. Methods Flow cytometry was employed to examine the effect of sDC-SIGN on the phagocytosis of S. aureus by imDCs. Enzyme-linked immunosorbent assay （ELISA） was used to analyze the binging of sDC-SIGN to S. aureus, lipoteichoic acid （LTA） and lipopolysaccharides （LPS） and investigate the effect of the ligands mannan and LTA and anti-DC-SIGN antibodies 1C6 and 4H3 on the binging of sDC-SIGN to S. aureus. Results sDC-SIGN inhibited the phagocytosis of S. aureus by imDCs. sDC-SIGN bound to S. aureus in a Ca2＋-dependent manner. sDC-SIGN concentration-dependently bound to LTA, but not to LTA, and the binging of sDC-SIGN to S. aureus was blocked by mannan, LTA, 1C6 and 4H3. Conclusion sDC-SIGN preferentially binds to the carbohydrate constituents on S. aureus to affect the binding between membrane-bound DC-SIGN and S. aureus, thus suppressing the phagocytosis of S. aureus by imDCs.