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

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 Ca(2+)-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.