Interaction between mannosylated lipoarabinomannan and dendritic cell-specific intercellular adhesion molecule-3 grabbing nonintegrin influences dendritic cells maturation and T cell immunity

► The interaction between manLAM and DC-SIGN was investigated. ► DC-SIGN influenced DCs maturation and downstream immune response. ► Small interfering RNA-expressing lentiviral vectors to specifically knockdown DC-SIGN. ► DC-SIGN knockdown alone in DCs did not affect the maturation or the immunological function. ► Interaction between manLAM and DC-SIGN affects DCs maturation and downstream T cell immunity. The aim of the study was to investigate the interaction between manLAM and DC-SIGN influencing DCs maturation and downstream immune response using small interfering RNA-expressing lentiviral vectors to specifically knockdown DC-SIGN. Our data indicated that DC-SIGN knockdown alone in DCs did not affect the maturation or the immunological function of lipopolysacharide (LPS)-activated DCs. Surface molecules were dramatically down-regulated in DCs primed with manLAM but not in mock control DCs ( P < 0.05). Meanwhile, manLAM enhanced the production of the immunosuppressive cytokine IL-10 in DCs ( P < 0.05). The level of IFN-γ was significantly down-regulated in the supernatants of naive T cells after co-cultured with DCs primed with manLAM ( P < 0.05). We demonstrated that DCs primed with manLAM may partially impair maturation phenotypes and immune response in LPS-activated DCs. However, the alterations of DCs function and downstream immune response caused by manLAM were reversed by the knockdown of DC-SIGN.