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