Human Dendritic Cells Activated via Dectin-1 Are Efficient at Priming Th17, Cytotoxic CD8 T and B Cell Responses

Background: Dendritic cells capture antigens through PRRs and modulate adaptive immune responses. The type of adaptive immune T cell response generated is dependent upon the type of PRR activated by the microbes. Dectin-1 is a C-type lectin receptor present on dendritic cells. Methodology/Principal Findings: Here we show that selective dectin-1 agonist Curdlan can activate human DCs and induce the secretion of large amounts of IL-23, IL-1 beta, IL-6 and low levels of IL-12p70 as determined by ELISA. The Curdlan-stimulated DCs are efficient at priming naive CD4 cells to differentiate into Th17 and Th1 cells. Furthermore, these CD4 T cells induce differentiation of B cells to secrete IgG and IgA. In addition, Curdlan-stimulated DCs promote the expansion and differentiation of Granzyme and perforin expressing cytotoxic T lymphocyte that display high cytolytic activity against target tumor cells in vitro. Conclusions/Significance: These data demonstrate that DCs stimulated through Dectin-1 can generate efficient Th, CTL and B cell responses and can therefore be used as effective mucosal and systemic adjuvants in humans.