Dusting the sugar fingerprint: C-type lectin signaling in adaptive immunity.

Pathogen recognition by dendritic cells (DCs) is central to the induction of adaptive immunity. Pattern recognition receptors (PRRs) on DCs interact with pathogens, leading to signaling events that dictate adaptive immune responses. It is becoming clear that C-type lectins are important PRRs that recognize carbohydrate structures. Most pathogens express carbohydrate structures on their surface and these function as a so-called sugar fingerprint that are recognized by specific C-type lectins. Triggering of C-type lectin induces signaling cascades that initiate or modulate specific cytokine responses and therefore tailor T cell polarization to the pathogens. Here we will discuss our current understanding of the innate signaling pathways induced by C-type lectins DC-SIGN and dectin-1 in humans and how these pathways shape adaptive immunity.