Carbohydrate signaling by C-type lectin DC-SIGN affects NF-kappaB activity.

Pathogen recognition is central to the induction of adaptive immunity. Dendritic cells (DCs) express different pattern recognition receptors (PRRs), such as Toll-like receptors and C-type lectins, that sense invading pathogens. Pathogens trigger a specific set of PRRs, leading to activation of intracellular signaling processes that shapes the adaptive immunity. It is becoming clear that cross talk between these signaling routes is crucial for pathogen-tailored immune responses. The C-type lectin DC-SIGN interacts with different mannose-expressing pathogens such as Mycobacterium tuberculosis and HIV-1. Notably, DC-SIGN triggering by these pathogens results in a specific Raf-1-dependent signaling pathway that modulates TLR-induced NF-kappaB activation. Here, we will discuss the various methods that we have used to identify the innate signaling by the C-type lectin DC-SIGN, and how to analyze the consequences on NF-kappaB activation.