The article, entitled “Nanoscale Organization of the Pathogen Receptor DC-SIGN Mapped by Single-Molecule High-Resolution Fluorescence Microscopy” aims to shed light on the organization of DC-SIGN, a pathogen recognition receptor present on dendritic cells.
In large parts of our world infectious diseases have devastating effects on populations and their social and economic development. The immune system is our defence against foreign microorganisms. Dendritic cells (DC) play a crucial role in the immune system by picking up pathogens in the peripheral tissues, migrating to the lymph nodes and subsequently finding and transfer their information to T and B cells. DCs which are among the first cells of the immune system to encounter pathogens, are equipped with a myriad of pathogen recognition- and uptake- receptors. One of those pathogen recognition receptors is the c-type lectin DC-SIGN.
Although significant information on the structure of DC-SIGN is already available, it remains largely obscure how this receptor is capable of efficiently recognising a broad range of pathogens, including the HIV virus. Employing a high resolution optical microscopy technique (NSOM) in the Bionanophotonics laboratory, they have observed that DC-SIGN is organised into distinct nanometre-sized domains. The fact that this has not been previously found mainly relates to limited resolution of light microscopes (the diffraction limit of visible light is 350-500 nm, depending on the wavelength) and the fact that it was not easy to study large surfaces of cells at higher resolution. A whole new world appeared!