DC-SIGN

DC-SIGN or CD209 is a C-type lectin receptor present on both macrophages and Dendritic cells.

DC-SIGN on macrophages recognises and binds to mannose type carbohydrates, a class of Pathogen associated molecular patterns PAMPs commonly found on viruses, bacteria and fungi. This binding interaction activates phagocytosis.

On myeloid and pre-plasmacytoid dendritic cells DC-SIGN mediates dendritic cell rolling interactions with blood endothelium and activation of CD4+ T cells, as well as recognition of pathogen haptens.

Role in HIV infection
This molecule is involved in the initial stages of the Human Immunodeficiency Virus infection, as the HIV gp120 molecule causes co-internalization of the DC-SIGN molecule and HIV virion.

The dendritic cell then migrates to the cognate lymphoid organ, whereupon recycling of the DC-SIGN/HIV virion complex to the cell periphery facilitates HIV infection of T cells by interaction between DC-SIGN and ICAM-3.