DC-SIGNR, a DC-SIGN homologue expressed in endothelial cells, binds to human and simian immunodeficiency viruses and activates infection in trans

DC-SIGN, a C-type lectin expressed on the surface of dendritic cells (DCs), efficiently binds and transmits HIVs and simian immunodeficiency viruses t o susceptible cells in trans, A DC-SIGN homologue, termed DC-SIGNR, has rec ently been described. Herein we show that DC-SIGNR, like DC-SIGN, can bind to multiple strains of HIV-1, HIV-2, and simian immunodeficiency virus and transmit these viruses to both T cell lines and human peripheral blood mono nuclear cells. Binding of virus to DC-SIGNR was dependent on carbohydrate r ecognition. Immunostaining with a DC-SIGNR-specific antiserum showed that D C-SIGNR was expressed on sinusoidal endothelial cells in the liver and on e ndothelial cells in lymph node sinuses and placental villi. The presence of this efficient virus attachment factor on multiple endothelial cell types indicates that DC-SIGNR could play a role in the vertical transmission of p rimate lentiviruses, in the enabling of HIV to traverse the capillary endot helium in some organs, and in the presentation of virus to CD4-positive cel ls in multiple locations including lymph nodes.