Dendritic cells are a type of antigen-presenting cells. They take up infectious substances, such as HIV, and then present them to the immune system's army of T-cells to initiate a strong immune response. For most infections, that's an effective form of action; however, because HIV actually infects T-cells, in this particular case it causes the virus to spread. That's why it's so exciting that the researchers have identified a target molecule called sialic acid-binding Ig-like lectin 1 (Siglec-1, CD169), on the surface of dendritic cells that allows HIV to bond to the cells and be engulfed by then. Blocking that molecule could potentially be an enormous help in preventing infections.
Even more exciting, however, may be the possibility of reducing the role that Siglec-1 plays in trans-infection. Trans-infection is the transfer of HIV virions from dendritic cells to CD4 cells, and it is a key process in the pathogenesis of HIV infection. The researchers showed that blocking Siglec-1 with a monoclonal antibody significantly reduced the ability of dendritic cells to infect their neighboring t-cells with the virus. It will be fascinating to see how this translates to treatment development over the next few years.