DC-SIGN and DC-SIGNR: helping hands for HIV

The ability of dendritic cells (DCs) to promote HIV infection of T cells efficiently has been linked to the C-type lectin DC-specific intercellular adhesion molecule (ICAM)-grabbing nonintegrin (DC-SIGN). DC-SIGN and its homolog DC-SIGN-related (DC-SIGNR) capture and transmit human and simian immunodeficiency viruses to a wide variety of receptor-positive cells. The expression patterns of DC-SIGN and DC-SIGNR suggest that they might play roles in both horizontal and vertical transmission, as well as dissemination of virus within the host. In vivo experiments are required to prove these hypotheses and might pave the way for the development of new inhibitors of viral entry.