The C-type lectin DC-SIGN internalizes soluble antigens and HIV-1 virions via a clathrin-dependent mechanism

Eur J Immunol. 2009 Jul;39(7):1923-8. doi: 10.1002/eji.200939351.

Abstract

Dendritic cells (DC), professional Ag-presenting cells located in mucosae and lymphoid organs, operate at the interface of innate and adaptive immunity and are likely the first cells to encounter invading HIV-1. Although the C-type lectin DC-Specific ICAM-3-grabbing non-integrin (DC-SIGN) binds to several viruses, including HIV-1, its direct involvement in viral entry remains controversial. Despite its central role in DC function, little is known about the underlying molecular mechanism(s) of DC-SIGN-mediated Ag uptake. Here, we analyzed the early stages of DC-SIGN-mediated endocytosis and demonstrate that both membrane cholesterol and dynamin are required. Confocal microscopy and clathrin RNAi showed that DC-SIGN-mediated internalization occurs via clathrin-coated pits. Electron microscopy of ultrathin sections showed the involvement of DC-SIGN in clathrin-dependent HIV-1 internalization by DC. Currently, DC-specific C-type lectins are considered potential target in anti-tumor clinical trials. Detailed information about how different Ag are internalized via these receptors will facilitate the rational design of targeted therapeutic strategies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens / metabolism*
  • CHO Cells
  • Cell Adhesion Molecules / genetics
  • Cell Adhesion Molecules / metabolism*
  • Cell Membrane / metabolism
  • Cholesterol / metabolism
  • Clathrin / genetics
  • Clathrin / metabolism*
  • Cricetinae
  • Cricetulus
  • Dendritic Cells / cytology
  • Dendritic Cells / metabolism
  • Dendritic Cells / ultrastructure
  • Dynamins / genetics
  • Dynamins / metabolism
  • Endocytosis
  • HIV-1 / metabolism*
  • Humans
  • Lectins, C-Type / genetics
  • Lectins, C-Type / metabolism*
  • Microscopy, Confocal
  • Microscopy, Electron
  • RNA, Small Interfering / genetics
  • Receptors, Cell Surface / genetics
  • Receptors, Cell Surface / metabolism*
  • Solubility
  • Transfection

Substances

  • Antigens
  • Cell Adhesion Molecules
  • Clathrin
  • DC-specific ICAM-3 grabbing nonintegrin
  • Lectins, C-Type
  • RNA, Small Interfering
  • Receptors, Cell Surface
  • Cholesterol
  • Dynamins