Targeting DC-SIGN via its neck region leads to prolonged antigen residence in early endosomes, delayed lysosomal degradation, and cross-presentation

Blood. 2011 Oct 13;118(15):4111-9. doi: 10.1182/blood-2011-04-346957. Epub 2011 Aug 22.

Abstract

Targeting antigens to dendritic cell (DC)-specific receptors, such as DC-SIGN, induces potent T cell-mediated immune responses. DC-SIGN is a transmembrane C-type lectin receptor with a long extracellular neck region and a carbohydrate recognition domain (CRD). Thus far, only antibodies binding the CRD have been used to target antigens to DC-SIGN. We evaluated the endocytic pathway triggered by antineck antibodies as well as their intracellular routing and ability to induce CD8(+) T-cell activation. In contrast to anti-CRD antibodies, antineck antibodies induced a clathrin-independent mode of DC-SIGN internalization, as demonstrated by the lack of colocalization with clathrin and the observation that silencing clathrin did not affect antibody internalization in human DCs. Interestingly, we observed that anti-neck and anti-CRD antibodies were differentially routed within DCs. Whereas anti-CRD antibodies were mainly routed to late endosomal compartments, anti-neck antibodies remained associated with early endosomal compartments positive for EEA-1 and MHC class I for up to 2 hours after internalization. Finally, cross-presentation of protein antigen conjugated to antineck antibodies was approximately 1000-fold more effective than nonconjugated antigen. Our studies demonstrate that anti-neck antibodies trigger a distinct mode of DC-SIGN internalization that shows potential for targeted vaccination strategies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies / genetics
  • Antibodies / immunology
  • Antigen Presentation / physiology*
  • Antigens / genetics
  • Antigens / immunology
  • CD8-Positive T-Lymphocytes / immunology*
  • CHO Cells
  • Cell Adhesion Molecules / genetics
  • Cell Adhesion Molecules / immunology*
  • Cricetinae
  • Cricetulus
  • Cross-Priming / physiology*
  • Dendritic Cells / immunology*
  • Endosomes / genetics
  • Endosomes / immunology*
  • Histocompatibility Antigens Class I / genetics
  • Histocompatibility Antigens Class I / immunology
  • Humans
  • Immunity, Cellular / physiology
  • Lectins, C-Type / genetics
  • Lectins, C-Type / immunology*
  • Lysosomes / genetics
  • Lysosomes / immunology*
  • Mice
  • Mice, Transgenic
  • Protein Structure, Tertiary
  • Receptors, Cell Surface / genetics
  • Receptors, Cell Surface / immunology*
  • Vesicular Transport Proteins / genetics
  • Vesicular Transport Proteins / immunology

Substances

  • Antibodies
  • Antigens
  • Cell Adhesion Molecules
  • DC-specific ICAM-3 grabbing nonintegrin
  • Histocompatibility Antigens Class I
  • Lectins, C-Type
  • Receptors, Cell Surface
  • Vesicular Transport Proteins
  • early endosome antigen 1