title: Targeting DC-SIGN via its neck region leads to prolonged antigen residence in early endosomes, delayed lysosomal degradation, and cross-presentation.
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.
authors.affiliation: Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Tacken
authors.forename: Wiebke
authors.initials: W
authors.lastname: Ginter
authors.forename: Luciana
authors.initials: L
authors.lastname: Berod
authors.forename: Luis J
authors.initials: LJ
authors.lastname: Cruz
authors.forename: Ben
authors.initials: B
authors.lastname: Joosten
authors.forename: Tim
authors.initials: T
authors.lastname: Sparwasser
authors.forename: Carl G
authors.initials: CG
authors.lastname: Figdor
authors.forename: Alessandra
authors.initials: A
authors.lastname: Cambi
mesh_terms: D000818:Animals; D000906:Antibodies / Q000235:genetics / Q000276:immunology; D017951:Antigen Presentation / Q000502:physiology*; D000941:Antigens / Q000235:genetics / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D016466:CHO Cells; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000276:immunology*; D006224:Cricetinae; D003412:Cricetulus; D045142:Cross-Priming / Q000502:physiology*; D003713:Dendritic Cells / Q000276:immunology*; D011992:Endosomes / Q000235:genetics / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000276:immunology; D006801:Humans; D007111:Immunity, Cellular / Q000502:physiology; D037181:Lectins, C-Type / Q000235:genetics / Q000276:immunology*; D008247:Lysosomes / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008822:Mice, Transgenic; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface / Q000235:genetics / Q000276:immunology*; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000276:immunology; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin
chemical_list: D000906:Antibodies; D000941:Antigens; D015815:Cell Adhesion Molecules; D015395:Histocompatibility Antigens Class I; D037181:Lectins, C-Type; D011956:Receptors, Cell Surface; D033921:Vesicular Transport Proteins; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin; C093846:early endosome antigen 1