title: DC-SIGN-mediated infectious synapse formation enhances X4 HIV-1 transmission from dendritic cells to T cells.
abstract: Dendritic cells (DCs) are essential for the early events of human immunodeficiency virus (HIV) infection. Model systems of HIV sexual transmission have shown that DCs expressing the DC-specific C-type lectin DC-SIGN capture and internalize HIV at mucosal surfaces and efficiently transfer HIV to CD4+ T cells in lymph nodes, where viral replication occurs. Upon DC-T cell clustering, internalized HIV accumulates on the DC side at the contact zone (infectious synapse), between DCs and T cells, whereas HIV receptors and coreceptors are enriched on the T cell side. Viral concentration at the infectious synapse may explain, at least in part, why DC transmission of HIV to T cells is so efficient.Here, we have investigated the role of DC-SIGN on primary DCs in X4 HIV-1 capture and transmission using small interfering RNA-expressing lentiviral vectors to specifically knockdown DC-SIGN. We demonstrate that DC-SIGN- DCs internalize X4 HIV-1 as well as DC-SIGN+ DCs, although binding of virions is reduced. Strikingly, DC-SIGN knockdown in DCs selectively impairs infectious synapse formation between DCs and resting CD4+ T cells, but does not prevent the formation of DC-T cells conjugates. Our results demonstrate that DC-SIGN is required downstream from viral capture for the formation of the infectious synapse between DCs and T cells. These findings provide a novel explanation for the role of DC-SIGN in the transfer and enhancement of HIV infection from DCs to T cells, a crucial step for HIV transmission and pathogenesis.
authors.affiliation: Dept. of Dermatology and Venereology, University Hospital of Geneva, 4-752, 24 Rue Micheli-du-Crest, 1211 Geneva, Switzerland.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Arrighi
authors.forename: Marjorie
authors.initials: M
authors.lastname: Pion
authors.forename: Eduardo
authors.initials: E
authors.lastname: Garcia
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Escola
authors.forename: Yvette
authors.initials: Y
authors.lastname: van Kooyk
authors.forename: Teunis B
authors.initials: TB
authors.lastname: Geijtenbeek
authors.forename: Vincent
authors.initials: V
authors.lastname: Piguet
mesh_terms: D000911:Antibodies, Monoclonal; D001665:Binding Sites; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000378:metabolism / Q000821:virology*; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D005822:Genetic Vectors; D015658:HIV Infections / Q000378:metabolism / Q000635:transmission*; D015497:HIV-1 / Q000378:metabolism*; D006801:Humans; D037181:Lectins, C-Type / Q000378:metabolism*; D016086:Lentivirus / Q000235:genetics; D008856:Microscopy, Fluorescence; D034741:RNA, Small Interfering / Q000235:genetics; D011956:Receptors, Cell Surface / Q000378:metabolism*; D013601:T-Lymphocytes / Q000378:metabolism / Q000821:virology*; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin
chemical_list: D000911:Antibodies, Monoclonal; D015815:Cell Adhesion Molecules; D037181:Lectins, C-Type; D034741:RNA, Small Interfering; D011956:Receptors, Cell Surface; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin