Abstract
Dendritic cells (DCs) are essential antigen-presenting cells for the induction of immunity against pathogens. However, HIV-1 spread is strongly enhanced in clusters of DCs and CD4(+) T cells. Uninfected DCs capture HIV-1 and mediate viral transfer to bystander CD4(+) T cells through a process termed trans-infection. Initial studies identified the C-type lectin DC-SIGN as the HIV-1 binding factor on DCs, which interacts with the viral envelope glycoproteins. Upon DC maturation, however, DC-SIGN is down-regulated, while HIV-1 capture and trans-infection is strongly enhanced via a glycoprotein-independent capture pathway that recognizes sialyllactose-containing membrane gangliosides. Here we show that the sialic acid-binding Ig-like lectin 1 (Siglec-1, CD169), which is highly expressed on mature DCs, specifically binds HIV-1 and vesicles carrying sialyllactose. Furthermore, Siglec-1 is essential for trans-infection by mature DCs. These findings identify Siglec-1 as a key factor for HIV-1 spread via infectious DC/T-cell synapses, highlighting a novel mechanism that mediates HIV-1 dissemination in activated tissues.
Publication types
-
Research Support, Non-U.S. Gov't
-
Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
-
Dendritic Cells / drug effects
-
Dendritic Cells / metabolism*
-
Dendritic Cells / virology*
-
Exosomes / drug effects
-
Exosomes / metabolism
-
Gangliosides / metabolism*
-
Gene Silencing / drug effects
-
HEK293 Cells
-
HIV Infections / immunology*
-
HIV Infections / pathology
-
HIV Infections / virology
-
HIV-1 / physiology*
-
Humans
-
Immunological Synapses / drug effects
-
Lipid Bilayers / metabolism*
-
Lipopolysaccharides / pharmacology
-
Liposomes / metabolism
-
Sialic Acid Binding Ig-like Lectin 1 / metabolism*
-
Up-Regulation / drug effects
-
Virion / drug effects
-
Virion / metabolism
Substances
-
Gangliosides
-
Lipid Bilayers
-
Lipopolysaccharides
-
Liposomes
-
Sialic Acid Binding Ig-like Lectin 1
Grants and funding
This work was supported by the Spanish Ministry of Science and Innovation through grant SAF2010-21224, the Spanish AIDS network “Red Temática Cooperativa de Investigación en SIDA” (RD06/0006), the Catalan HIV Vaccine Development Program (HIVACAT), Gala contra la sida: Barcelona 2011, and by a grant from the Deutsche Forschungsgemeinschaft to H.-G.K. (TRR83; project 14). N.I-U. was supported by the program “José Castillejo” from the Spanish Ministry of Education. M.T.R.-P. is supported by grant BES-2008-002609 from the Spanish Ministry of Science and Innovation H.-G.K. is investigator of the Cell Networks Cluster of Excellence (EXC81). A.T. is supported by the Swiss National Science Foundation (31003A_132863). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.