Quantitative expression and virus transmission analysis of DC-SIGN on monocyte-derived dendritic cells.
The C-type lectins DC-SIGN and DC-SIGNR efficiently bind human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) strains and can transmit bound virus to adjacent CD4-positive cells. DC-SIGN also binds efficiently to the Ebola virus glycoprotein, enhancing Ebola virus infection. DC-SIGN is thought to be responsible for the ability of dendritic cells (DCs) to capture HIV and transmit it to T cells, thus promoting HIV dissemination in vitro and perhaps in vivo as well. To investigate DC-SIGN function and expression levels on DCs, we characterized a panel of monoclonal antibodies (MAbs) directed against the carbohydrate recognition domain of DC-SIGN. Using quantitative fluorescence-activated cell sorter technology, we found that DC-SIGN is highly expressed on immature monocyte-derived DCs, with at least 100,000 copies and often in excess of 250,000 copies per DC. There was modest variation (three- to fourfold) in DC-SIGN expression levels between individuals and between DCs isolated from the same individual at different times. Several MAbs efficiently blocked virus binding to cell lines expressing human or rhesus DC-SIGN, preventing HIV and SIV transmission. Interactions with Ebola virus pseudotypes were also blocked efficiently. Despite their ability to block virus-DC-SIGN interactions on cell lines, these antibodies only inhibited transmission of virus from DCs by approximately 50% or less. These results indicate that factors other than DC-SIGN may play important roles in the ability of DCs to capture and transmit HIV.
Department of Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Frédéric
F
Baribaud
Stefan
S
Pöhlmann
George
G
Leslie
Frank
F
Mortari
Robert W
RW
Doms
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000378:metabolism; D015815:Cell Adhesion Molecules; D002460:Cell Line; D003713:Dendritic Cells / Q000378:metabolism* / Q000821:virology; D005434:Flow Cytometry; D015658:HIV Infections / Q000635:transmission* / Q000821:virology; D015497:HIV-1 / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D037102:Lectins / Q000378:metabolism*; D037181:Lectins, C-Type; D008253:Macaca mulatta; D009000:Monocytes; D011956:Receptors, Cell Surface / Q000378:metabolism*; D016097:Simian Acquired Immunodeficiency Syndrome / Q000635:transmission* / Q000821:virology; D015302:Simian Immunodeficiency Virus / Q000378:metabolism* / Q000502:physiology; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin
D000911:Antibodies, Monoclonal; D015815:Cell Adhesion Molecules; D037102:Lectins; D037181:Lectins, C-Type; D011956:Receptors, Cell Surface; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin; C433029:CLEC4M protein, human