title: Human herpesvirus 8 infects and replicates in primary cultures of activated B lymphocytes through DC-SIGN.
abstract: Human herpesvirus 8 (HHV-8) is the etiological agent of Kaposi's sarcoma, primary effusion lymphoma, and some forms of multicentric Castleman's disease. Although latent HHV-8 DNA can be detected in B cells from persons with these cancers, there is little information on the replication of HHV-8 in B cells. Indeed, B cells are relatively resistant to HHV-8 infection in vitro. We have recently shown that DC-SIGN, a C-type lectin first identified on dendritic cells (DC), is an entry receptor for HHV-8 on DC and macrophages. We have also demonstrated previously that B lymphocytes from peripheral blood and tonsils express DC-SIGN and that this expression increases after B-cell activation. Here we show that activated blood and tonsillar B cells can be productively infected with HHV-8, as measured by an increase in viral DNA, the expression of viral lytic and latency proteins, and the production of infectious virus. The infection of B cells with HHV-8 was blocked by the pretreatment of the cells with antibody specific for DC-SIGN or with mannan but not antibody specific for xCT, a cystine/glutamate exchange transporter that has been implicated in HHV-8 fusion to cells. The infection of B cells with HHV-8 resulted in increased expression of DC-SIGN and a decrease in the expression of CD20 and major histocompatibility complex class I. HHV-8 could also infect and replicate in B-cell lines transduced to express full-length DC-SIGN but not in B-cell lines transduced to express DC-SIGN lacking the transmembrane domain, demonstrating that the entry of HHV-8 into B cells is related to DC-SIGN-mediated endocytosis. The role of endocytosis in viral entry into activated B cells was confirmed by blocking HHV-8 infection with endocytic pathway inhibitors. Thus, the expression of DC-SIGN is essential for productive HHV-8 infection of and replication in B cells.
authors.affiliation: Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, 604 Parran Hall, 130 De Soto St., Pittsburgh, PA 15261, USA. giovanna@pitt.edu
authors.forename: Giovanna
authors.initials: G
authors.lastname: Rappocciolo
authors.forename: Heather R
authors.initials: HR
authors.lastname: Hensler
authors.forename: Mariel
authors.initials: M
authors.lastname: Jais
authors.forename: Todd A
authors.initials: TA
authors.lastname: Reinhart
authors.forename: Amarendra
authors.initials: A
authors.lastname: Pegu
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Jenkins
authors.forename: Charles R
authors.initials: CR
authors.lastname: Rinaldo
mesh_terms: D000911:Antibodies, Monoclonal / Q000378:metabolism; D018951:Antigens, CD20 / Q000096:biosynthesis; D001402:B-Lymphocytes / Q000737:chemistry / Q000821:virology*; D015815:Cell Adhesion Molecules / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D002478:Cells, Cultured; D004279:DNA, Viral / Q000096:biosynthesis; D004705:Endocytosis; D019288:Herpesvirus 8, Human / Q000254:growth & development*; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis; D006801:Humans; D037181:Lectins, C-Type / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D011991:Receptors, Virus / Q000502:physiology*; D014764:Viral Proteins / Q000096:biosynthesis; D053586:Virus Internalization; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin
chemical_list: D000911:Antibodies, Monoclonal; D018951:Antigens, CD20; D015815:Cell Adhesion Molecules; D004279:DNA, Viral; D015395:Histocompatibility Antigens Class I; D037181:Lectins, C-Type; D011956:Receptors, Cell Surface; D011991:Receptors, Virus; D014764:Viral Proteins; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin