title: Primary human splenic macrophages, but not T or B cells, are the principal target cells for dengue virus infection in vitro.
abstract: Understanding the pathogenesis of dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) requires the precise identification of dengue virus (DV)-permissive target cells. In a previous study using unfractionated human peripheral blood mononuclear cells, we found that monocytes, but not B or T cells, were the principal DV-permissive cells in the absence of DV-immune pooled human sera (PHS) and the major mediators of antibody-dependent enhancement in the presence of PHS. To further identify DV-permissive target cells in other tissues and organs, we isolated human splenic mononuclear cells (MNCs), inoculated them with DV type 2 (strain 16681) in the presence or absence of PHS, and assessed their infection either directly using flow cytometry and reverse transcription-PCR (RT-PCR) assays or indirectly by plaque assay. We found that in the absence of PHS, a small proportion of splenic macrophages appeared to be positive for DV antigens in comparison to staining controls by the flow cytometric assay (0.77% +/- 1.00% versus 0.18% +/- 0.12%; P = 0.07) and that viral RNA was detectable by the RT-PCR assay in MNCs exposed to DV. Additionally, supernatants from cultures of DV-exposed MNCs contained infectious virions that were readily detectable by plaque assay. The magnitude of infection was significantly enhanced in splenic macrophages in the presence of highly diluted PHS (5.41% +/- 3.53% versus 0.77% +/- 1.00%; P = 0.001). In contrast, primary T and B cells were not infected in either the presence or absence of PHS. These results provide evidence, for the first time, that human primary splenic macrophages, rather than B or T cells, are the principal DV-permissive cells in the spleen and that they may be uniquely important in the initial steps of immune enhancement that leads to DHF/DSS in some DV-infected individuals.
authors.affiliation: Department of Biology, University of Rochester, Rochester, New York 14642, USA.
authors.forename: Shanley
authors.initials: S
authors.lastname: Blackley
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Kou
authors.forename: Huiyuan
authors.initials: H
authors.lastname: Chen
authors.forename: Matthew
authors.initials: M
authors.lastname: Quinn
authors.forename: Robert C
authors.initials: RC
authors.lastname: Rose
authors.forename: Jacob J
authors.initials: JJ
authors.lastname: Schlesinger
authors.forename: Myra
authors.initials: M
authors.lastname: Coppage
authors.forename: Xia
authors.initials: X
authors.lastname: Jin
mesh_terms: D000818:Animals; D019067:Antibody-Dependent Enhancement; D001402:B-Lymphocytes / Q000276:immunology / Q000821:virology; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003715:Dengue / Q000276:immunology* / Q000503:physiopathology* / Q000821:virology; D003716:Dengue Virus / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D005434:Flow Cytometry; D006801:Humans; D008264:Macrophages / Q000276:immunology* / Q000821:virology; D012367:RNA, Viral / Q000032:analysis / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013154:Spleen / Q000166:cytology* / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology / Q000821:virology; D014709:Vero Cells; D014779:Virus Replication
chemical_list: D012367:RNA, Viral