title: Source and Purity of Dengue-Viral Preparations Impact Requirement for Enhancing Antibody to Induce Elevated IL-1β Secretion: A Primary Human Monocyte Model.
abstract: Dengue virus is a major global health threat and can lead to life-threatening hemorrhagic complications due to immune activation and cytokine production. Cross-reactive antibodies to an earlier dengue virus infection are a recognized risk factor for severe disease. These antibodies bind heterologous dengue serotypes and enhance infection into Fc-receptor-bearing cells, a process known as antibody-dependent enhancement of infection. One crucial cytokine seen elevated in severe dengue patients is IL-1β, a potent inflammatory cytokine matured by the inflammasome. We used a highly-physiologic system by studying antibody-dependent enhancement of IL-1β in primary human monocytes with anti-dengue human monoclonal antibodies isolated from patients. Antibody-enhancement increased viral replication in primary human monocytes inoculated with supernatant harvested from Vero cells infected with dengue virus serotype 2 (DENV-2) 16681. Surprisingly, IL-1β secretion induced by infectious supernatant harvested from two independent Vero cell lines was not enhanced by antibody. Secretion of multiple other inflammatory cytokines was also independent of antibody signaling. However, IL-1β secretion did require NLRP3 and caspase-1 activity. Immunodepletion of dengue virions from the infectious supernatant confirmed that virus was not the main IL-1β-inducing agent, suggesting that a supernatant component(s) not associated with the virion induced IL-1β production. We excluded RNA, DNA, contaminating LPS, viral NS1 protein, complement, and cytokines. In contrast, purified Vero-derived DENV-2 16681 exhibited antibody-enhancement of both infection and IL-1β induction. Furthermore, C6/36 mosquito cells did not produce such an inflammatory component, as crude supernatant harvested from insect cells infected with DENV-2 16681 induced antibody-dependent IL-1β secretion. This study indicates that Vero cells infected with DENV-2 16681 may produce inflammatory components during dengue virus propagation that mask the virus-specific immune response. Thus, the choice of host cell and viral purity should be carefully considered, while insect-derived virus represents a system that elicits antibody-dependent cytokine responses to dengue virus with fewer confounding issues.
authors: Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America; The Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America.
authors: Justin B
authors: JB
authors: Callaway
authors: The Vanderbilt Vaccine Center, Vanderbilt Medical Center, Nashville, TN, United States of America; Department of Medicine, Vanderbilt Medical Center, Nashville, TN, United States of America.
authors: Scott A
authors: SA
authors: Smith
authors: Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America.
authors: Douglas G
authors: DG
authors: Widman
authors: Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America; The Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America.
authors: Karen P
authors: KP
authors: McKinnon
authors: Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States of America.
authors: Frank
authors: F
authors: Scholle
authors: Duke Human Vaccine Institute, Durham, NC, United States of America.
authors: Gregory D
authors: GD
authors: Sempowski
authors: Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America; The Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America.
authors: Dirk P
authors: DP
authors: Dittmer
authors: The Vanderbilt Vaccine Center, Vanderbilt Medical Center, Nashville, TN, United States of America; Department of Pathology, Microbiology and Immunology, Vanderbilt Medical Center, Nashville, TN, United States of America; Department of Pediatrics, Vanderbilt Medical Center, Nashville, TN, United States of America.
authors: James E
authors: JE
authors: Crowe
authors: Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America.
authors: Aravinda M
authors: AM
authors: de Silva
authors: Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America; The Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America; Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America.
authors: Jenny P-Y
authors: JP
authors: Ting
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000008:administration & dosage; D000914:Antibodies, Viral / Q000008:administration & dosage / Q000276:immunology*; D002522:Chlorocebus aethiops; D003716:Dengue Virus / Q000276:immunology* / Q000472:pathogenicity; D006801:Humans; D053583:Interleukin-1beta / Q000276:immunology / Q000378:metabolism*; D009000:Monocytes / Q000276:immunology / Q000821:virology; D019595:Severe Dengue / Q000276:immunology* / Q000821:virology; D014709:Vero Cells; D014779:Virus Replication / Q000276:immunology
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D053583:Interleukin-1beta