title: CD4+and CD8+T-cell immunity to Dengue - lessons for the study of Zika virus.
abstract: Dengue virus (DENV) and Zika virus (ZIKV) are rapidly emerging mosquito-borne flaviviruses that represent a public health concern. Understanding host protective immunity to these viruses is critical for the design of optimal vaccines. Over a decade of research has highlighted a significant contribution of the T-cell response to both protection and/or disease enhancement during DENV infection, the latter being mainly associated with sub-optimal cross-reactive T-cell responses during secondary infections. Phase IIb/III clinical trials of the first licensed tetravalent dengue vaccine highlight increased vaccine efficacy in dengue-immune as opposed to dengue-naive vaccinees, suggesting a possible immunoprotective role of pre-existing DENV-specific T cells that are boosted upon vaccination. No vaccine is available for ZIKV and little is known about the T-cell response to this virus. ZIKV and DENV are closely related viruses with a sequence identity ranging from 44% and 56% for the structural proteins capsid and envelope to 68% for the more conserved non-structural proteins NS3/NS5, which represent the main targets of the CD4+and CD8+T-cell response to DENV, respectively. In this review we discuss our current knowledge of T-cell immunity to DENV and what it can teach us for the study of ZIKV. The extent of T-cell cross-reactivity towards ZIKV of pre-existing DENV-specific memory T cells and its potential impact on protective immunity and/or immunopathology will also be discussed.
authors.affiliation: Emerging Infectious Disease Programme, Duke-NUS Medical School, Singapore 169857, Singapore.
authors.forename: Laura
authors.initials: L
authors.lastname: Rivino
authors.affiliation: Emerging Infectious Disease Programme, Duke-NUS Medical School, Singapore 169857, Singapore.
authors.forename: Mei Qiu
authors.initials: MQ
authors.lastname: Lim
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000821:virology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000821:virology; D009033:Culicidae; D003715:Dengue / Q000276:immunology*; D003716:Dengue Virus / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular; D000071244:Zika Virus / Q000276:immunology*; D000071243:Zika Virus Infection / Q000276:immunology*
keywords: T cells; cell trafficking; human; memory; virus