Sequential production of cytokines by dengue virus-infected human peripheral blood leukocyte cultures

Abstract

The study was undertaken to elucidate the sequence of appearance of T helper (Th)1-and Th2-type cytokines in human peripheral blood leucocyte cultures infected in vitro with dengue type 2 virus. Commercial sandwich enzymelinked immunosorbent assay kits were used to assay the levels of tumour necrosis factor-alpha (TNF-␣), interferon-gamma (IFN-␥), interleukin (IL)-2, IL-4, IL-5, IL-6, and IL-10 in culture supernatants. Culture supernatants were also screened for the cytotoxic factor and the dengue virus titres determined. The cytokines that appeared in the culture supernatants on the first day post-infection (p.i.) were cytotoxic factor, TNF-␣, IL-2, and IL-6; their levels were highest on the second day p.i. IFN-␥ appeared on the second day with a peak on the third day p.i. The levels of these cytokines declined quickly, except for human cytotoxic factor (hCF) and IL-2. The cytokines that appeared later were IL-10 and IL-5 on the fourth day and IL-4 on the sixth day p.i. Dengue virus replicated in the peripheral blood leucocyte (PBL) cultures and was present throughout the course of the study. The findings of the present study show that dengue virus induced a predominant Th1-type cytokine response during the first 3 days of infection of PBL cultures that was replaced by a Th2-type response later.

IL8 release, tight junction and cytoskeleton dynamic reorganization conducive to permeability increase are induced by dengue virus infection of microvascular endothelial monolayers

“…Although studies in vitro cannot be extrapolated to the patient, our data suggest that endothelial alterations could occur in vivo after D2V infection. Mechanisms activated by secreted cytokines could balance the virus-induced alterations and possibly the secretion of anti-inflammatory cytokines by cells of the immune system, to regain tissue homeostasis and eliminate the virus (Chaturvedi et al, 1999). In the case of DHF, severe permeability alterations could be caused by similar mechanisms but inadequate T-cell activation, after a secondary infection, would contribute to the observed pathology, as proposed recently by Mongkolsapaya et al (2003).…”

Dengue Virus Nonstructural Protein NS5 Induces Interleukin-8 Transcription and Secretion

“…The general mechanism of IL-8 induction is through the cytokine network that includes IL-1 and tumor necrosis factor alpha (19). During dengue virus infection, tumor necrosis factor alpha and IL-1␤ are induced in dengue fever and dengue hemorrhagic fever patients and may induce low levels of IL-8 (4,18). Previously, it has been reported that dengue hemorrhagic fever patients tend to have a higher viral burden early in infection (40,68), which may correlate with increased NS5 expression.…”

An External Loop Region of Domain III of Dengue Virus Type 2 Envelope Protein Is Involved in Serotype-Specific Binding to Mosquito but Not Mammalian Cells

“…DV infects a broad range of mammalian cell lines from several species in vitro but is transmitted to humans in vivo by mosquito vectors such as Aedes aegypti and Aedes albopictus (7). Primary human cells such as peripheral blood leukocytes, blood monocytes/macrophages, dendritic cells, and B lymphocytes could also be infected by DV (9,12,13,28,32,33,46,53,55,75,76,82).Previous studies indicate that cell surface heparan sulfates (HS) are involved in attachment of DV to mammalian cells including Vero, CHO, and human hepatoma cells (11,23,31,35,44,54). HS are repeating disaccharides composed of uronic acid or L-iduronic acid and a derivative of glucosamine that is variably O-sulfated (21).…”

“…DV infects a broad range of mammalian cell lines from several species in vitro but is transmitted to humans in vivo by mosquito vectors such as Aedes aegypti and Aedes albopictus (7). Primary human cells such as peripheral blood leukocytes, blood monocytes/macrophages, dendritic cells, and B lymphocytes could also be infected by DV (9,12,13,28,32,33,46,53,55,75,76,82).…”