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.

Lineage II of Southeast Asian/American DENV-2 is Associated with a Severe Dengue Outbreak in the Peruvian Amazon

“…54 To assess viral replication kinetics in a cell model that more closely reflects replication in vivo, we also monitored the replication of the two lineages daily over 2 days in primary human mo-DCs, which are considered primary targets for DENV infection in humans. [55][56][57] Because two different donors contributed mo-DCs, we initially tested for an effect of donor on viral replication, but we detected neither an interaction between donor and lineage (rmANOVA, df = 1, 18; P = 0.69) nor an overall effect of donor (rmANOVA, df = 1, 18; P = 0.98) on viral replication kinetics at 48 hours post-infection ( Figure 3A and B). We, therefore, combined data from both donors.…”

Discordance in lymphoid tissue recovery following stem cell transplantation in rhesus macaques: an in vivo imaging study

“…Moreover, the percentage of mononuclear cells that are macrophages is much lower than lymphocytes in spleen and LNs. 16 Hence, the contribution to the total binding sites for the radiotracer, that is, CD4 receptors per unit mass/volume of tissue, brought by the macrophages/ monocytes compartment is expected to be much lower than the contribution brought by the CD4 1 T cells. This is corroborated by the IHC conducted on CD3 1 cells which shows evidence of a substantial pool of T cells that survive the TBI in the spleen but not in the LNs, consistent with the imaging data presented in this study.…”

Evaluating the use of fluorescence-based flow cytometry assay for dengue diagnosis using peripheral blood mononuclear cells

“…This fact has also been reported in previous studies, which have demonstrated that T and B cells are the target cells in dengue infection [23][24][25][26] . Another hypothesis suggests that monocytes are the primary targets in DENV infection and that T and B cells are not infected 27,28 . However, we did not observe this in our study, and in the contrary found that the smallest subpopulation .…”