Abstract
Background
Dengue virus (DENV) is a major global health concern with frequent hepatic involvement that contributes to disease severity. In vitro models using human hepatocyte–derived cell lines are essential for elucidating viral pathogenesis and supporting antiviral research. The HC‐04 cell line, derived from human hepatocytes, has not been extensively characterized as a model for DENV infection.
Methods
HC‐04 cells were infected with DENV‐2 (strain 16681) at a multiplicity of infection (MOI) of 10. Morphological changes were assessed by inverted microscopy. In addition, ultrastructural alterations, cell necrosis, and viral replication were studied by transmission electron microscopy and immunogold electron microscopy for Bax, GRP78, DENV Nonstructural Protein 3 (NS3) and envelope (E) protein, ethidium bromide/acridine orange (EB/AO) staining, and plaque assay, respectively. C6/36 mosquito cells were used as a comparative control for the plaque assay. Additional assessments of morphological changes, viral replication, and necrosis were performed at MOIs of 1 and 5.
Results
Infected HC‐04 cells exhibited cytoplasmic granulation starting from Day 2 postinfection (p.i.), followed by irregular alignment and detachment from Day 4 p.i. Ultrastructural abnormalities on Day 5 p.i. included cytoplasmic vacuolization, lipid droplet accumulation, swollen mitochondria with disrupted cristae, and marked expansion of the rough endoplasmic reticulum. EB/AO staining demonstrated significantly higher necrosis in infected cells than controls. Plaque assays showed viable virus, but the titers were lower than in C6/36 cells (
p
= 0.0162), and intracellular DENV NS3 and E protein were not detected.
Conclusions
DENV‐2 infection induced marked cytopathic and ultrastructural alterations and necrosis in HC‐04 cells. However, it cannot be confirmed whether the cells are permissive to DENV.