Internalization and propagation of the dengue virus in human hepatoma (HepG2) cells

Abstract

Objectives: This study sought to undertake a comparative analysis of the internalization and propagation of all four dengue serotypes in a single cell line of human liver origin, HepG2. Methods: Virus production after infection was determined by the plaque assay technique. Internalization profiles were determined by incubating virus and cells on ice and then raising the temperature for various times. The contribution of extracellular matrix components to internalization was determined by pretreatment of cells with either trypsin or heparinase III. Results: HepG2 cells were able to support the propagation of all four serotypes with mature viruses being produced by 12 h for dengue serotype 4 and by 17-18 h for the remaining serotypes. Virus internalization showed a plateau for serotypes 1, 2 and 4 entry while serotype 3 showed a constant increase in internalization for up to 5 h. Pretreatment of HepG2 cells with heparinase III or trypsin both resulted in a reduction in viral production, with the smallest effect being noted for dengue serotype 3. Conclusion: These results suggest that the interaction between the dengue virus and liver cells is a complex one that requires both protein and nonprotein elements, and has a significant serotype/strain element. Copyright © 2004 S. Karger AG, Basel.