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American genotype structures decrease dengue virus output from human monocytes and dendritic cells
Raymond Cologna1, Rebeca Rico-Hesse
1Department of Virology and Immunology, Southwest Foundation for Biomedical Research, San Antonio, Texas 78227, USA.
Journal of Virology
|March 14, 2003
Summary
Genetic mutations in dengue virus type 2, specifically in the envelope glycoprotein (E) gene and terminal regions, significantly reduce viral replication in human cells. These findings offer insights into dengue virus virulence and potential therapeutic targets.
Area of Science:
- Virology
- Molecular Biology
- Immunology
Background:
- Dengue virus type 2 virulence factors were previously identified through genomic sequencing of American and Southeast Asian genotypes.
- Understanding genetic determinants of dengue virus pathogenesis is crucial for controlling disease spread.
Purpose of the Study:
- To investigate the impact of mutations in the dengue virus type 2 envelope glycoprotein (E) gene and non-translated regions on viral replication in human cells.
- To assess the synergistic effects of these genetic modifications on dengue virus output and virulence.
Main Methods:
- Generation of chimeric infectious dengue virus clones with varying combinations of American and SE Asian genotype sequences.
- Evaluation of viral replication rates in human primary cell cultures (macrophages, dendritic cells) and mosquito cells using plaque assays and quantitative reverse transcription-PCR.
- Measurement of viral RNA output per infected cell to quantify replication efficiency.
Main Results:
- Chimeric viruses exhibited altered plaque morphology in mammalian cells but similar replication rates in mosquito cells.
- Consistent differences in viral RNA output per infected human cell were observed, varying by donor.
- A chimeric virus with an E gene mutation showed reduced virus output, with a more significant reduction in a triple mutant and the American genotype wild-type virus.
- The studied mutations appear to function synergistically, with the E mutation alone causing a lower output than 5'- and 3'-terminal mutations.
Conclusions:
- Specific genetic changes, including E gene mutations and alterations in 5'- and 3'-terminal non-translated regions, can decrease dengue virus replication in human target cells.
- These modifications may contribute to reduced dengue virus virulence during human infection.
- The findings suggest potential targets for therapeutic interventions aimed at controlling dengue virus pathogenesis.