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A Simple Flow Cytometry Based Assay to Determine In Vitro Antibody Dependent Enhancement of Dengue Virus Using Zika Virus Convalescent Serum
Published on: April 10, 2018
Lectin-mediated enhancement of dengue virus infection in a mouse macrophage cell line Mk1
Abstract:
Treatment of a mouse macrophage cell line Mk1 with pokeweed mitogen (PWM) either before or during but not after virus inoculation resulted in an enhancement of dengue virus (DV) infection. The infection enhancement was primarily due to an increase in the number of DV-infected cells but not to increased virus production in a cell. These results suggested that PWM treatment mediated increased DV binding and/or penetration to Mk1 cells, thereby resulting in the infection enhancement. N-acetylglucosamine (GlucNAc) did not suppress PWM-mediated enhancement of DV infection when added to Mk1 cells after PWM treatment was done, although GlucNAc clearly suppressed the effect of PWM when added simultaneously with PWM. The results implied the possibility that the PWM-mediated increase in viral binding/penetration was not due to a cross-linking by PWM between DV and a cell-surface receptor, but due to another mechanism, presumably exposure of a masked DV receptor(s). The DV receptor, unidentified as yet, involved in the PWM-mediated infection enhancement appeared to have no relation with IgG Fc receptors that are known to be involved in antibody-mediated enhancement of DV infection.
Insights
Pokeweed mitogen (PWM) enhances dengue virus (DV) infection in macrophages by increasing cell susceptibility, not viral replication. This suggests a novel mechanism involving masked receptor exposure, distinct from Fc receptor pathways.
Area of Science:
- Virology
- Immunology
- Cell Biology
Background:
- Dengue virus (DV) infection is a significant global health concern.
- Mechanisms of viral entry and enhancement are crucial for understanding pathogenesis.
- Macrophage responses to mitogens can modulate viral infections.
Purpose of the Study:
- To investigate the effect of pokeweed mitogen (PWM) on dengue virus infection in a macrophage cell line.
- To elucidate the mechanism underlying PWM-mediated enhancement of DV infection.
- To explore the role of specific cellular receptors in this enhancement.
Main Methods:
- Treatment of mouse macrophage cell line (Mk1) with pokeweed mitogen (PWM) at different time points relative to dengue virus (DV) inoculation.
- Assessment of DV infection levels by quantifying infected cells and virus production.
- Investigation of N-acetylglucosamine (GlucNAc) effects on PWM-mediated enhancement.
Main Results:
- PWM treatment before or during DV inoculation significantly enhanced infection in Mk1 cells.
- Enhancement was attributed to increased numbers of infected cells, not increased virus yield per cell.
- N-acetylglucosamine (GlucNAc) suppressed PWM enhancement only when added simultaneously, suggesting a non-crosslinking mechanism.
Conclusions:
- PWM enhances DV infection by increasing viral binding and/or penetration, likely by exposing a masked DV receptor.
- This mechanism appears distinct from antibody-mediated enhancement involving Fc receptors.
- The study identifies a novel pathway for modulating DV infectivity in macrophages.
