Improved Zika virus plaque assay using Vero/TMPRSS2 cell line

Area of Science:

• Virology
• Cell Biology

Background:

• Plaque assays are the gold standard for quantifying viable, cytopathic viruses like Zika virus (ZIKV).
• Standard Vero cells are commonly used for ZIKV titration, but some strains produce plaques that are difficult to visualize and count.
• ZIKV-PRV and ZIKV-CAM strains exhibit poor plaque morphology and visibility on Vero cells.

Purpose of the Study:

• To compare the plaque-forming ability of ZIKV strains on Vero/TMPRSS2 cells versus standard Vero cells.
• To evaluate Vero/TMPRSS2 cells as a potential alternative for improved ZIKV plaque assays.
• To assess the impact of TMPRSS2 expression on ZIKV plaque morphology and visibility.

Main Methods:

• Comparative plaque assays were performed using two ZIKV strains (ZIKV-PRV and ZIKV-CAM).
• Plaque formation and morphology were analyzed on both Vero/TMPRSS2 and standard Vero cell lines.
• Virus stock titers were compared between the two cell types.

Main Results:

• Vero/TMPRSS2 cells produced plaques with significantly improved morphology and visibility for both ZIKV strains compared to Vero cells.
• While Vero cells generated higher quantities of ZIKV stock, Vero/TMPRSS2 cells enhanced plaque assay accuracy for difficult strains.
• ZIKV-PRV plaques were more distinct on Vero/TMPRSS2 cells, and ZIKV-CAM produced observable plaques.

Conclusions:

• Vero/TMPRSS2 cells offer a superior alternative for plaque assays of ZIKV strains that are challenging to titer on standard Vero cells.
• TMPRSS2 expression in Vero cells enhances ZIKV plaque visualization, aiding accurate quantification.
• Standard Vero cells remain more effective for generating high-titer ZIKV stocks.