Plaque formation by human-origin parainfluenza type 2 virus in established cell lines

Area of Science:

• Virology
• Cell Biology

Background:

• Parainfluenza virus type 2 (PIV2) is a significant respiratory pathogen.
• Efficient methods for quantifying PIV2 infectivity are crucial for research and diagnostics.

Purpose of the Study:

• To evaluate the plaque-forming ability of different PIV2 strains in various cell lines.
• To determine the necessity of trypsin for plaque formation by PIV2.

Main Methods:

• Plaque assays were performed using two PIV2 strains (Toshiba and 62-M786).
• Experiments were conducted in Vero cells, with and without trypsin supplementation.
• Toshiba strain was also tested in HeLa, BHK, LLC-MK2, and mouse L cell lines.

Main Results:

• Both PIV2 strains formed well-defined plaques in Vero cells.
• The Toshiba strain formed plaques in Vero cells without trypsin.
• The 62-M786 strain required trypsin for plaque formation in Vero cells.
• The Toshiba strain formed plaques in HeLa, BHK, and LLC-MK2 cells but not in mouse L cells.
• Plaque assay sensitivity was comparable to the hemadsorption method.

Conclusions:

• Different PIV2 strains exhibit distinct cell culture tropisms and requirements for plaque formation.
• Trypsin supplementation is critical for plaque assay of certain PIV2 strains.
• Plaque assays provide a sensitive method for PIV2 quantification.