Efficient Production of Evolutionary Nanoparticle Newcastle Disease Virus

Abstract

Viruses are routinely isolated from infected cells through freeze–thaw (F–T) cycles or sonication. The aim of this study was to compare different methods for efficient isolation of Newcastle disease virus (NDV) particles from BSR-T7/5 (BSR) cells. The BSR cells were infected with NDV LaSota strain, and the virus particles were isolated via F–T, sonication, sonication followed by F–T, and F–T followed by sonication. The infection and proliferation kinetics of the virus were analyzed by cytopathic observation and monitoring of hemagglutination (HA) titers. The virus isolated by sequential F–T and sonication was amplified through five passages of BSR cells, and then used to infect the HepG2 cells. The viability and apoptosis rates of the infected cells were evaluated by Cell Counting Kit-8 assay and Annexin V-FITC/PI staining respectively. We successfully obtained NDV particles from persistently infected BSR cells through all four methods, which indicated that the LaSota can effectively replicate in BSR cells. However, F–T followed by sonication was optimum in terms of separation effect. The virus particles isolated by this method still exhibited cytolytic activity against HepG2 cells. Thus, our novel method can be applied to NDV production and generation of tumor vaccines.