RSV Growth and Quantification by Microtitration and qRT-PCR Assays.

Defective interfering viral particles have been reported as important determinants of the course of viral infection, and they can markedly temper the virulence of the infection. Here, we describe a simple method, based on limiting dilution, for the removal of defective interfering particles from RSV. This method results in a high-titer viral preparation from both HEp-2 and Vero cell lines. We evaluated two concentrations of sucrose to stabilize the virus preparation, and demonstrate that RSV is stable when prepared and stored in 25 % sucrose at -152 °C. In addition, this chapter describes some commonly used methods of RSV titration, detection using microtitration and quantitative real-time RT-PCR, and the use of immunostaining for antigenic characterization.