Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) is a member of the family Arteriviridae, order Nidovirale. PRRSV is an enveloped, single-stranded, positive-sense RNA virus with a genome around 15 kb in length. For propagation of PRRSV in vitro, the MARC-145 cell line is the most often used in a laboratory setting. Infectious cDNA clones of many PRRSV strains have been established, from which these viruses can be recovered. PRRSV titration is generally done in MARC-145 cells. PRRSV RNA copy numbers can be assessed by reverse transcription and real-time PCR. Here, protocols for PRRSV propagation, virus recovery from infectious cDNA clones, and quantification are presented. © 2018 by John Wiley & Sons, Inc.