Den Boon J A，Faaberg K S，Meulenberg J J M，et al． Processing and evolution of the N-terminal region of the arterivirus replicase ORF1a proteins: identification of two?papainlike cysteine proteases[J]． Virol，1995，69:4500－?4505．
Kapur V，Elam M R，Pawlovich T M，et al． Genetic variation in porcine reproductive and respiratory syndrome virus isolates in the midwestern United States[J]． Gen Virol，1996，77(6):1271－1276．
Zhou Y J，Yu H，Tian Z J，et al． Genetic diversity of the?ORF5 gene of porcine reproductive and respiratory syndrome virus isolates in China from 2006 to 2008[J]． Virus Research，2009，144，136－144．
[7]
Ostrowski M，Galeota J A，Jar A M，et al． Identification of?neutralizing and nonneutralizing epitopes in the porcine?reproductive and respiratory syndrome virus GP5 ectodomain[J]． Virol，2002，76，4241－4250．
[8]
Ansari I H，Kwon B J，Osorio F A，et al． Influence of Nlinked glycosylation of porcine reproductive and respiratory syndrome virus GP5 on virus infectivity，antigenicity, and ability to induce neutralizing antibodies[J]． Virol, 2006，80，3994－4004．
[9]
Han J，Liu G P，Wang Y，et al． Identifieation of nonessenrial regions of the Nsp2 replicase protein of PRRSV Strain?VR-2332 for replication in cell culture[J]． Journal of Virology，2007，23:9878－9890．
