To develop a modified live vaccine (MLV) against porcine reproductive and respiratory syndrome virus (PRRSV), virulent CH-Ia strain was attenuated by serial passages up to 130 passage (P130) in Marc-145 cells. T...To develop a modified live vaccine (MLV) against porcine reproductive and respiratory syndrome virus (PRRSV), virulent CH-Ia strain was attenuated by serial passages up to 130 passage (P130) in Marc-145 cells. The virulence and immune efficacy of the attenuated CH-1 a were evaluated in pigs. The results showed that animals inoculated with P130 did not develop any clinical sign of the disease, but produced rapid and effective humoral immune responses against PRRSV challenge, indicating that attenuated CH-1 a P 130 is the candidate as the effective vaccine against PRRSV. To define the potential mutations in the attenuated CH-la genome, we sequenced and analyzed the ORF5 gene of CH-la strain of different passages (P39, P55, P65, P70, P85, P100, P115, P120, P125, and P130) and found that three mutations (C5Y, H38Q and L146Q) which may be related with the attenuation of CH-la. In addition, we also found a unique restriction enzyme site (TspEI) in the ORF5 gene of attenuated CH-la, which can be used as a genetic marker to distinguish original and attenuated CH- 1 a.展开更多
基金supported by the National High Technology Research and Development Program of China(2011AA10A213)the Key Technology R&D Program of Harbin, China(2010AA6AN083)the Excellent Youth Foundation of Heilongjiang Province of China(JC201020)
文摘To develop a modified live vaccine (MLV) against porcine reproductive and respiratory syndrome virus (PRRSV), virulent CH-Ia strain was attenuated by serial passages up to 130 passage (P130) in Marc-145 cells. The virulence and immune efficacy of the attenuated CH-1 a were evaluated in pigs. The results showed that animals inoculated with P130 did not develop any clinical sign of the disease, but produced rapid and effective humoral immune responses against PRRSV challenge, indicating that attenuated CH-1 a P 130 is the candidate as the effective vaccine against PRRSV. To define the potential mutations in the attenuated CH-la genome, we sequenced and analyzed the ORF5 gene of CH-la strain of different passages (P39, P55, P65, P70, P85, P100, P115, P120, P125, and P130) and found that three mutations (C5Y, H38Q and L146Q) which may be related with the attenuation of CH-la. In addition, we also found a unique restriction enzyme site (TspEI) in the ORF5 gene of attenuated CH-la, which can be used as a genetic marker to distinguish original and attenuated CH- 1 a.