TY - JOUR
T1 - Development of a broadly protective modified-live virus vaccine candidate against porcine reproductive and respiratory syndrome virus
AU - Sun, Haiyan
AU - Workman, Aspen
AU - Osorio, Fernando A.
AU - Steffen, David
AU - Vu, Hiep L.X.
N1 - Funding Information:
We thank Hong-Yen Pham and Kenneth McFarland for their laboratory assistance. This research was supported by the U.S. National Pork Board Grant no. 15-159 (HLXV), and by Agriculture and Food Research Initiative Competitive Grant no. 2016-67015-24922 (HLXV) and Grant no. 2013-01035 (FAO) from the USDA National Institute of Food and Agriculture.
Publisher Copyright:
© 2017 Elsevier Ltd
PY - 2018/1/2
Y1 - 2018/1/2
N2 - Modified-live virus (MLV) vaccines are widely used to protect pigs against porcine reproductive and respiratory syndrome virus (PRRSV). However, current MLV vaccines do not confer adequate levels of heterologous protection, presumably due to the substantial genetic diversity of PRRSV isolates circulating in the field. To overcome this genetic variation challenge, we recently generated a synthetic PRRSV strain containing a consensus genomic sequence of PRRSV-2. We demonstrated that our synthetic PRRSV strain confers unprecedented levels of heterologous protection. However, the synthetic PRRSV strain at passage 1 (hereafter designated CON-P1) is highly virulent and therefore, is not suitable to be used as a vaccine in pigs. In the present study, we attenuated CON-P1 by continuously passaging the virus in MARC-145 cells, a non-natural host cell line. Using a young pig model, we demonstrated that the synthetic virus at passages 90 and 122 (designated as CON-P90 and CON-P122, respectively) were fully attenuated, as evidenced by the significantly reduced viral loads in serum and tissues and the absence of lung lesion in the infected pigs. Most importantly, CON-P90 confers similar levels of heterologous protection as its parental strain CON-P1. Taken together, the results indicate that CON-P90 is an excellent candidate for the formulation of next generation of PRRSV MLV vaccines with improved levels of heterologous protection.
AB - Modified-live virus (MLV) vaccines are widely used to protect pigs against porcine reproductive and respiratory syndrome virus (PRRSV). However, current MLV vaccines do not confer adequate levels of heterologous protection, presumably due to the substantial genetic diversity of PRRSV isolates circulating in the field. To overcome this genetic variation challenge, we recently generated a synthetic PRRSV strain containing a consensus genomic sequence of PRRSV-2. We demonstrated that our synthetic PRRSV strain confers unprecedented levels of heterologous protection. However, the synthetic PRRSV strain at passage 1 (hereafter designated CON-P1) is highly virulent and therefore, is not suitable to be used as a vaccine in pigs. In the present study, we attenuated CON-P1 by continuously passaging the virus in MARC-145 cells, a non-natural host cell line. Using a young pig model, we demonstrated that the synthetic virus at passages 90 and 122 (designated as CON-P90 and CON-P122, respectively) were fully attenuated, as evidenced by the significantly reduced viral loads in serum and tissues and the absence of lung lesion in the infected pigs. Most importantly, CON-P90 confers similar levels of heterologous protection as its parental strain CON-P1. Taken together, the results indicate that CON-P90 is an excellent candidate for the formulation of next generation of PRRSV MLV vaccines with improved levels of heterologous protection.
KW - Heterologous protection
KW - MLV
KW - PRRSV
KW - Synthetic virus
UR - http://www.scopus.com/inward/record.url?scp=85035066209&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85035066209&partnerID=8YFLogxK
U2 - 10.1016/j.vaccine.2017.11.028
DO - 10.1016/j.vaccine.2017.11.028
M3 - Article
C2 - 29174314
AN - SCOPUS:85035066209
SN - 0264-410X
VL - 36
SP - 66
EP - 73
JO - Vaccine
JF - Vaccine
IS - 1
ER -