Li Chao, Li Jinhao, Gong Bangjun, Xu Hu, Guo Zhenyang, Xiang Lirun, Zhang Siyu, Sun Qi, Zhao Jing, Zhang Menglin, Tang Yan-Dong, Leng Chaoliang, Wu Jianan, Wang Qian, Peng Jinmei, Zhou Guohui, Liu Huairan, An Tongqing, Cai Xuehui, Tian Zhi-Jun, Zhang Hongliang
State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
Henan Provincial Engineering and Technology Center of Animal Disease Diagnosis and Integrated Control, Nanyang Normal University, Nanyang, China.
Virulence. 2025 Dec;16(1):2451754. doi: 10.1080/21505594.2025.2451754. Epub 2025 Jan 12.
Multiple porcine reproductive and respiratory syndrome virus (PRRSV) subtypes coinfect numerous pig farms in China, and commercial PRRSV vaccines offer limited cross-protection against heterologous strains. Our previous research confirmed that a PRRSV lineage 1 branch attenuated live vaccine (SD-R) provides cross-protection against HP-PRRSV, NADC30-like PRRSV and NADC34-like PRRSV. HP-PRRSV has undergone significant genetic variation following nearly two decades of evolution and has transformed into a subtype referred to as HP-like PRRSV, which also exhibits high pathogenicity. The effectiveness of immunising piglets with the SD-R strain to provide protection against infection with HP-like PRRSV remains uncertain. In the present study, we evaluated the protective effects of SD-R vaccine strains on DLF-challenged piglets. The results revealed that piglets challenged with DLF presented clinical symptoms such as continuous high fever and an obvious decrease in daily weight gain. Importantly, the piglets immunised with SD-R exhibited notable reductions in pathological damage, especially of decreases in DLF-induced thymic atrophy. Moreover, the serum of SD-R-immunised piglets strongly neutralised DLF, and the number of SD-R-vaccinated piglets demonstrating viraemia was greatly reduced. These results suggest that the PRRSV lineage 1 branch live vaccine candidate provides broad cross-protection against HP-like PRRSV in piglets.
多种猪繁殖与呼吸综合征病毒（PRRSV）亚型在中国众多猪场共同感染，而市售PRRSV疫苗对异源毒株的交叉保护作用有限。我们之前的研究证实，一种PRRSV 1型分支减毒活疫苗（SD-R）对高致病性PRRSV（HP-PRRSV）、NADC30样PRRSV和NADC34样PRRSV具有交叉保护作用。经过近二十年的进化，HP-PRRSV发生了显著的基因变异，并转变为一种称为类HP-PRRSV的亚型，该亚型也具有高致病性。用SD-R毒株免疫仔猪以预防类HP-PRRSV感染的有效性仍不确定。在本研究中，我们评估了SD-R疫苗毒株对经DLF攻击的仔猪的保护作用。结果显示，经DLF攻击的仔猪出现持续高烧和日增重明显下降等临床症状。重要的是，用SD-R免疫的仔猪病理损伤显著减轻，尤其是DLF诱导的胸腺萎缩减轻。此外，用SD-R免疫的仔猪血清对DLF具有强烈的中和作用，并且出现病毒血症的SD-R疫苗接种仔猪数量大幅减少。这些结果表明，PRRSV 1型分支候选活疫苗对仔猪的类HP-PRRSV提供广泛的交叉保护。
