Porcine reproductive and respiratory syndrome (PRRS) is a globally prevalent contagious disease caused by the positive-strand RNA PRRS virus (PRRSV), resulting in substantial economic losses in the swine industry. Modifying the CD163 SRCR5 domain, either through deletion or substitution, can eff1ectively confer resistance to PRRSV infection in pigs. However, large fragment modifications in pigs inevitably raise concerns about potential adverse effects on growth performance. Reducing the impact of genetic modifications on normal physiological functions is a promising direction for developing PRRSV-resistant pigs. In the current study, we identified a specific functional amino acid in CD163 that influences PRRSV proliferation. Viral infection experiments conducted on Marc145 and PK-15 CD163 cells illustrated that the mE535G or corresponding pE529G mutations markedly inhibited highly pathogenic PRRSV (HP-PRRSV) proliferation by preventing viral binding and entry. Furthermore, individual viral challenge tests revealed that pigs with the E529G mutation had viral loads two orders of magnitude lower than wild-type (WT) pigs, confirming effective resistance to HP-PRRSV. Examination of the physiological indicators and scavenger function of CD163 verified no significant differences between the WT and E529G pigs. These findings suggest that E529G pigs can be used for breeding PRRSV-resistant pigs, providing novel insights into controlling future PRRSV outbreaks.
猪繁殖与呼吸综合征（PRRS）是一种由正链RNA病毒PRRSV引起的世界性传染病，给养猪业造成了巨大的经济损失。敲除或替换 CD163 SRCR5结构域可有效抵抗猪PRRSV感染。然而，大片段修饰猪的生长性能不可避免受到担忧。减少基因修饰对正常生理功能的影响是PRRS抗病育种的一个有前景的方向。在该研究中，我们鉴定了CD163中一个影响PRRSV增殖的功能性氨基酸。体外病毒感染实验表明，E535G突变的Marc145细胞通过抑制PRRSV结合和侵入细胞而显著抑制HP-PRRSV的增殖，在稳定表达CD163的PK-15细胞中相应位点E529G突变后也观察到了同样的结果。此外，个体攻毒实验显示E529G猪的病毒载量比野生型猪的低两个数量级，H＆E染色和免疫组化等结果均证实E529G猪能有效抵抗HP-PRRSV。对猪的生理指标和CD163的清除功能的检测证实WT和E529G猪之间没有明显差异。综上所述，E529G猪可以用于培育抗PRRS猪，功能氨基酸位点突变策略为防控未来PRRSV暴发提供了新的见解。.
Keywords: CD163; E529G; PRRSV; Pigs; Point mutation.