Viral Disease Division, Animal and Plant Quarantine Agency, Gimcheon-si 39660, Republic of Korea.
Department of Animal Veterinary Development, BioPOA, Hwaseong-si 18469, Republic of Korea.
Viruses. 2023 Apr 27;15(5):1071. doi: 10.3390/v15051071.
Porcine reproductive and respiratory syndrome virus (PRRSV) is major economic problem given its effects on swine health and productivity. Therefore, we evaluated the genetic stability of a codon pair de-optimized (CPD) PRRSV, E38-ORF7 CPD, as well as the master seed passage threshold that elicited an effective immune response in pigs against heterologous virus challenge. The genetic stability and immune response of every 10th passage (out of 40) of E38-ORF7 CPD was analyzed through whole genome sequencing and inoculation in 3-week-old pigs. E38-ORF7 CPD passages were limited to 20 based on the full-length mutation analysis and animal test results. After 20 passages, the virus could not induce antibodies to provide effective immunity and mutations accumulated in the gene, which differed from the CPD gene, presenting a reason for low infectivity. Conclusively, the optimal passage number of E38-ORF7 CPD is 20. As a vaccine, this may help overcome the highly diverse PRRSV infection with substantially enhanced genetic stability.
猪繁殖与呼吸综合征病毒（PRRSV）对猪的健康和生产力有影响，是一个主要的经济问题。因此，我们评估了一种密码子对去优化（CPD）的 PRRSV，E38-ORF7 CPD 的遗传稳定性，以及引发猪对异源病毒攻击产生有效免疫反应的主种子传代阈值。通过对 3 周龄猪进行全基因组测序和接种，分析了 E38-ORF7 CPD 的每 10 次传代（共 40 次）的遗传稳定性和免疫反应。基于全长突变分析和动物试验结果，E38-ORF7 CPD 的传代次数被限制在 20 次以内。20 次传代后，病毒不能诱导产生抗体提供有效免疫，基因中积累了突变，与 CPD 基因不同，这是感染性降低的原因。总之，E38-ORF7 CPD 的最佳传代次数是 20 次。作为一种疫苗，这可能有助于克服高度多样化的 PRRSV 感染，同时显著提高遗传稳定性。
