African swine fever (ASF), a contagious and lethal haemorrhagic disease of domestic pigs and wild boars, poses a significant threat to the global pig industry. Although experimental vaccine candidates derived from naturally attenuated, genetically engineered, or cell culture-adapted ASF virus have been tested, no commercial vaccine is accepted globally. We developed a safe and effective cell-adapted live attenuated vaccine candidate (ASFV-MEC-01) by serial passage of a field isolate in CA-CAS-01-A cells. ASFV-MEC-01, isolated via repeated plaque purification using next-generation sequencing analysis, was obtained at passage 18 and showed significant attenuation in 4- and 6-week-old pigs. ASFV-MEC-01 conferred 100% protection against challenge with lethal parental ASFV, which correlated with high ASFV-specific humoral and cellular immune responses. Additionally, ASFV-MEC-01 was not detected in blood until 28 days post-inoculation. Global transcriptome analysis showed that ASFV-MEC-01 lacking 12 genes triggered stronger innate antiviral responses than the parental virus, as exemplified by high levels of mRNA encoding interferon regulatory and inflammatory genes in PAM cells. Ectopic expression of most deleted genes increased replication of DNA viruses by suppressing production of interferons and pro-inflammatory cytokines. Among the genes deleted from ASFV-MEC-01, MGF100-1R interacted specifically with the scaffold dimerization domain of TBK1, thereby preventing TBK1 dimerization and impairing TBK1-mediated type I IFN and NF-κB signalling. These results suggest that attenuation of ASFV-MEC-01 may be mediated by induction of stronger type I IFN and NF-κB signalling within the host innate immune system. Thus, ASFV-MEC-01 could be a safe and effective live attenuated ASFV vaccine candidate with commercial potential.

中文翻译：

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针对非洲猪瘟的高效细胞适应减毒活疫苗候选疫苗的开发和表征。


非洲猪瘟 （ASF） 是一种家猪和野猪的传染性和致命性出血性疾病，对全球养猪业构成重大威胁。尽管已经测试了源自自然减毒、基因工程或细胞培养适应的非洲猪瘟病毒的实验性候选疫苗，但全球尚未接受任何商业疫苗。我们通过在 CA-CAS-01-A 细胞中连续传代现场分离物，开发了一种安全有效的细胞适应减毒活疫苗候选疫苗 （ASFV-MEC-01）。使用下一代测序分析通过重复噬菌斑纯化分离的 ASFV-MEC-01 在第 18 次传代时获得，并在 4 周龄和 6 周龄猪中显示出显著的衰减。ASFV-MEC-01 赋予 100% 的保护，防止致命的亲本 ASFV 的攻击，这与 ASFV 特异性的高体液和细胞免疫反应相关。此外，直到接种后 28 天，血液中才检测到 ASFV-MEC-01。全球转录组分析显示，缺乏 12 个基因的 ASFV-MEC-01 比亲本病毒触发了更强的先天抗病毒反应，PAM 细胞中编码干扰素调节和炎症基因的 mRNA 水平高就是例证。大多数缺失基因的异位表达通过抑制干扰素和促炎细胞因子的产生来增加 DNA 病毒的复制。在从 ASFV-MEC-01 中删除的基因中，MGF100-1R 与 TBK1 的支架二聚化结构域特异性相互作用，从而阻止 TBK1 二聚化并损害 TBK1 介导的 I 型 IFN 和 NF-κB 信号传导。这些结果表明，ASFV-MEC-01 的衰减可能是通过诱导宿主先天免疫系统内更强的 I 型 IFN 和 NF-κB 信号传导来介导的。 因此，ASFV-MEC-01 可能是一种安全有效的 ASFV 减毒活疫苗候选疫苗，具有商业潜力。