Borca Manuel V, Ramirez-Medina Elizabeth, Silva Ediane, Rai Ayushi, Espinoza Nallely, Velazquez-Salinas Lauro, Gladue Douglas P
Plum Island Animal Disease Center, ARS, USDA, Greenport, NY 11944, USA.
Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN 37830, USA.
Pathogens. 2023 Jun 6;12(6):805. doi: 10.3390/pathogens12060805.
African swine fever (ASF) is an important disease in swine currently producing a pandemic affecting pig production worldwide. Except in Vietnam, where two vaccines were recently approved for controlled use in the field, no vaccine is commercially available for disease control. Up to now, the most effective vaccines developed are based on the use of live-attenuated viruses. Most of these promising vaccine candidates were developed by deleting virus genes involved in the process of viral pathogenesis and disease production. Therefore, these vaccine candidates were developed via the genomic modification of parental virus field strains, producing recombinant viruses and reducing or eliminating their residual virulence. In this scenario, it is critical to confirm the absence of any residual virulence in the vaccine candidate. This report describes the assessment of the presence of residual virulence in the ASFV vaccine candidate ASFV-G-∆I177L in clinical studies conducted under high virus loads and long-term observation periods. The results demonstrated that domestic pigs intramuscularly inoculated with 10 HAD of ASFV-G-∆I177L did not show the presence of any clinical sign associated with ASF when observed daily either 90 or 180 days after vaccination. In addition, necropsies conducted at the end of the experiment confirmed the absence of macroscopic internal lesions associated with the disease. These results corroborate the safety of using ASFV-G-∆I177L as a vaccine candidate.
非洲猪瘟（ASF）是目前猪类中的一种重要疾病，正在全球范围内引发一场影响生猪生产的大流行。除了越南，该国最近批准了两种疫苗可在田间进行受控使用外，尚无用于疾病控制的商业疫苗。到目前为止，开发出的最有效的疫苗是基于使用减毒活病毒。这些有前景的候选疫苗大多是通过删除参与病毒发病机制和疾病产生过程的病毒基因而开发的。因此，这些候选疫苗是通过对亲本病毒田间毒株进行基因组改造而开发的，产生重组病毒并降低或消除其残余毒力。在这种情况下，确认候选疫苗中不存在任何残余毒力至关重要。本报告描述了在高病毒载量和长期观察期的临床研究中，对非洲猪瘟病毒候选疫苗ASFV-G-∆I177L中残余毒力的评估。结果表明，接种10个猪感染剂量（HAD）的ASFV-G-∆I177L的家猪，在接种疫苗后90天或180天每天观察时，未表现出与非洲猪瘟相关的任何临床症状。此外，实验结束时进行的尸检证实不存在与该疾病相关的肉眼可见的内部病变。这些结果证实了使用ASFV-G-∆I177L作为候选疫苗的安全性。
