Mlingo Tendai A M, Theron Jacques, Mokoena Nobalanda B
Onderstepoort Biological Products SOC Ltd., Pretoria, South Africa.
Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa.
J Virol. 2025 Apr 15;99(4):e0013925. doi: 10.1128/jvi.00139-25. Epub 2025 Mar 6.
Control of bluetongue disease is predominantly through vaccination with licensed inactivated or live-attenuated vaccines (LAVs). Manufacturing of LAVs in endemic countries requires formulation with a high number of serotypes for effective protection. Herein, we evaluated a plasmid DNA-based reverse genetics platform for manufacturing a multivalent vaccine. The synthetic vaccine was characterized by a common BTV1 backbone, with exchange of outer capsid proteins. Recombinant South African vaccine serotypes 1, 5, and 14 were rescued by exchanging the VP2 protein on the backbone. BTV6 rescue was achieved following the exchange of VP2 and VP5 proteins. The particle sizes were comparable to commercial vaccines of respective serotypes. BTV1, BTV5, and BTV6 had distinct growth profiles compared to commercial vaccines, while BTV14 was indistinguishable. Stability and shelf-life determination under various storage conditions showed that commercial vaccines were more stable. Formulated antigens were evaluated for vaccine safety and immunogenicity in sheep. Serotyped BTV1 monovalent vaccine was safe, as no clinical signs were observed. Neutralizing antibodies (nAbs) were induced on day 14 and peaked at 32 on day 28. The multivalent synthetic vaccine containing four serotypes elicited BTV6 nAbs from day 21 with a titer of 52, which decreased to 33 by day 42. BTV1 elicited a weak immune response with a titer of 1 on day 42. No nAbs were detected against BTV5 and BTV14. This is a first report comparing reverse genetics-derived antigens with commercial vaccines. Data generated on production yields, stability, and immunogenicity demonstrated that some serotypes can be implemented as novel synthetic vaccines using this platform.IMPORTANCEVaccination is the most effective control strategy for viral diseases that affect livestock. To date, only live-attenuated and inactivated vaccines have been licensed for control of bluetongue (BT). This study demonstrated the use of reverse genetics as a possible platform for BTV vaccine production. Data generated in the study contribute toward the advancement of an alternative manufacturing platform for licensing of BT vaccines. Information on production yields and stability of synthetic vaccines in comparison to the conventional products demonstrated that optimization is required for some serotypes to fully translate the reverse genetics platform for manufacturing the BTV vaccine. The study highlighted the safety and immunogenicity of vaccines manufactured using the plasmid DNA-based reverse-genetics platform.
蓝舌病的防控主要通过接种已获许可的灭活疫苗或减毒活疫苗（LAV）。在流行国家生产LAV需要针对多种血清型进行配方设计，以实现有效保护。在此，我们评估了一种基于质粒DNA的反向遗传学平台用于生产多价疫苗。合成疫苗的特征是具有共同的BTV1骨架，并对外衣壳蛋白进行了交换。通过在骨架上交换VP2蛋白，拯救出了重组南非疫苗血清型1、5和14。在交换VP2和VP5蛋白后实现了BTV6的拯救。颗粒大小与各血清型的商业疫苗相当。与商业疫苗相比，BTV1、BTV5和BTV6具有不同的生长曲线，而BTV14则难以区分。在各种储存条件下进行的稳定性和保质期测定表明，商业疫苗更稳定。对配制好的抗原在绵羊中进行了疫苗安全性和免疫原性评估。血清型为BTV1的单价疫苗是安全的，未观察到临床症状。在第14天诱导出中和抗体（nAb），并在第28天达到峰值32。含有四种血清型的多价合成疫苗在第21天诱导出BTV6 nAb，效价为52，到第42天降至33。BTV1在第42天诱导出微弱的免疫反应，效价为1。未检测到针对BTV5和BTV14的nAb。这是首次将反向遗传学衍生的抗原与商业疫苗进行比较的报告。关于产量、稳定性和免疫原性的数据表明，利用该平台，某些血清型可作为新型合成疫苗应用。重要性接种疫苗是防控影响家畜的病毒性疾病的最有效策略。迄今为止，只有减毒活疫苗和灭活疫苗被许可用于防控蓝舌病（BT）。本研究证明了反向遗传学可作为生产BTV疫苗的一个可能平台。该研究中产生的数据有助于推进BT疫苗许可的替代生产平台。与传统产品相比，关于合成疫苗产量和稳定性的信息表明，对于某些血清型，需要进行优化，以便充分利用反向遗传学平台来生产BTV疫苗。该研究突出了使用基于质粒DNA的反向遗传学平台生产的疫苗的安全性和免疫原性。
