FMD Vaccine Research Laboratory, ICAR-Indian Veterinary Research Institute, Hebbal, Bengaluru, 560 024, India.
Directorate of Foot and Mouth Disease, ICAR-International Centre for FMD, Bhubaneswar, 752 050, India.
Appl Microbiol Biotechnol. 2023 Feb;107(4):1285-1297. doi: 10.1007/s00253-023-12359-w. Epub 2023 Jan 19.
Foot-and-mouth disease (FMD) is a contagious viral disease of high economic importance, caused by FMD virus (FMDV), a positive-sense single-stranded RNA virus, affecting cloven-hoofed animals. Preventive vaccination using inactivated virus is in practice to control the disease in many endemic countries. While the vaccination induces antibodies mainly to structural proteins, the presence of antibodies to the non-structural proteins (NSP) is suggestive of infection, a criterion for differentiation of infected from vaccinated animals (DIVA). Also, there is a growing demand for enhancing the stability of the FMD vaccine virus capsid antigen as the strength of the immune response is proportional to the amount of intact 146S particles in the vaccine. Considering the need for a DIVA compliant stable vaccine, here we report generation and rescue of a thermostable and negative marker virus FMDV serotype O (IND/R2/1975) containing a partial deletion in non-structural protein 3A, generated by reverse genetics approach. Immunization of guinea pigs with the inactivated thermostable-negative marker virus antigen induced 91% protective immune response. Additionally, a companion competitive ELISA (cELISA) targeting the deleted 3A region was developed, which showed 92.3% sensitivity and 97% specificity, at cut-off value of 36% percent inhibition. The novel thermostable-negative marker FMDV serotype O vaccine strain and the companion cELISA could be useful in FMDV serotype O enzootic countries to benefit the FMD control program. KEY POINTS: • Thermostable foot-and-mouth disease virus serotype O with partial deletion in 3A. • Inactivated thermostable marker vaccine induced 91% protection in guinea pigs. • Companion cELISA based on deleted region in 3A could potentially facilitate DIVA.
口蹄疫（FMD）是一种具有高度经济重要性的传染性病毒性疾病，由口蹄疫病毒（FMDV）引起，FMDV 是一种正链单链 RNA 病毒，影响偶蹄动物。在许多流行国家，使用灭活病毒进行预防接种是控制该病的方法。虽然疫苗接种主要诱导针对结构蛋白的抗体，但存在针对非结构蛋白（NSP）的抗体提示感染，这是区分感染动物和接种疫苗动物（DIVA）的标准。此外，由于免疫反应的强度与疫苗中完整 146S 颗粒的数量成正比，因此对手足口病疫苗病毒衣壳抗原的稳定性提出了更高的要求。考虑到需要符合 DIVA 的稳定疫苗，本研究通过反向遗传学方法报告了口蹄疫病毒血清型 O（IND/R2/1975）耐热和负标记病毒的产生和拯救，该病毒在非结构蛋白 3A 中存在部分缺失。用灭活耐热负标记病毒抗原对豚鼠进行免疫接种可诱导 91%的保护性免疫反应。此外，还开发了针对缺失 3A 区的伴随竞争性 ELISA（cELISA），其在 36%抑制率的截断值下显示出 92.3%的敏感性和 97%的特异性。新型耐热负标记口蹄疫病毒血清型 O 疫苗株和伴随的 cELISA 可用于口蹄疫病毒血清型 O 流行国家，对口蹄疫控制计划有益。关键点：• 具有 3A 部分缺失的耐热口蹄疫病毒血清型 O。• 灭活耐热标记疫苗在豚鼠中诱导 91%的保护。• 基于 3A 缺失区的伴随 cELISA 可能有助于 DIVA。
