Foot-and-mouth disease (FMD) is a significant threat to animal health globally. Prophylactic vaccination using inactivated FMD virus (FMDV) antigen is being practised for the control in endemic countries. A major limitation of the current vaccine is its susceptibility to high environmental temperature causing loss of immunogenicity, thus necessitating the cold chain for maintenance of its efficacy. Hence, the FMD vaccine with thermostable virus particles will be highly useful in sustaining the integrity of whole virus particle (146S) during storage at 4°C. In this study, 12 recombinant mutants of Indian vaccine strain of FMDV serotype O (O/IND/R2/1975) were generated through reverse genetics approach and evaluated for thermostability. One of the mutant viruses, VP2_Y98F was more thermostable than other mutants and the parent FMDV. The oil-adjuvanted vaccine formulated with the inactivated VP2_Y98F mutant FMDV was stable up to 8 months when stored at 4°C and induced protective antibody response till dpv 180 after primary vaccination. It is concluded that the VP2_Y98F mutant FMDV was thermostable and has the potential to replace the parent vaccine strain.

中文翻译：

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印度口蹄疫病毒血清型 O 疫苗株 VP2 蛋白中的单个氨基酸取代赋予牛热稳定性和保护性免疫力

口蹄疫 (FMD) 是对全球动物健康的重大威胁。使用灭活口蹄疫病毒 (FMDV) 抗原的预防性疫苗接种正在流行国家进行控制。目前疫苗的一个主要限制是它对高温环境的敏感性导致免疫原性丧失，因此需要冷链来维持其功效。因此，具有热稳定性病毒颗粒的 FMD 疫苗在 4°C 储存期间对于维持整个病毒颗粒 (146S) 的完整性非常有用。在这项研究中，通过反向遗传学方法生成了 12 个印度口蹄疫疫苗株 O 血清型 (O/IND/R2/1975) 的重组突变体，并评估了热稳定性。其中一种突变病毒 VP2_Y98F 比其他突变病毒和亲本 FMDV 更耐热。用灭活的 VP2_Y98F 突变体 FMDV 配制的油佐剂疫苗在 4°C 下储存时可稳定长达 8 个月，并在初次接种后诱导保护性抗体反应直至 dpv 180。结论是VP2_Y98F突变体FMDV具有耐热性，具有替代亲本疫苗株的潜力。