A Heat-Induced Mutation on VP1 of Foot-and-Mouth Disease Virus Serotype O Enhanced Capsid Stability and Immunogenicity

Abstract

Foot-and-mouth disease (FMD) is a highly contagious viral disease affecting cloven-hoofed animals that cause a significant economic burden globally. Vaccination is the most effective FMD control strategy. However, FMDV particles are prone to dissociate when appropriate physical or chemical conditions are unavailable, such as an incomplete cold chain. Such degraded vaccines result in compromised herd vaccination. Therefore, thermostable FMD particles are needed for use in vaccines. This study generated thermostable FMDV mutants (M3 and M10) by serial passages at high temperature, subsequent amplification, and purification. Both mutants contained an alanine to threonine mutation at position 13 in VP1 (A1013T), although M3 contained 3 additional mutations. The selected mutants showed improved stability and immunogenicity in neutralizing antibody titers, compared with the wild-type (wt) virus. The sequencing analysis and cryo-electron microscopy showed that the mutation of alanine to threonine at the 13th amino acid (aa) in VP1 protein (A1013T) is critical for the capsid stability of FMDV. Virus-like particles (VLPA1013T) containing A1013T also showed significantly improved stability to heat treatment. This study demonstrated that Thr at the 13th amino acid of VP1 could stabilize the capsid of FMDV. Our findings will facilitate the development of a stable vaccine against FMDV serotype O. IMPORTANCE Foot-and-mouth disease (FMD) serotype O is one of the global epidemic serotypes, and cause significant economic loss. Vaccination plays a key role in the prevention and control of FMD. However, the success of vaccination mainly depends on the quality of the vaccine. Here, the thermostable FMDV mutants (M3 and M10) were selected through thermal-screening at high temperatures with improved stability and immunogenicity compared to the wild-type virus. The results of multi-sequence alignment and Cryo-EM analysis showed that the "Thr" substitution at the 13th amino acid in VP1 protein is critical for the capsid stability of FMDV. For thermolabile type O FMDV, this major discovery will aid the development of its thermostable vaccine.

Expression of virus-like particles (VLPs) of foot-and-mouth disease virus (FMDV) using Saccharomyces cerevisiae

“…4 ). These were similar in size to the FMDV viral particle (Dong et al 2021 ; Fry et al 1999 ; Jamal and Belsham 2013 ). These results indicate that in yeast, S. cerevisiae -expressed P1 precursor polyprotein is processed into capsid subunit proteins by co-translated 3C protease and then subsequently assembled into a virion particle.…”

Testing of diagnostic test-systems for detection of antibodies to foot-and-mouth disease virus structural proteins with enzyme-linked immunosorbent assay for their serotype specificity

“…Выравнивание аминокислотных последовательностей белка VP1 вируса ящура разных серотипов выполняли согласно информации, полученной из NCBI и опубликованной в открытой печати [6,8,9,10,11,12,13,14,15] Как видно на рисунке 1, ни одна из представленных тест-систем не обладала 100%-й серотипоспецифичностью при исследовании образцов сыворотки крови животных, полученной на 21-28-й день после вакцинации противоящурной моновакциной из штаммов, указанных в таблице 1. Реакция с гомологичными сыворотками была преобладающей, однако количество перекрестнореагирующих образцов оказалось значительным.…”

“…При деградации капсид также, вероятно, может распадаться на отдельные субъединицы. Поверхностные белки VP1-VP3 несут эпитопы, отвечающие за серотипоспецифичность вируса ящура и выработку вируснейтрализующих антител, в то время как внутренний белок VP4 более консервативен у разных серотипов возбудителя и антитела против эпитопов VP4 не обеспечивают защиту от инфекции [3,6].…”

Self−Assembling Nanovaccine Fused with Flagellin Enhances Protective Effect against Foot−and−Mouth Disease Virus

“…In addition, sera samples were collected at 7, 14, 21, and 28 days post−immunization (dpi). According to a previous report, specific antibody levels were detected with sandwich ELISA [49], and the neutralizing antibody titer was analyzed using a serum neutralization test (SNT) [27]. Lymphocyte proliferation was detected using the CellTiter 96 Aqueous Non−Radioactive Cell Proliferation Assay (Promega, Beijing, China) [26].…”