During an ongoing outbreak of Foot-and-Mouth Disease Virus (FMDV), it is crucial to distinguish naturally infected from vaccinated seropositive animals. This would support clinical assessment and punctual vigilance. Assays based on 3ABC non-structural protein as an antigen are reliable for this intention. However, the insolubility and degradation of recombinant 3ABC during expression and purification are serious challenges. In this study, alternatively to expressing the recombinant 3ABC (r3ABC), we expressed the 3AB coding sequence (~672 bp) as a recombinant protein (r3AB) with a molecular mass of ~26 KDa. Analytical data from three-dimensional structure, hydrophilicity, and antigenic properties for 3ABC and 3AB exhibited the 3C protein as a hydrophobic, while 3AB as a hydrophilic and highly antigenic protein. The expressed r3AB was recovered as a completely soluble matter after merely native purification, unlike the full expressed r3ABC. Immunoreactivity of r3AB to anti-FMDV antibody in infected sera with different FMDV serotypes was confirmed by the western blot and indirect ELISA. Besides, the authentic antigenicity of purified r3AB was demonstrated through its ability to induce specific seroconversion in mice. Summarily, the removal of 3C: has influenced neither 3D structure nor antigenic properties of the purified r3AB, overcame insolubility and degradation of the r3ABC, and generated a potential superior antigen (r3AB) for herd screening of animals to any FMDV serotype.

在口蹄疫病毒 (FMDV) 持续爆发期间，区分自然感染动物和已接种疫苗的血清阳性动物至关重要。这将支持临床评估和准时警惕。基于 3ABC 非结构蛋白作为抗原的测定对于此目的是可靠的。然而，重组3ABC在表达和纯化过程中的不溶性和降解是严峻的挑战。在本研究中，除了表达重组 3ABC (r3ABC) 之外，我们还将 3AB 编码序列 (~672 bp) 表达为重组蛋白 (r3AB)，分子量约为 26 KDa。 3ABC和3AB的三维结构、亲水性和抗原特性的分析数据显示3C蛋白是疏水性的，而3AB是亲水性和高抗原性的蛋白。与完全表达的r3ABC不同，表达的r3AB仅在天然纯化后就以完全可溶的物质形式回收。通过蛋白质印迹和间接 ELISA 证实了不同 FMDV 血清型感染血清中 r3AB 与抗 FMDV 抗体的免疫反应性。此外，纯化的 r3AB 的真实抗原性通过其在小鼠中诱导特异性血清转化的能力得到证明。总之，去除 3C：既不影响纯化的 r3AB 的 3D 结构，也不影响其抗原特性，克服了 r3ABC 的不溶性和降解性，并产生了一种潜在的优质抗原 (r3AB)，用于针对任何 FMDV 血清型对动物进行群体筛选。