The Pirbright Institute, Pirbright, Woking GU24 0NF, UK.
Department of Pathology and Infectious Diseases, Faculty of Health and Medical Sciences, School of Veterinary Medicine, University of Surrey, Guilford GU2 7AL, UK.
Viruses. 2022 Mar 29;14(4):714. doi: 10.3390/v14040714.
Foot-and-mouth disease (FMD) is a disease of cloven-hoofed livestock caused by FMD virus (FMDV). FMD can be controlled through the use of inactivated vaccines, and it is well established that the protection afforded by FMD vaccines correlates strongly with neutralising antibody titres. However, the overall strength of binding, referred to as avidity, is also an important parameter with respect to the ability of antibodies to neutralise virus infection, and there is evidence that avidity can affect the level of protection afforded by FMDV vaccines. Here, as an alternative to modified enzyme-linked immunosorbent assays (avidity ELISAs) incorporating a chaotropic wash step, we used bio-layer interferometry (BLI) to measure the avidity of bovine polyclonal antibodies against FMDV capsids. We conducted preliminary experiments using recombinant FMDV capsids, as well as peptides representing antigenic loops, to demonstrate that the binding of monoclonal antibodies targeting specific antigenic sites could be detected using BLI. Subsequent experiments using polyclonal sera derived from FMD vaccinated cattle provided evidence of a positive correlation between the neutralising titre of the serum and the avidity as measured by BLI. Furthermore, we observed an increase in BLI avidity, as well as in the titre, in vaccinated animals upon challenge with the live virus.
口蹄疫（FMD）是一种由口蹄疫病毒（FMDV）引起的偶蹄动物疾病。可以通过使用灭活疫苗来控制 FMD，并且已经证实 FMD 疫苗提供的保护与中和抗体滴度密切相关。然而，整体结合强度，也称为亲和力，对于抗体中和病毒感染的能力也是一个重要参数，有证据表明亲和力可以影响 FMDV 疫苗提供的保护水平。在这里，作为替代包含离液盐洗涤步骤的改良酶联免疫吸附测定（亲和力 ELISA），我们使用生物层干涉测量法（BLI）来测量针对 FMDV 衣壳的牛多克隆抗体的亲和力。我们使用重组 FMDV 衣壳以及代表抗原环的肽进行了初步实验，证明可以使用 BLI 检测针对特定抗原位点的单克隆抗体的结合。随后使用来自 FMD 接种牛的多克隆血清进行的实验提供了证据，表明血清的中和效价与 BLI 测量的亲和力之间存在正相关。此外，我们观察到在活病毒攻击时，接种动物的 BLI 亲和力以及效价均增加。
