Characterization of single-domain antibodies against Foot and Mouth Disease Virus (FMDV) serotype O from a camelid and imaging of FMDV in baby hamster kidney-21 cells with single-domain antibody-quantum dots probes.

Di Wang,Youjun Shang,Xiangtao Liu,Jianping Cai,Jijun He,Jianhong Guo,Shunli Yang,Shuanghui Yin,Ping Du

doi:10.1186/s12917-015-0437-2

Abstract

BackgroundFoot-and-mouth disease (FMD) is a highly contagious disease that affects cloven-hoofed animals and causes significant economic losses to husbandry worldwide. The variable domain of heavy-chain antibodies (VHHs or single domain antibodies, sdAbs) are single-domain antigen-binding fragments derived from camelid heavy-chain antibodies.ResultsIn this work, two sdAbs against FMD virus (FMDV) serotype O were selected from a camelid phage display immune library and expressed in Escherichia coli. The serotype specificity and affinity of the sdAbs were identified through enzyme-linked immunosorbent assay and surface plasmon resonance assay. Moreover, the sdAbs were conjugated with quantum dots to constitute probes for imaging FMD virions. Results demonstrated that the two sdAbs were specific for serotype O and shared no cross-reactivity with serotypes A and Asia 1. The equilibrium dissociation constant (KD) values of the two sdAbs ranged from 6.23 nM to 8.24 nM, which indicated high affinity to FMDV antigens. Co-localization with the sdAb-AF488 and sdAb-QD probes indicated the same location of FMDV virions in baby hamster kidney-21 (BHK-21) cells.ConclusionssdAb-QD probes are powerful tools to detect and image FMDV in BHK-21 cells.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-015-0437-2) contains supplementary material, which is available to authorized users.

Highlights

Foot-and-mouth disease (FMD) is a highly contagious disease that affects cloven-hoofed animals and causes significant economic losses to husbandry worldwide
We investigated the possibility of constructing Single-domain antibody (sdAb)-Quantum dot (QD) probes for imaging FMD virus (FMDV) in Baby hamster kidney (BHK)-21 cells
Camelus bactrianus immunization and antibody detection Two C. bactrianus were vaccinated with 2 mL of inactivated FMDV serotype O vaccine (107 50 % TCID50/mL) emulsified in Montanide ISA 206 (ISA) in accordance with previously described methods [18]

Summary

Introduction

Foot-and-mouth disease (FMD) is a highly contagious disease that affects cloven-hoofed animals and causes significant economic losses to husbandry worldwide. The N-terminal domains of the H and L polypeptide chains are responsible for antigen recognition Apart from these conventional antibodies, naturally occurring and functional antibodies that are devoid of light chains are found in the sera of camelids [5] and a cartilaginous fish [6]. These special antibodies, known as heavy chain antibodies (HCAbs), lack the first constant domain. These antibodies have various medical and biotechnological applications, such as in cancer therapy [11, 12]

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