Antigenicity and Immunogenicity Analysis of the E. coli Expressed FMDV Structural Proteins; VP1, VP0, VP3 of the South African Territories Type 2 Virus.

Qian Li,Yongguang Zhang,Yang Wang,Ashenafi Wubshet,Anna Szczotka-Bochniarz,Guoxiu Li,Susan Szathmary,Jie Zhang,Yaozhong Ding,Bing Ma,Qian Hou,Junfei Dai,Jiao Chen

doi:10.3390/v13061005

Abstract

An alternative vaccine design approach and diagnostic kits are highly required against the anticipated pandemicity caused by the South African Territories type 2 (SAT2) Foot and Mouth Disease Virus (FMDV). However, the distinct antigenicity and immunogenicity of VP1, VP0, and VP3 of FMDV serotype SAT2 are poorly understood. Similarly, the particular roles of the three structural proteins in novel vaccine design and development remain unexplained. We therefore constructed VP1, VP0, and VP3 encoding gene (SAT2:JX014256 strain) separately fused with His-SUMO (histidine-small ubiquitin-related modifier) inserted into pET-32a cassette to express the three recombinant proteins and separately evaluated their antigenicity and immunogenicity in mice. The fusion protein was successfully expressed and purified by the Ni-NTA resin chromatography. The level of serum antibody, spleen lymphocyte proliferation, and cytokines against the three distinct recombinant proteins were analyzed. Results showed that the anti-FMDV humoral response was triggered by these proteins, and the fusion proteins did enhance the splenocyte immune response in the separately immunized mice. We observed low variations among the three fusion proteins in terms of the antibody and cytokine production in mice. Hence, in this study, results demonstrated that the structural proteins of SAT2 FMDV could be used for the development of immunodiagnostic kits and subunit vaccine designs.

Highlights

Our results indicated that the recombinant proteins of HisSumo-VP1 and HisSumo-VP3 were expressed into soluble form and purified by Ni-NTA
The results showed that the spleen lymphocytes of mice immunized with the three fusion proteins display a higher proliferation compared to the PBS group and the His-small ubiquitin-like modifier (SUMO) group
The results showed that the three fusion proteins had good antigenicity and immunogenicity compared to the control groups, which could induce effective humoral and cellular immune responses in mice

Summary

Introduction

The single-stranded positive-sense RNA genome of Foot and Mouth Disease Virus (FMDV) [1] contains a large single open reading frame (ORF) post translated into structural polyproteins (VP1, VP2, VP3, and VP4) and non-structural proteins (Lab, Lb, 2A, 2B, 2C, 3A, 3B, 3C, and 3D) [2]. The structural proteins of FMDV are responsible for the assembly of viral capsids, maintenance of viral stability, binding of cells, determination of antigen specificity, and play a key role in viral infection and recognition [3]. Except for VP4, which forms the inner part of the capsid, VP1, VP2, and VP3 are partially exposed on the capsid surface [3]. The fundamental structures of VP1, VP2, and VP3 are grossly similar [4]

Methods

Results

Discussion

Conclusion