Fc-Mediated E2-Dimer Subunit Vaccines of Atypical Porcine Pestivirus Induce Efficient Humoral and Cellular Immune Responses in Piglets.

Xujiao Ren,Xiangmin Li,Huanchun Chen,Shudan Liu,Ping Qian

doi:10.3390/v13122443

Abstract

Congenital tremor (CT) type A-II in piglets is caused by an emerging atypical porcine pestivirus (APPV), which is prevalent in swine herds and a serious threat to the pig production industry. This study aimed to construct APPV E2 subunit vaccines fused with Fc fragments and evaluate their immunogenicity in piglets. Here, APPV E2Fc and E2ΔFc fusion proteins expressed in Drosophila Schneider 2 (S2) cells were demonstrated to form stable dimers in SDS-PAGE and western blotting assays. Functional analysis revealed that aE2Fc and aE2ΔFc fusion proteins could bind to FcγRI on antigen-presenting cells (APCs), with the affinity of aE2Fc to FcγRI being higher than that of aE2ΔFc. Moreover, subunit vaccines based on aE2, aE2Fc, and aE2ΔFc fusion proteins were prepared, and their immunogenicity was evaluated in piglets. The results showed that the Fc fusion proteins emulsified with the ISA 201VG adjuvant elicited stronger humoral and cellular immune responses than the IMS 1313VG adjuvant. These findings suggest that APPV E2 subunit vaccines fused with Fc fragments may be a promising vaccine candidate against APPV.

Highlights

The supernatants derived from Schneider 2 (S2) cells were analyzed via western blotting using anti-His monoclonal antibodies
To determine whether the Fc fusion protein can increase its ability to bind to its receptor FcγRI, we identified the binding of atypical porcine pestivirus (APPV) E2Fc and E2ΔFc fusion proteins to FcγRI
To determine whether the Fc fusion protein can increase its ability to bind to its receptor FcγRI, we identified the binding of APPV E2Fc and E2∆Fc fusion proteins to

Summary

Introduction

Affected piglets show clinical symptoms, including rhythmic tremors in the limbs and head and paroxysmal spasm, further complicated by ataxia. This condition results in decreased suckling ability of piglets, leading to starvation due to insufficient colostrum intake and eventual death. CT type A-II, a disease prevalent in the pig breeding industry, has been proven to be caused by a newly emerging virus called atypical porcine pestivirus (APPV) [3,4]. Other viruses, including astrovirus, lateral-shaking inducing neurodegenerative agent (LINDA) virus, porcine circovirus-like virus P1, and porcine teschovirus (PTV) [5,6,7,8] have been detected in CT-affected piglets by metagenomic sequencing, but only APPV has been confirmed worldwide and has been proven to fulfill

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