Inactivated Pseudomonas PE(\u0394III) exotoxin fused to neutralizing epitopes of PEDV S proteins produces a specific immune response in mice

Leqiang Sun,Keji Yan,Huawei Zhang,Yajie Tang,Huanchun Chen

doi:10.1186/s44149-021-00021-9

Abstract

Porcine epidemic diarrhea (PED) caused by the porcine epidemic diarrhea virus (PEDV), is a severe infectious and devastating swine disease that leads to serious economic losses in the swine industry worldwide. An increased number of PED cases caused by variant PEDV have been reported in many countries since 2010. S protein is the main immunogenic protein containing some B-cell epitopes that can induce neutralizing antibodies of PEDV. In this study, the construction, expression and purification of Pseudomonas aeruginosa exotoxin A (PE) without domain III (PEΔIII) as a vector was performed for the delivery of PEDV S-A or S-B. PE(ΔIII) PEDV S-A and PE(ΔIII) PEDV S-B recombinant proteins were confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis. The immunogenicity of PEDV S-A and PEDV S-B subunit vaccines were evaluated in mice. The results showed that PEDV-S-B vaccine could not only induce specific humoral and Th1 type-dominant cellular immune responses, but also stimulate PEDV-specific mucosal immune responses in mice. PEDV-S-B subunit vaccine is a novel candidate mucosal vaccine against PEDV infection.

Highlights

Porcine epidemic diarrhea (PED) caused by the porcine epidemic diarrhea virus (PEDV) is a highly contagious and devastating swine disease that leads to high mortality in piglets as it causes severe diarrhea, vomiting and dehydration (Gerdts and Zakhartchouk 2017; Reveles-Félix et al 2020)
The stimulation index (SI) of PEDV S-A significantly differed among PEDV S-B groups. These results indicated that PEDV S-A and PEDV S-B could induce the proliferation of spleen lymphocytes in vitro
Cytokines play an important regulatory role in various immune reactions. These results demonstrated that PEDV S-B group could induce T helper cells (Th1)-dominant cellular immune responses

Summary

Introduction

Porcine epidemic diarrhea (PED) caused by the porcine epidemic diarrhea virus (PEDV) is a highly contagious and devastating swine disease that leads to high mortality in piglets as it causes severe diarrhea, vomiting and dehydration (Gerdts and Zakhartchouk 2017; Reveles-Félix et al 2020). PEDV S glycoprotein is a major immunogenic protein that induces high levels of neutralizing antibodies (Makadiya et al 2016; Hou et al 2018; Li et al 2018a; Li et al 2018b; Chen et al 2021). To evaluate the specific humoral immunity of mice immunized with the recombinant proteins, indirect ELISA and neutralizing antibody tests were performed.

Results

Conclusion