Immunogenicity in Swine of Orally Administered Recombinant Lactobacillus plantarum Expressing Classical Swine Fever Virus E2 Protein in Conjunction with Thymosin α-1 as an Adjuvant

ABSTRACTClassical swine fever, caused by classical swine fever virus (CSFV), is a highly contagious disease that results in enormous economic losses in pig industries. The E2 protein is one of the main structural proteins of CSFV and is capable of inducing CSFV-neutralizing antibodies and cytotoxic T lymphocyte (CTL) activitiesin vivo. Thymosin α-1 (Tα1), an immune-modifier peptide, plays a very important role in the cellular immune response. In this study, genetically engineeredLactobacillus plantarumbacteria expressing CSFV E2 protein alone (L. plantarum/pYG-E2) and in combination with Tα1 (L. plantarum/pYG-E2-Tα1) were developed, and the immunogenicity of each as an oral vaccine to induce protective immunity against CSFV in pigs was evaluated. The results showed that recombinantL. plantarum/pYG-E2 andL. plantarum/pYG-E2-Tα1 were both able to effectively induce protective immune responses in pigs against CSFV infection by eliciting immunoglobulin A (IgA)-based mucosal, immunoglobulin G (IgG)-based humoral, and CTL-based cellular immune responses via oral vaccination. Significant differences (P< 0.05) in the levels of immune responses were observed betweenL. plantarum/pYG-E2-Tα1 andL. plantarum/pYG-E2, suggesting a better immunogenicity ofL. plantarum/pYG-E2-Tα1 as a result of the Tα1 molecular adjuvant that can enhance immune responsiveness and augment specific lymphocyte functions. Our data suggest that the recombinantLactobacillusmicroecological agent expressing CSFV E2 protein combined with Tα1 as an adjuvant provides a promising strategy for vaccine development against CSFV.

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Crystal Structure of Classical Swine Fever Virus NS5B Reveals a Novel N-Terminal Domain

Journal of Virology ◽

10.1128/jvi.00324-18 ◽

2018 ◽

Vol 92 (14) ◽

Cited By ~ 5

Author(s):

Weiwei Li ◽

Baixing Wu ◽

Wibowo Adian Soca ◽

Lei An

Keyword(s):

Crystal Structure ◽

Rna Polymerase ◽

Classical Swine Fever Virus ◽

Classical Swine Fever ◽

Fever Virus ◽

Structural Basis ◽

Economic Losses ◽

Rna Dependent Rna Polymerase ◽

Content Type ◽

Terminal Domain

ABSTRACTClassical swine fever virus (CSFV) is the cause of classical swine fever (CSF). Nonstructural protein 5B (NS5B) is an RNA-dependent RNA polymerase (RdRp) that is a key enzyme initiating viral RNA replication by ade novomechanism. It is also an attractive target for the development of anti-CSFV drugs. To gain a better understanding of the mechanism of CSFV RNA synthesis, here, we solved the first crystal structure of CSFV NS5B. Our studies show that the CSFV NS5B RdRp contains the characteristic finger, palm, and thumb domains, as well as a unique N-terminal domain (NTD) that has never been observed. Mutagenesis studies on NS5B validated the importance of the NTD in the catalytic activity of this novel RNA-dependent RNA polymerase. Moreover, our results shed light on CSFV infection.IMPORTANCEPigs are important domesticated animals. However, a highly contagious viral disease named classical swine fever (CSF) causes devastating economic losses. Classical swine fever virus (CSFV), the primary cause of CSF, is a positive-sense single-stranded RNA virus belonging to the genusPestivirus, familyFlaviviridae. Genome replication of CSFV depends on an RNA-dependent RNA polymerase (RdRp) known as NS5B. However, the structure of CSFV NS5B has never been reported, and the mechanism of CSFV replication is poorly understood. Here, we solve the first crystal structure of CSFV NS5B and analyze the functions of the characteristic finger, palm, and thumb domains. Additionally, our structure revealed the presence of a novel N-terminal domain (NTD). Biochemical studies demonstrated that the NTD of CSFV NS5B is very important for RdRp activity. Collectively, our studies provide a structural basis for future rational design of anti-CSFV drugs, which is critically important, as no effective anti-CSFV drugs have been developed.

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Induction of immune responses in mice and pigs by oral administration of classical swine fever virus E2 protein expressed in rice calli

Archives of Virology ◽

10.1007/s00705-014-2182-4 ◽

2014 ◽

Vol 159 (12) ◽

pp. 3219-3230 ◽

Cited By ~ 4

Author(s):

Myunghwan Jung ◽

Yun Ji Shin ◽

Ju Kim ◽

Seung-Bin Cha ◽

Won-Jung Lee ◽

...

Keyword(s):

Immune Responses ◽

Oral Administration ◽

Classical Swine Fever Virus ◽

Classical Swine Fever ◽

Fever Virus ◽

E2 Protein ◽

Rice Calli

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Gold nanoparticles enhance immune responses in mice against recombinant classical swine fever virus E2 protein

Biotechnology Letters ◽

10.1007/s10529-020-02853-w ◽

2020 ◽

Vol 42 (7) ◽

pp. 1169-1180 ◽

Cited By ~ 1

Author(s):

Yafei Li ◽

Qianyue Jin ◽

Peiyang Ding ◽

Wen Zhou ◽

Yongxiao Chai ◽

...

Keyword(s):

Gold Nanoparticles ◽

Immune Responses ◽

Classical Swine Fever Virus ◽

Classical Swine Fever ◽

Fever Virus ◽

E2 Protein

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Development of whole-porcine monoclonal antibodies with potent neutralization activity against classical swine fever virus (CSFV) from single B cells

10.1101/389361 ◽

2018 ◽

Author(s):

Haisi Dong ◽

Dongmei Lv ◽

Ang Su ◽

Lerong Ma ◽

Jianwei Dong ◽

...

Keyword(s):

Monoclonal Antibodies ◽

B Cells ◽

Virus Infection ◽

Classical Swine Fever Virus ◽

Classical Swine Fever ◽

Fever Virus ◽

Economic Losses ◽

E2 Protein ◽

Neutralizing Activity

AbstractClassical swine fever (CSF) is a highly contagious swine disease found worldwide that has caused devastating economic losses. However, there are few efficacious mAbs against the CSF virus (CSFV) that can be used for treatment because most mAbs against CSFV are derived from mouse hybridoma cells and these murine mAbs have disadvantages of inefficient effector functions elicitations and high immunogenicity in vivo. Accordingly, we characterized whole-porcine anti-CSFV neutralizing mAbs (NAbs) isolated directly from single B cells sorted from a CSFV-vaccinated pig using the fluoresceinated conserved linear neutralizing epitope of the CSFV E2 protein and fluorophore conjugated goat anti-pig IgG. Immunoglobulin (Ig) genes were isolated via nested PCR, and two porcine mAbs termed HK24 and HK44 were produced. We determined that these mAbs can bind to E2 protein and recognize sites within this major antigenic epitope. In addition, we found that mAbs HK24 and HK44 exhibit potent neutralizing activity against CSFV, and they can protect PK-15 cells from infections in vitro with potent IC50 values of 9.3 μg/ml and 0.62 μg/ml, respectively. Notably, we demonstrated that these two mAbs can be used as novel reagents for detecting virus infection. These data suggest that our results not only provide a method for efficiently obtaining mAbs against CSFV but also offer promising mAb candidates for development of antibody-based diagnostic and antiviral agents.ImportanceNeutralizing monoclonal antibodies (NAbs) can prevent and may slow the spread of virus infection. The discovery of NAbs that recognize classical swine fever virus (CSFV) necessitates new technologies because the NAbs produced by immunization and hybridoma technology could not be transferred to in vivo research. Multiple full-length human therapeutic antibodies have been produced via single-cell polymerase chain reactions but whole-porcine NAbs for CSFV have not been generated. In this study, two whole-porcine mAbs, named HK24 and HK44, were isolated from epitope-specific single B cells. We demonstrate that these two mAbs have potent neutralizing activity against CSFV and can protect cells against viral infection. Therefore, they may facilitate the development of vaccines or antiviral drugs that offer the advantages of stability and low immunogenicity.

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Immune responses induced by a BacMam virus expressing the E2 protein of classical swine fever virus in mice

Immunology Letters ◽

10.1016/j.imlet.2009.07.001 ◽

2009 ◽

Vol 125 (2) ◽

pp. 145-150 ◽

Cited By ~ 13

Author(s):

Miao Li ◽

Yu-Fei Wang ◽

Yu Wang ◽

Hui Gao ◽

Na Li ◽

...

Keyword(s):

Immune Responses ◽

Classical Swine Fever Virus ◽

Classical Swine Fever ◽

Fever Virus ◽

E2 Protein

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Immunogenicity of Recombinant Classic Swine Fever Virus CD8+T Lymphocyte Epitope and Porcine Parvovirus VP2 Antigen Coexpressed by Lactobacillus casei in Swine via Oral Vaccination

Clinical and Vaccine Immunology ◽

10.1128/cvi.05204-11 ◽

2011 ◽

Vol 18 (11) ◽

pp. 1979-1986 ◽

Cited By ~ 26

Author(s):

Yigang Xu ◽

Lichun Cui ◽

Changyong Tian ◽

Guocai Zhang ◽

Guicheng Huo ◽

...

Keyword(s):

T Lymphocyte ◽

Cytotoxic T Lymphocyte ◽

Oral Vaccine ◽

Classical Swine Fever ◽

Genetically Engineered ◽

Fever Virus ◽

Economic Losses ◽

Porcine Parvovirus ◽

Content Type ◽

Cd8 T Lymphocyte

ABSTRACTClassical swine fever virus (CSFV) and porcine parvovirus (PPV) are highly contagious pathogens, resulting in enormous economic losses in pig industries worldwide. Because vaccines play an important role in disease control, researchers are seeking improved vaccines that could induce antiviral immune responses against CSFV and PPV at the mucosal and systemic levels simultaneously. In this study, a genetically engineeredLactobacillusstrain coexpressing the CSFV-specific cytotoxic T lymphocyte (CTL) epitope 290 and the VP2 antigen of PPV was developed, and its immunopotentiating capacity as an oral vaccine in pigs was analyzed. The data demonstrated that in the absence of any adjuvant, the recombinantLactobacillusstrain can efficiently stimulate mucosal and systemic CSFV-specific CD8+CTL responses to protect pigs against CSFV challenge. Moreover, anti-PPV-VP2 serum IgG and mucosal IgA were induced in pigs immunized orally with the recombinantLactobacillusstrain, showing a neutralizing effect on PPV infection. The results suggest that the recombinantLactobacillusmicroecological agent may be a valuable component of a strategy for development of a vaccine against CSFV and PPV.

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Humoral and cellular immune response in mice induced by the classical swine fever virus E2 protein fused to the porcine CD154 antigen

Biologicals ◽

10.1016/j.biologicals.2017.12.004 ◽

2018 ◽

Vol 52 ◽

pp. 67-71 ◽

Cited By ~ 1

Author(s):

Yusmel Sordo ◽

Marisela Suárez ◽

Rosalina Caraballo ◽

Talía Sardina ◽

Emma Brown ◽

...

Keyword(s):

Immune Response ◽

Classical Swine Fever Virus ◽

Cellular Immune Response ◽

Classical Swine Fever ◽

Fever Virus ◽

E2 Protein ◽

Cellular Immune

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Identification of E2 with improved secretion and immunogenicity against CSFV in piglets

10.21203/rs.2.18234/v2 ◽

2020 ◽

Author(s):

Huiling Xu ◽

Yanli Wang ◽

Guangwei Han ◽

Weihuan Fang ◽

fang he

Keyword(s):

Single Dose ◽

Signal Peptide ◽

Classical Swine Fever Virus ◽

Subunit Vaccine ◽

Classical Swine Fever ◽

Cost Effective ◽

Fever Virus ◽

Economic Losses ◽

Swine Industry ◽

Virus Challenge

Abstract Background: Outbreaks of Classical swine fever virus (CSFV) cause significant economic losses in the swine industry. Vaccination is the major method to prevent and control the disease. As live attenuated vaccines fail to elicit differentiable immunity between infected and vaccinated animals, subunit vaccine was considered as an alternative candidate to prevent and eradicate CSFV. Subunit vaccines present advantages in DIVA immunogenicity and safety. The technology was limited due to the low yield and the high cost with multiple and large doses. The native E2 signal peptide has not been well defined before. Here, the aim of this study is to develop a cost-effective and efficacious E2 vaccine candidate against CSFV with signal peptide and E2 sequence selection. Results: A novel CSFV E2 sequence (E2ZJ) was identified from an epidemic strain of Zhejiang for outstanding secretion in baculovirus and enhanced immunogenicity. E2 secretion induced with the selected signal peptide, SPZJ (SP23), increase at least 50% as compared to any other signal peptides tested. Besides, unique antigenic features were identified in E2ZJ. E2ZJ elicited CSFV antibodies at the earlier stage than other E2 types tested in mice. Moreover, higher level of neutralization antibodies against both genotypes 1 and 2 CSFV with E2ZJ was detected than other E2s with the same dosage. Further, in piglets, E2ZJ successfully elicited neutralizing immunity. A single dose of 5 μg of E2ZJ was sufficient to induce protective antibodies against CSFV in piglets and provided 100% protection against lethal virus challenge. Conclusions: Our studies provide evidence that E2ZJ guided by a novel E2 signal peptide (SPZJ) was efficiently secreted and presented significantly improved immunogenicity than conventional E2 vaccines. Moreover, a single dose of 5 μg E2ZJ is efficacious against CSFV in piglets. Keywords: Classical swine fever virus; novel signal peptide; SPZJ-E2ZJ; subunit vaccine; protective immunity

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