Development and application of a high sensitivity immunochromatographic test strip for detecting classical swine fever virus antibody

Classical swine fever (CSF) is caused by classical swine fever virus (CSFV) and has led to huge ecnomic losses for the pig industry worldwide. Although vaccination and other control measures have been carried out, it is essential to establish a rapid and valid method for CSF vaccination monitoring and clinical diagnosis. CSFV E2 protein has been well-known as a major antigen for antibody detection. It is significant to improve affinity between E2 protein and CSFV antibody for a better performance of detection method. In this study, a recombinant E2 extracellular protein (aa 1-331), which has a native homodimer conformation and has a high affinity with anti-CSFV-E2 monoclonal antibody WH303, was expressed using Bac-to-Bac baculovirus expression system. A novel immunochromatographic test strip based on the recombinant CSFV E2 protein was developed for CSFV antibody detection. The sensitivity of this strip for detecting CSFV standard positive serum was 1:102400, 4 times higher than that of the previously developed CnC2 test strip. No cross reaction with antibodies of other swine viruses was observed. The detection of clinical swine serum samples (n=138) demonstrated that the agreements of this E2 test strip with three commercial ELISA kits were 88.40% (122/138), 86.23% (119/138), and 96.38% (133/138), respectively. Our data indicated that a novel E2 test strip with higher sensitivity has been developed and can be applied for clinical sample detections, providing a new powerful and simple approach for CSFV antibody monitoring.

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Development and Application of a High Sensitivity Immunochromatographic Test Strip for Detecting Classical Swine Fever Virus Antibody

10.21203/rs.3.rs-434204/v1 ◽

2021 ◽

Author(s):

Yilin Bai ◽

Rui Jia ◽

Qiang Wei ◽

Li Wang ◽

Yaning Sun ◽

...

Keyword(s):

Classical Swine Fever Virus ◽

Clinical Sample ◽

Expression System ◽

Classical Swine Fever ◽

Test Strip ◽

Fever Virus ◽

Control Measures ◽

Antibody Detection ◽

Immunochromatographic Test ◽

E2 Protein

Abstract Background: Classical swine fever (CSF) is caused by classical swine fever virus (CSFV) and has lead huge losses to the pig industry worldwide. Although vaccination and other control measures have been carried out, it is essential to establish a rapid valid method for CSF vaccination monitoring and clinical diagnosis. CSFV E2 protein has been well known as a major antigen for antibody detection. It is significant to improve affinity between E2 protein and CSFV antibody to result in a better performance of detection method. Results: In this study, a recombinant E2 extracellular protein (aa 1-331), which was with the native homodimer conformation and had a high affinity with anti-CSFV-E2 monoclonal antibody WH303, was expressed using Bac-to-Bac baculovirus expression system. A novel immunochromatographic test strip based on the recombinant CSFV E2 protein was developed for CSFV antibody detection. The sensitivity of this strip for detecting CSFV standard positive serum was 1:102400, 4 times higher than that of the former developed CnC2 test strip. No cross reaction with other swine virus antibodies was observed. The detection of clinical swine serum samples (n=138) demonstrated that the agreement of the new E2 test strip with three commercial ELISA kits was 88.40% (122/138), 86.23% (119/138), and 96.38% (133/138), respectively. Conclusion: Our data indicate that a novel E2 test strip with higher sensitivity has been developed and can be applied for clinical sample detections, providing a new powerful and simple approach for future monitoring CSFV antibodies.

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Development and application of a high‐sensitivity immunochromatographic test strip for detecting classical swine fever virus antibodies

Transboundary and Emerging Diseases ◽

10.1111/tbed.14367 ◽

2021 ◽

Author(s):

Yilin Bai ◽

Rui Jia ◽

Qiang Wei ◽

Li Wang ◽

Yaning Sun ◽

...

Keyword(s):

Classical Swine Fever Virus ◽

Classical Swine Fever ◽

High Sensitivity ◽

Test Strip ◽

Fever Virus ◽

Immunochromatographic Test

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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

Applied and Environmental Microbiology ◽

10.1128/aem.00127-15 ◽

2015 ◽

Vol 81 (11) ◽

pp. 3745-3752 ◽

Cited By ~ 27

Author(s):

Yi-Gang Xu ◽

Xue-Ting Guan ◽

Zhong-Mei Liu ◽

Chang-Yong Tian ◽

Li-Chun Cui

Keyword(s):

Immune Responses ◽

Lactobacillus Plantarum ◽

Classical Swine Fever Virus ◽

Oral Vaccine ◽

Classical Swine Fever ◽

Fever Virus ◽

Economic Losses ◽

E2 Protein ◽

Content Type ◽

Cellular Immune

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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