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Characterization of monoclonal antibodies that specifically differentiate field isolates from vaccine strains of classical swine fever virus

Classical swine fever virus (CSFV) is a major animal pathogen threatening the global pork industry. To date, numerous anti-CSFV monoclonal antibodies (mAbs) and their recognizing epitopes have been reported. However, few mAbs were systematically characterized for the capacity to differentiate field...

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Autores principales: Mi, Shijiang, Wang, Lihua, Li, Hongwei, Bao, Fei, Madera, Rachel, Shi, Xiju, Zhang, Liying, Mao, Yingying, Yan, Renhe, Xia, Xianzhu, Gong, Wenjie, Shi, Jishu, Tu, Changchun
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9361847/
https://www.ncbi.nlm.nih.gov/pubmed/35958565
http://dx.doi.org/10.3389/fimmu.2022.930631
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author Mi, Shijiang
Wang, Lihua
Li, Hongwei
Bao, Fei
Madera, Rachel
Shi, Xiju
Zhang, Liying
Mao, Yingying
Yan, Renhe
Xia, Xianzhu
Gong, Wenjie
Shi, Jishu
Tu, Changchun
author_facet Mi, Shijiang
Wang, Lihua
Li, Hongwei
Bao, Fei
Madera, Rachel
Shi, Xiju
Zhang, Liying
Mao, Yingying
Yan, Renhe
Xia, Xianzhu
Gong, Wenjie
Shi, Jishu
Tu, Changchun
author_sort Mi, Shijiang
collection PubMed
description Classical swine fever virus (CSFV) is a major animal pathogen threatening the global pork industry. To date, numerous anti-CSFV monoclonal antibodies (mAbs) and their recognizing epitopes have been reported. However, few mAbs were systematically characterized for the capacity to differentiate field CSFV isolates from CSF vaccine strains, and the molecular basis associated with antigenic differences between vaccines and field isolates is still largely unknown. In the present study, recombinant CSFV structural glycoproteins E2 of both virulent and vaccine strains and E(rns) of vaccine strain were expressed using eukaryotic cells and murine mAbs generated against E2 and E(rns). After serial screening and cloning of the hybridomas, the viral spectra of mAbs were respectively determined by indirect fluorescent antibody assay (IFA) using 108 CSFVs, followed by Western blot analysis using expressed glycoproteins of all CSFV sub-genotypes including vaccine strains. The antigenic structures recognized by these mAbs were characterized by epitope mapping using truncated, chimeric, and site-directed mutated E2 and E(rns) proteins. We have identified two vaccine-specific, one field isolate-specific, and two universal CSFV-specific mAbs and five novel conformational epitopes with critical amino acid (aa) motifs that are associated with these five mAbs: (213)EPD(215), (271)RXGP(274), and (37)LXLNDG(42) on E2 and (38)CKGVP(42), W(81), and D(100)/V(107) on E(rns). Particularly, E(213) of E2 is field isolate-specific, while N(40) of E2 and D(100)/V(107) of E(rns) are vaccine strain-specific. Results from our study further indicate that N(40)D of E2 mutation in field strains was likely produced under positive selection associated with long-term mass vaccination, leading to CSFV evasion of host immune response. Taking together, this study provides new insights into the antigenic structure of CSFV E2 and E(rns) and the differentiating mAbs will contribute to the development of a diagnostic strategy to differentiate C-strain vaccination from natural infection (DIVA) of CSFV in terms of elimination of CSF in China.
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spelling pubmed-93618472022-08-10 Characterization of monoclonal antibodies that specifically differentiate field isolates from vaccine strains of classical swine fever virus Mi, Shijiang Wang, Lihua Li, Hongwei Bao, Fei Madera, Rachel Shi, Xiju Zhang, Liying Mao, Yingying Yan, Renhe Xia, Xianzhu Gong, Wenjie Shi, Jishu Tu, Changchun Front Immunol Immunology Classical swine fever virus (CSFV) is a major animal pathogen threatening the global pork industry. To date, numerous anti-CSFV monoclonal antibodies (mAbs) and their recognizing epitopes have been reported. However, few mAbs were systematically characterized for the capacity to differentiate field CSFV isolates from CSF vaccine strains, and the molecular basis associated with antigenic differences between vaccines and field isolates is still largely unknown. In the present study, recombinant CSFV structural glycoproteins E2 of both virulent and vaccine strains and E(rns) of vaccine strain were expressed using eukaryotic cells and murine mAbs generated against E2 and E(rns). After serial screening and cloning of the hybridomas, the viral spectra of mAbs were respectively determined by indirect fluorescent antibody assay (IFA) using 108 CSFVs, followed by Western blot analysis using expressed glycoproteins of all CSFV sub-genotypes including vaccine strains. The antigenic structures recognized by these mAbs were characterized by epitope mapping using truncated, chimeric, and site-directed mutated E2 and E(rns) proteins. We have identified two vaccine-specific, one field isolate-specific, and two universal CSFV-specific mAbs and five novel conformational epitopes with critical amino acid (aa) motifs that are associated with these five mAbs: (213)EPD(215), (271)RXGP(274), and (37)LXLNDG(42) on E2 and (38)CKGVP(42), W(81), and D(100)/V(107) on E(rns). Particularly, E(213) of E2 is field isolate-specific, while N(40) of E2 and D(100)/V(107) of E(rns) are vaccine strain-specific. Results from our study further indicate that N(40)D of E2 mutation in field strains was likely produced under positive selection associated with long-term mass vaccination, leading to CSFV evasion of host immune response. Taking together, this study provides new insights into the antigenic structure of CSFV E2 and E(rns) and the differentiating mAbs will contribute to the development of a diagnostic strategy to differentiate C-strain vaccination from natural infection (DIVA) of CSFV in terms of elimination of CSF in China. Frontiers Media S.A. 2022-07-19 /pmc/articles/PMC9361847/ /pubmed/35958565 http://dx.doi.org/10.3389/fimmu.2022.930631 Text en Copyright © 2022 Mi, Wang, Li, Bao, Madera, Shi, Zhang, Mao, Yan, Xia, Gong, Shi and Tu https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Immunology
Mi, Shijiang
Wang, Lihua
Li, Hongwei
Bao, Fei
Madera, Rachel
Shi, Xiju
Zhang, Liying
Mao, Yingying
Yan, Renhe
Xia, Xianzhu
Gong, Wenjie
Shi, Jishu
Tu, Changchun
Characterization of monoclonal antibodies that specifically differentiate field isolates from vaccine strains of classical swine fever virus
title Characterization of monoclonal antibodies that specifically differentiate field isolates from vaccine strains of classical swine fever virus
title_full Characterization of monoclonal antibodies that specifically differentiate field isolates from vaccine strains of classical swine fever virus
title_fullStr Characterization of monoclonal antibodies that specifically differentiate field isolates from vaccine strains of classical swine fever virus
title_full_unstemmed Characterization of monoclonal antibodies that specifically differentiate field isolates from vaccine strains of classical swine fever virus
title_short Characterization of monoclonal antibodies that specifically differentiate field isolates from vaccine strains of classical swine fever virus
title_sort characterization of monoclonal antibodies that specifically differentiate field isolates from vaccine strains of classical swine fever virus
topic Immunology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9361847/
https://www.ncbi.nlm.nih.gov/pubmed/35958565
http://dx.doi.org/10.3389/fimmu.2022.930631
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