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López-Astacio RA, Adu OF, Lee H, Hafenstein SL, Parrish CR. The Structures and Functions of Parvovirus Capsids and Missing Pieces: the Viral DNA and Its Packaging, Asymmetrical Features, Nonprotein Components, and Receptor or Antibody Binding and Interactions. J Virol 2023; 97:e0016123. [PMID: 37367301 PMCID: PMC10373561 DOI: 10.1128/jvi.00161-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2023] Open
Abstract
Parvoviruses are among the smallest and superficially simplest animal viruses, infecting a broad range of hosts, including humans, and causing some deadly infections. In 1990, the first atomic structure of the canine parvovirus (CPV) capsid revealed a 26-nm-diameter T=1 particle made up of two or three versions of a single protein, and packaging about 5,100 nucleotides of single-stranded DNA. Our structural and functional understanding of parvovirus capsids and their ligands has increased as imaging and molecular techniques have advanced, and capsid structures for most groups within the Parvoviridae family have now been determined. Despite those advances, significant questions remain unanswered about the functioning of those viral capsids and their roles in release, transmission, or cellular infection. In addition, the interactions of capsids with host receptors, antibodies, or other biological components are also still incompletely understood. The parvovirus capsid's apparent simplicity likely conceals important functions carried out by small, transient, or asymmetric structures. Here, we highlight some remaining open questions that may need to be answered to provide a more thorough understanding of how these viruses carry out their various functions. The many different members of the family Parvoviridae share a capsid architecture, and while many functions are likely similar, others may differ in detail. Many of those parvoviruses have not been experimentally examined in detail (or at all in some cases), so we, therefore, focus this minireview on the widely studied protoparvoviruses, as well as the most thoroughly investigated examples of adeno-associated viruses.
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Affiliation(s)
- Robert A. López-Astacio
- Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Oluwafemi F. Adu
- Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Hyunwook Lee
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, Pennsylvania, USA
| | - Susan L. Hafenstein
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, Pennsylvania, USA
| | - Colin R. Parrish
- Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
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Novel Epitopes Mapping of African Swine Fever Virus CP312R Protein Using Monoclonal Antibodies. Viruses 2023; 15:v15020557. [PMID: 36851771 PMCID: PMC9963768 DOI: 10.3390/v15020557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 02/10/2023] [Accepted: 02/14/2023] [Indexed: 02/19/2023] Open
Abstract
African Swine Fever (ASF) is a highly contagious and lethal pig disease and poses a huge threat to the pig industry worldwide. ASF virus (ASFV) encodes more than 150 different proteins, but the biological properties of most viral proteins are still unknown. ASFV CP312R protein has been proven to be one of the most immunogenic proteins during ASFV infection in pigs; however, its specific epitopes have yet to be identified. In this study, we verified the immunogenicity of CP312R protein in the sera from attenuated ASFV-inoculated pigs. We generated seven anti-ASFV CP312R mouse monoclonal antibodies (mAbs) from mice immunized with recombinant CP312R protein (rCP312R). All seven mAbs are the IgG2b-Kappa isotype and specifically interacted with the CP312R protein expressed in various cells that were infected by ASFVs or transfected with plasmid CP312R. The epitope mapping was performed by using these characterized mAbs and the peptide scanning (Pepscan) method followed by Western blot. As a result, two antigenic determinant regions were identified: two of the seven mAbs recognized the 122KNEQGEEIYP131 amino acids, and the remaining five mAbs recognized the 78DEEVIRMNAE87 amino acids of the CP312R protein. These antigenic determinants of CP312R are conserved in different ASFV strains of seven genotypes. By using the characterized mAb, confocal microscopy observation revealed that the CP312R was mainly localized in the cytoplasm and, to some extent, in nuclei and on the nuclear membrane of infected host cells. In summary, our results benefit our understanding on the antigenic regions of ASFV CP312R and help to develop better serological diagnosis of ASF and vaccine research.
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Wang Y, Li X, Xu Q, Niu X, Zhang S, Qu X, Chu H, Chen J, Shi Q, Zhang E, Zhang G. Characterization of Neutralizing Monoclonal Antibodies and Identification of a Novel Conserved C-Terminal Linear Epitope on the Hemagglutinin Protein of the H9N2 Avian Influenza Virus. Viruses 2022; 14:v14112530. [PMID: 36423139 PMCID: PMC9698441 DOI: 10.3390/v14112530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/07/2022] [Accepted: 11/10/2022] [Indexed: 11/18/2022] Open
Abstract
The H9N2 avian influenza virus (AIV) remains a serious threat to the global poultry industry and public health. The hemagglutinin (HA) protein is an essential protective antigen of AIVs and a major target of neutralizing antibodies and vaccines. Therefore, in this study, we used rice-derived HA protein as an immunogen to generate monoclonal antibodies (mAbs) and screened them using an immunoperoxidase monolayer assay and indirect enzyme-linked immunosorbent assay. Eight mAbs reacted well with the recombinant H9N2 AIV and HA protein, four of which exhibited potent inhibitory activity against hemagglutination, while three showed remarkable neutralization capacities. Western blotting confirmed that two mAbs bound to the HA protein. Linear epitopes were identified using the mAbs; a novel linear epitope, 480HKCDDQCM487, was identified. Structural analysis revealed that the novel linear epitope is located at the C-terminus of HA2 near the disulfide bond-linked HA1 and HA2. Alignment of the amino acid sequences showed that the epitope was highly conserved among multiple H9N2 AIV strains. The results of this study provide novel insights for refining vaccine and diagnostic strategies and expand our understanding of the immune response against AIV.
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Affiliation(s)
- Yanan Wang
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
- International Associated Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450046, China
| | - Xueyang Li
- International Associated Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450046, China
| | - Qianru Xu
- International Associated Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450046, China
- School of Basic Medical Sciences, Henan University, Kaifeng 475004, China
| | - Xiangxiang Niu
- International Associated Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450046, China
| | - Shenli Zhang
- International Associated Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450046, China
| | - Xiaotian Qu
- International Associated Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450046, China
| | - Hongyan Chu
- International Associated Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450046, China
| | - Jinxuan Chen
- International Associated Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450046, China
| | - Qianqian Shi
- International Associated Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450046, China
| | - Erqin Zhang
- International Associated Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450046, China
- Longhu Modern Immunity Laboratory, Zhengzhou 450046, China
- Correspondence: (E.Z.); (G.Z.)
| | - Gaiping Zhang
- College of Veterinary Medicine, Jilin University, Changchun 130062, China
- International Associated Research Center of National Animal Immunology, College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450046, China
- Longhu Modern Immunity Laboratory, Zhengzhou 450046, China
- School of Advanced Agricultural Sciences, Peking University, Beijing 100871, China
- Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou University, Yangzhou 225000, China
- Correspondence: (E.Z.); (G.Z.)
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Zhou J, Chen J, Peng Y, Xie Y, Xiao Y. A Promising Tool in Serological Diagnosis: Current Research Progress of Antigenic Epitopes in Infectious Diseases. Pathogens 2022; 11:1095. [PMID: 36297152 PMCID: PMC9609281 DOI: 10.3390/pathogens11101095] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 09/20/2022] [Accepted: 09/23/2022] [Indexed: 07/30/2023] Open
Abstract
Infectious diseases, caused by various pathogens in the clinic, threaten the safety of human life, are harmful to physical and mental health, and also increase economic burdens on society. Infections are a complex mechanism of interaction between pathogenic microorganisms and their host. Identification of the causative agent of the infection is vital for the diagnosis and treatment of diseases. Etiological laboratory diagnostic tests are therefore essential to identify pathogens. However, due to its rapidity and automation, the serological diagnostic test is among the methods of great significance for the diagnosis of infections with the basis of detecting antigens or antibodies in body fluids clinically. Epitopes, as a special chemical group that determines the specificity of antigens and the basic unit of inducing immune responses, play an important role in the study of immune responses. Identifying the epitopes of a pathogen may contribute to the development of a vaccine to prevent disease, the diagnosis of the corresponding disease, and the determination of different stages of the disease. Moreover, both the preparation of neutralizing antibodies based on useful epitopes and the assembly of several associated epitopes can be used in the treatment of disease. Epitopes can be divided into B cell epitopes and T cell epitopes; B cell epitopes stimulate the body to produce antibodies and are therefore commonly used as targets for the design of serological diagnostic experiments. Meanwhile, epitopes can fall into two possible categories: linear and conformational. This article reviews the role of B cell epitopes in the clinical diagnosis of infectious diseases.
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Wang A, Tian Y, Liu H, Ding P, Chen Y, Liang C, Du Y, Jiang D, Zhu X, Yin J, Zhang G. Identification of three conserved linear B cell epitopes on the SARS-CoV-2 spike protein. Emerg Microbes Infect 2022; 11:2120-2131. [PMID: 35916768 PMCID: PMC9487943 DOI: 10.1080/22221751.2022.2109515] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Spike (S) glycoproteins is the most significant structural protein of SARS-CoV-2 and a key target for neutralizing antibodies. In light of the ongoing SARS-CoV-2 pandemic, identification and screening of epitopes of spike glycoproteins will provide vital progress in the development of sensitive and specific diagnostic tools. In the present study, NTD, RBD and S2 gene were inserted to the pcDNA3.1(+) vector and designed with N-terminal 6×His-tag for fusion expression in HEK293F cells by transient transfection. Six monoclonal antibodies (4G, 9E, 4B, 7D, 8F, 3D) were prepared using the expressed proteins by cell fusion technique. The characterization of mAbs were performed by indirect -ELISA, western blot and IFA. We designed 49 overlapping synthetized peptides cover the extracellular region of S protein which 6 amino acid residues were offset between adjacent (S1-S49). Peptides S12, S19 and S49 were identified as the immunodominant epitopes regions by the mAbs. These regions were further truncated and the peptides S12.2 286TDAVDCALDPLS297, S19.2 464FERDISTEIYQA475 and S49.4 1202ELGKYEQYIKWP1213 were identified as B- cell linear epitopes for the first time. Alanine scans showed that, the D467, I468, E471, Q474, A475 of the epitope S19.2 and K1205, Q1208, Y1209 of the epitope S49.4 were the core sites involved in the mAbs binding. Multiple sequence alignment analysis showed that these three epitopes were highly conserved among the variants of concern (VOCs) and variants of interest (VOIs). Taken together, the findings provide a potential material for rapid diagnosis methods of COVID-19.
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Affiliation(s)
- Aiping Wang
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, P.R. China.,Longhu laboratory of advanced immunology, Zhengzhou 450002, P.R. China.,Henan Key Laboratory of Immunobiology, Zhengzhou 450001, P.R. China
| | - Yuanyuan Tian
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, P.R. China.,Longhu laboratory of advanced immunology, Zhengzhou 450002, P.R. China.,Henan Key Laboratory of Immunobiology, Zhengzhou 450001, P.R. China
| | - Hongliang Liu
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, P.R. China.,Longhu laboratory of advanced immunology, Zhengzhou 450002, P.R. China.,Henan Key Laboratory of Immunobiology, Zhengzhou 450001, P.R. China
| | - Peiyang Ding
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, P.R. China.,Longhu laboratory of advanced immunology, Zhengzhou 450002, P.R. China.,Henan Key Laboratory of Immunobiology, Zhengzhou 450001, P.R. China
| | - Yumei Chen
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, P.R. China.,Longhu laboratory of advanced immunology, Zhengzhou 450002, P.R. China.,Henan Key Laboratory of Immunobiology, Zhengzhou 450001, P.R. China
| | - Chao Liang
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, P.R. China.,Longhu laboratory of advanced immunology, Zhengzhou 450002, P.R. China.,Henan Key Laboratory of Immunobiology, Zhengzhou 450001, P.R. China
| | - Yongkun Du
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, P.R. China
| | - Dawei Jiang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, P.R. China
| | - Xifang Zhu
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, P.R. China.,Longhu laboratory of advanced immunology, Zhengzhou 450002, P.R. China.,Henan Key Laboratory of Immunobiology, Zhengzhou 450001, P.R. China
| | - Jiajia Yin
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, P.R. China.,Longhu laboratory of advanced immunology, Zhengzhou 450002, P.R. China.,Henan Key Laboratory of Immunobiology, Zhengzhou 450001, P.R. China
| | - Gaiping Zhang
- School of Life Sciences, Zhengzhou University, Zhengzhou 450001, P.R. China.,Longhu laboratory of advanced immunology, Zhengzhou 450002, P.R. China.,Henan Key Laboratory of Immunobiology, Zhengzhou 450001, P.R. China.,College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, P.R. China
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Identification of a B-Cell Epitope in the VP3 Protein of Senecavirus A. Viruses 2021; 13:v13112300. [PMID: 34835106 PMCID: PMC8621820 DOI: 10.3390/v13112300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/11/2021] [Accepted: 11/16/2021] [Indexed: 12/03/2022] Open
Abstract
Senecavirus A (SVA) is a member of the genus Senecavirus of the family Picornaviridae. SVA-associated vesicular disease (SAVD) outbreaks have been extensively reported since 2014–2015. Characteristic symptoms include vesicular lesions on the snout and feet as well as lameness in adult pigs and even death in piglets. The capsid protein VP3, a structural protein of SVA, is involved in viral replication and genome packaging. Here, we developed and characterized a mouse monoclonal antibody (mAb) 3E9 against VP3. A motif 192GWFSLHKLTK201 was identified as the linear B-cell epitope recognized by mAb 3E9 by using a panel of GFP-tagged epitope polypeptides. Sequence alignments show that 192GWFSLHKLTK201 was highly conserved in all SVA strains. Subsequently, alanine (A)-scanning mutagenesis indicated that W193, F194, L196, and H197 were the critical residues recognized by mAb 3E9. Further investigation with indirect immunofluorescence assay indicated that the VP3 protein was present in the cytoplasm during SVA replication. In addition, the mAb 3E9 specifically immunoprecipitated the VP3 protein from SVA-infected cells. Taken together, our results indicate that mAb 3E9 could be a powerful tool to work on the function of the VP3 protein during virus infection.
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