title: Identification of three PPV1 VP2 protein-specific B cell linear epitopes using monoclonal antibodies against baculovirus-expressed recombinant VP2 protein.
abstract: Porcine parvovirus type 1 (PPV1) is a major causative agent of embryonic and fetal death in swine. The PPV1 VP2 protein is closely associated with viral immunogenicity for eliciting neutralizing antibodies, but its antigenic structures have been largely unknown. We generated three monoclonal antibodies (MAbs) against baculovirus-expressed recombinant PPV1 VP2 protein. A PEPSCAN analysis identified the minimal B cell linear epitopes of PPV1 VP2 based on these MAbs. Three core epitopes, (228)QQITDA(233), (284)RSLGLPPK(291), and (344)FEYSNGGPFLTPI(356), were defined and mapped onto three-dimensional models of the PPV1 virion and VP2 monomer. The epitope (228)QQITDA(233) is exposed on the virion surface, and the other two are located inside the protein. An alignment of the PPV1 VP2 amino acid sequences showed that (284)RSLGLPPK(291) and (344)FEYSNGGPFLTPI(356) are absolutely conserved, whereas (228)QQITDA(233) has a single substitution at residue 233 in some (S → A or T). We developed a VP2 epitope-based indirect enzyme-linked immunosorbent assay (iELISA) to test for anti-PPV1 antibodies. In a comparative analysis with an immunoperoxidase monolayer assay using 135 guinea pig sera, the VP2-epitope-based iELISA had a concordance rate of 85.19 %, sensitivity of 83.33 %, and specificity of 85.47 %. MAb 8H6 was used to monitor VP2 during the PPV1 replication cycle in vitro with an indirect immunofluorescence assay, which indicated that newly encapsulated virions are released from the nucleus at 24 h postinfection and the PPV1 replication cycle takes less than 24 h. This study provides valuable information clarifying the antigenic structure of PPV1 VP2 and lays the foundations for PPV1 serodiagnosis and antigen detection.
authors.affiliation: Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), 427 Maduan Street, Nangang District, Harbin, 150001, People's Republic of China. sjh2008339@126.com.
authors.forename: Jianhui
authors.initials: J
authors.lastname: Sun
authors.affiliation: Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), 427 Maduan Street, Nangang District, Harbin, 150001, People's Republic of China. hlp@hvri.ac.cn.
authors.forename: Liping
authors.initials: L
authors.lastname: Huang
authors.affiliation: Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), 427 Maduan Street, Nangang District, Harbin, 150001, People's Republic of China. wyw@hvri.ac.cn.
authors.forename: Yanwu
authors.initials: Y
authors.lastname: Wei
authors.affiliation: Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), 427 Maduan Street, Nangang District, Harbin, 150001, People's Republic of China. yipingwang1987@163.com.
authors.forename: Yiping
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), 427 Maduan Street, Nangang District, Harbin, 150001, People's Republic of China. 185400509@qq.com.
authors.forename: Dongjie
authors.initials: D
authors.lastname: Chen
authors.affiliation: Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), 427 Maduan Street, Nangang District, Harbin, 150001, People's Republic of China. 1083299525@qq.com.
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Du
authors.affiliation: Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), 427 Maduan Street, Nangang District, Harbin, 150001, People's Republic of China. hlw2009happy@163.com.
authors.forename: Hongli
authors.initials: H
authors.lastname: Wu
authors.affiliation: Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), 427 Maduan Street, Nangang District, Harbin, 150001, People's Republic of China. fengli@caas.cn.
authors.forename: Li
authors.initials: L
authors.lastname: Feng
authors.affiliation: Division of Swine Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), 427 Maduan Street, Nangang District, Harbin, 150001, People's Republic of China. lcm@hvri.ac.cn.
authors.forename: Changming
authors.initials: C
authors.lastname: Liu
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000914:Antibodies, Viral / Q000276:immunology*; D000956:Antigens, Viral / Q000235:genetics / Q000276:immunology*; D016367:Baculoviridae; D036022:Capsid Proteins / Q000235:genetics / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D018985:Epitopes, B-Lymphocyte / Q000276:immunology*; D005822:Genetic Vectors; D006168:Guinea Pigs; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D013552:Swine
chemical_list: D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D000956:Antigens, Viral; D036022:Capsid Proteins; D018985:Epitopes, B-Lymphocyte; D011994:Recombinant Proteins; C528774:VP2 protein, porcine parvovirus
keywords: Core epitope; MAb; Porcine parvovirus type 1; Serodiagnosis; VP2 protein