Replacing the decoy epitope of PCV2b capsid protein with a protective epitope enhances efficacy of PCV2b vaccine.
Microbial pathogens may evolve decoy epitopes to evade host immune responses. In recent years, a decoy epitope has been identified in the capsid protein (CP) of porcine circovirus type 2b (PCV2b) to divert the immune response away from protective epitopes in pigs. To avoid the decoy effect, we designed and produced a recombinant PCV2b CP (ΔCP) by replacing the decoy epitope with a neutralizing B cell epitope derived from CP and tested the ability of ΔCP to induce protective antibody responses in mice and pigs. As expected, the ΔCP, unlike inactivated PCV2b vaccines, recombinant PCV2b CP, and natural PCV2b infection, did not induce anti-decoy epitope antibodies. Although unable to form typical virus-like particles (VLPs), the ΔCP could increase the production of the anti-PCV2b antibodies among which no antibody against the decoy epitopes, and therefore induces improved protective immune responses in pigs challenged with PCV2b. These results provide an alternative strategy for development of recombinant subunit vaccines against PCV2b, and possibly other viruses, by replacing the decoy epitope with a protective epitope.
Department of Molecular Biology, College of Basic Medical Sciences, Norman Bethune Health Science Center, Jilin University, Changchun 130021, China; Department of Epidemiology and Biostatistics, School of Public Health, Jilin University, Changchun 130021, China.
Cheng
C
Yu
Department of Molecular Biology, College of Basic Medical Sciences, Norman Bethune Health Science Center, Jilin University, Changchun 130021, China.
Xin
X
Li
Department of Immunology, College of Basic Medical Sciences, Norman Bethune Health Science Center, Jilin University, Changchun 130021, China.
Jiwei
J
Liu
Department of Molecular Biology, College of Basic Medical Sciences, Norman Bethune Health Science Center, Jilin University, Changchun 130021, China.
Wenzhen
W
Diao
Department of Pathology, Third Hospital (China-Japan Union Hospital) of Jilin University, Changchun 130033, China.
Leichao
L
Zhang
Department of Molecular Biology, College of Basic Medical Sciences, Norman Bethune Health Science Center, Jilin University, Changchun 130021, China.
Yue
Y
Xiao
Department of Molecular Biology, College of Basic Medical Sciences, Norman Bethune Health Science Center, Jilin University, Changchun 130021, China.
Hongfei
H
Wei
Department of Immunology, College of Basic Medical Sciences, Norman Bethune Health Science Center, Jilin University, Changchun 130021, China.
Yongli
Y
Yu
Department of Epidemiology and Biostatistics, School of Public Health, Jilin University, Changchun 130021, China. Electronic address: yuyaqin5540@163.com.
Yaqin
Y
Yu
Department of Molecular Biology, College of Basic Medical Sciences, Norman Bethune Health Science Center, Jilin University, Changchun 130021, China. Electronic address: wlying@jlu.edu.cn.
Liying
L
Wang
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D036022:Capsid Proteins / Q000235:genetics / Q000276:immunology*; D018173:Circoviridae Infections / Q000517:prevention & control*; D017925:Circovirus / Q000235:genetics / Q000276:immunology*; D018985:Epitopes, B-Lymphocyte / Q000235:genetics / Q000276:immunology*; D051379:Mice; D013552:Swine; D013553:Swine Diseases / Q000517:prevention & control*; D016896:Treatment Outcome; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology; D014765:Viral Vaccines / Q000235:genetics / Q000276:immunology*
D000914:Antibodies, Viral; D036022:Capsid Proteins; D018985:Epitopes, B-Lymphocyte; D014614:Vaccines, Synthetic; D014765:Viral Vaccines
Capsid protein; Decoy epitope; Porcine circovirus type 2b; Vaccine