N-glycosylation-mutated HCV envelope glycoprotein complex enhances antigen-presenting activity and cellular and neutralizing antibody responses.
BACKGROUND
The development of an efficient vaccine and broadly cross-neutralizing antibodies of hepatitis C virus (HCV) remains a priority. The heavily glycosylated viral envelope glycoprotein E1E2 complex is a candidate vaccine antigen. Bacteria-derived unmethylated CpG DNA, a potent stimulator of immune cells, is important for vaccine research.


METHODS
Here, the immunogenicities of wild type (WT) E1E2, five N-glycosylation site mutated E1E2 glycoproteins, and five CpG-coupled E1E2 N-glycosylation mutated glycoproteins were analyzed in BALB/c mice by DNA vaccination using in vivo electroporation.


RESULTS
The E1E2 protein expression levels were examined and shown to be unaffected by these N-glycosylation mutations. We found that a CpG-coupled E1-N209D-E2-N430D DNA vaccine (named CpG-E1E2-M4) induced the highest cellular immune response compared to the WT E1E2, CpG-E1E2, and other mutants. Furthermore, the CpG-E1E2-M4 anti-serum effectively neutralized the infection of cell-cultured HCV (HCVcc, genotype 2a)- and HCV pseudo particles (HCVpp, genotypes 1 to 7) to Huh-7.5.1 hepatocytes. Additionally, CpG-E1E2-M4 enhanced the Interleukin-12 (IL-12) production and antigen-presenting activity of CD11c(+) dendritic cells (DCs) by inducing CD4(+) Th1 polarization and the production of perforin and granzyme B (GrB) in CD8(+) T cells.


CONCLUSIONS
As our knowledge this is the first study revealing that the naturally poor immunogenicity of E1E2 can be enhanced by the deletion of N-glycans combined with the addition of immune activator CpG by DNA vaccination.


CONCLUSIONS
Deletion of N-glycans can enhance viral immunogenicity. The selected CpG-E1E2-M4 mutant is a novel potential HCV DNA vaccine that elicits enhanced CD4(+) Th1 and CD8(+) T cell responses and neutralizing antibody production against HCV infection. This article is part of a Special Issue entitled "Glycans in personalised medicine" Guest Editor: Professor Gordan Lauc.
State Key Laboratory of Virology and Department of Immunology and Hubei Province Key Laboratory of Allergy and Immunology, Wuhan University School of Medicine, Donghu Road 185#, Wuhan 430071, Hubei Province, China.
Yushan
Y
Ren
State Key Laboratory of Virology and Department of Immunology and Hubei Province Key Laboratory of Allergy and Immunology, Wuhan University School of Medicine, Donghu Road 185#, Wuhan 430071, Hubei Province, China.
Yuan-Qin
YQ
Min
State Key Laboratory of Virology and Department of Immunology and Hubei Province Key Laboratory of Allergy and Immunology, Wuhan University School of Medicine, Donghu Road 185#, Wuhan 430071, Hubei Province, China.
Min
M
Liu
Center of Glycoscience, Shandong University, Jinan 250100, Shangdong Province, China.
Lianli
L
Chi
Department of Microbiology, Second Military Medical University, Shanghai 200433, China.
Ping
P
Zhao
State Key Laboratory of Virology and Department of Immunology and Hubei Province Key Laboratory of Allergy and Immunology, Wuhan University School of Medicine, Donghu Road 185#, Wuhan 430071, Hubei Province, China. Electronic address: zhangxiaolian@whu.edu.cn.
Xiao-Lian
XL
Zhang
D019943:Amino Acid Substitution; D000818:Animals; D057134:Antibodies, Neutralizing / Q000276:immunology*; D017951:Antigen Presentation; D018414:CD8-Positive T-Lymphocytes; D002460:Cell Line; D018899:CpG Islands; D003713:Dendritic Cells / Q000276:immunology; D005260:Female; D057809:HEK293 Cells; D006367:HeLa Cells; D016174:Hepacivirus / Q000235:genetics / Q000276:immunology*; D006526:Hepatitis C / Q000235:genetics / Q000276:immunology*; D018937:Hepatitis C Antibodies / Q000276:immunology*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D020125:Mutation, Missense; D018417:Th1 Cells / Q000276:immunology; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology* / Q000494:pharmacology; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology*; D014761:Viral Hepatitis Vaccines / Q000235:genetics / Q000276:immunology*
D057134:Antibodies, Neutralizing; D018937:Hepatitis C Antibodies; D019444:Vaccines, DNA; D014759:Viral Envelope Proteins; D014761:Viral Hepatitis Vaccines
Cellular immune response; DNA vaccine; Hepatitis C virus; N-glycosylation; Neutralization