Deletion of N-glycosylation sites of hepatitis C virus envelope protein E1 enhances specific cellular and humoral immune responses.
N-linked glycosylations of viral proteins have been implicated in immunogenicity. In this study, the effects of the N-linked glycosylation of the hepatitis C virus (HCV) E1 protein, a naturally poor immunogen, on the induction of specific immune response were examined. We constructed the plasmids containing the genes encoding both wild type and mutant E1 proteins in which N-linked glycosylation sites are mutated individually or in combination by site-directed mutagenesis. The immunogenicity of wild type E1 and six mutated E1 proteins was analyzed in BALB/C mice using a DNA-based vaccination approach. We found that E1-M2 mutant (at site of N209SS) significantly enhanced E1-specific CD8(+)T cells cytotoxic T lymphocytes (CTL) activities, expression of IFN-gamma producing T cells, and suppression of tumor growth. While E1-M4 mutant (at site of N305CS) induced the highest specific antibody response among all groups. Moreover, E1 wild-type vaccinated mice developed a mixture of IgG1 and Ig2a, but E1-M2 mutant induced only IgG2a isotype, and E1-M4 mutant dominantly developed IgG1 isotype. Our data showed that N-linked glycosylation can limit both cellular and antibody response to the HCV E1 protein and deletion of the N-glycosylation sites at N209SS and N305CS of hepatitis C virus envelope protein E1 provided potential applications for the development of DNA vaccine with enhanced immunogenicity.
Liu
Min
M
Department of Immunology, State Key Laboratory of Virology and Hubei Province Key Laboratory of Allergy and Immunology, Wuhan University School of Medicine, Wuhan 430071, China.
Chen
Haidan
H
Luo
Fengling
F
Li
Pingfei
P
Pan
Qin
Q
Xia
Bing
B
Qi
Zhongtian
Z
Ho
Wen-Zhe
WZ
Zhang
Xiao-Lian
XL
D000595:Amino Acid Sequence; D000818:Animals; D000917:Antibody Formation / Q000235:genetics / Q000276:immunology*; D001665:Binding Sites / Q000235:genetics; D015153:Blotting, Western; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000378:metabolism; D045744:Cell Line, Tumor; D016207:Cytokines / Q000378:metabolism; D005260:Female; D006031:Glycosylation; D016174:Hepacivirus / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D007111:Immunity, Cellular / Q000235:genetics / Q000276:immunology*; D007371:Interferon-gamma / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D011994:Recombinant Proteins / Q000276:immunology / Q000378:metabolism; D017384:Sequence Deletion; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism
D016207:Cytokines; C087035:E1 protein, Hepatitis C virus; D011994:Recombinant Proteins; D019444:Vaccines, DNA; D014759:Viral Envelope Proteins; D007371:Interferon-gamma