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.
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.
Min
M
Liu
Haidan
H
Chen
Fengling
F
Luo
Pingfei
P
Li
Qin
Q
Pan
Bing
B
Xia
Zhongtian
Z
Qi
Wen-Zhe
WZ
Ho
Xiao-Lian
XL
Zhang
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