The ability of Hepatitis B surface antigen DNA vaccine to elicit cell-mediated immune responses, but not antibody responses, was affected by the deglysosylation of S antigen

Department of Infectious Diseases, Nanjing Medical University, and China-US Vaccine Research Center, Jiangsu Province Hospital, Nanjing 210029, China.
Vaccine (Impact Factor: 3.62). 05/2008; 26(40):5145-52. DOI: 10.1016/j.vaccine.2008.03.072
Source: PubMed


Hepatitis B Virus (HBV) infection remains a major worldwide infectious disease with serious long-term morbidity and mortality. The limited selections of drug treatment are not able to control the progress of disease in people with active and persistent HBV infection. Immunotherapy to control the degree of viral infection is one possible alternative solution to this challenge. HBV DNA vaccines, with their strong ability to induce cell-mediated immune responses, offer an attractive option. HBV surface protein is important in viral immunity. Re-establishing anti-S immunity in chronic HBV infected patients will bring significant benefit to the patients. Previous studies have shown that HBV S DNA vaccines are immunogenic in a number of animal studies. In the current study, we further investigated the effect of glycosylation to the expression and immunogenicity of S DNA vaccines. Our results demonstrate that deglycosylation at the two potential N-linked glycosylation sites in S protein resulted in a significant decrease of S-specific cell-mediated immune responses, but did not affect anti-S antibody responses. This finding provides important direction to the development of S DNA vaccines to elicit the optimal and balanced antibody and cell-mediated immune responses to treat people with HBV chronic infections.

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    • "MHBs possesses two N-linked glycosylation sites: Asn4 in the pre-S2 domain and Asn146 in the S domain. A previous analysis showed that deglycosylation at N-linked glycosylation site (Asn146) in the S domain resulted in a significant decrease in HBs-specific cell-mediated immune responses (Xing et al. 2008), and there is evidence that N-linked glycosylation (Asn4) in the pre-S2 domain plays an essential role in the secretion of MHBs and formation of HBV particles (Block et al. 1994). "
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    ABSTRACT: Infection with hepatitis B virus (HBV) remains a worldwide health problem, and DNA-based vaccines against HBV have been tested for therapeutic applications. HBV possesses three envelope lipoproteins that are translated from a single reading-frame: large, middle, and small HBV surface antigens. Among these envelope proteins, the middle HBV surface antigen (MHBs) contains a constitutive N-linked glycosylation site at position 4 (Asn4) in the amino-terminal portion (MQWNSTTFHQ) of pre-S2 domain. Asn4 (shown in bold) is essential for secretion of viral particles and conserved among all serotypes of HBV, but its influence on the immunogenicity of MHBs remains unknown. Here, we constructed four MHBs genes carrying mutations, underlined, in the amino-terminal portion of pre-S2 domain. One mutant protein contains Q at position 4 (MQWQSTTFHQ). In addition, each of three mutant MHBs proteins contains a N-linked glycosylation site (N-X-S/T), relocated to position 5 (MQWQNTTFHQ), 6 (MQWQSNTSHQ) or 7 (MQWQSTNFTQ) in pre-S2 domain. The expression and immunogenic properties of mutant DNA vaccines were examined in 293T human renal epithelial cells and in BALB/c mice, respectively. We showed that Asn4 was critical for secretion and immunogenicity of MHBs. Moreover, the MHBs protein that carries a N-linked glycosylation site at position 5 or 7 retained the properties similar to wild-type MHBs. In contrast, the secretion-defective mutant protein carrying Asn at position 6 induced only marginal humoral and cellular immune responses in mice, despite the N-linked glycosylation. In conclusion, N-linked glycosylation at an appropriate position in pre-S2 domain is an essential requirement for DNA vaccine expressing MHBs.
    The Tohoku Journal of Experimental Medicine 07/2015; 236(2):131-8. DOI:10.1620/tjem.236.131 · 1.35 Impact Factor
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    • "Gamma interferon (IFN-γ) and interleukin 4 (IL-4) ELISPOT assays were performed to detect the HBs peptide-specific T cell responses in mouse splenocytes, as previously described [27], [35]. Mouse IFN-γ kit (U-CyTech Biosciences, Netherlands) and IL-4 ELISPOT kit (U-CyTech Biosciences, Netherlands) were used to detect HBs-specific IFN-γ and IL-4 T cell responses, according to manufacturers' directions. "
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    ABSTRACT: Although the use of recombinant hepatitis B virus surface (HBsAg) protein vaccine has successfully reduced global hepatitis B infection, there are still a number of vaccine recipients who do not develop detectable antibody responses. Various novel vaccination approaches, including DNA vaccines, have been used to further improve the coverage of vaccine protection. Our previous studies demonstrated that HBsAg-based DNA vaccines could induce both humoral and CMI responses in experimental animal models. However, one form of the the HBsAg antigen, the large S antigen (HBs-L), expressed by DNA vaccine, was not sufficiently immunogenic in eliciting antibody responses. In the current study, we produced a modified large S antigen DNA vaccine, HBs-L(T), which has a truncated N-terminal sequence in the pre-S1 region. Compared to the original HBs-L DNA vaccine, the HBs-L(T) DNA vaccine improved secretion in cultured mammalian cells and generated significantly enhanced HBsAg-specific antibody and B cell responses. Furthermore, this improved HBsL DNA vaccine, along with other HBsAg-expressing DNA vaccines, was able to maintain predominantly Th1 type antibody responses while recombinant HBsAg protein vaccines produced in either yeast or CHO cells elicited mostly Th2 type antibody responses. Our data indicate that HBsAg DNA vaccines with improved immunogenicity offer a useful alternative choice to recombinant protein-based HBV vaccines, particularly for therapeutic purposes against chronic hepatitis infection where immune tolerance led to poor antibody responses to S antigens.
    PLoS ONE 07/2012; 7(7):e41573. DOI:10.1371/journal.pone.0041573 · 3.23 Impact Factor
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    • "Additional studies were conducted to ask if glycosylation of HA has been affected with the use of a different leader sequence which may influence the immune responses. Our previous study with a hepatitis B surface antigen suggested that post-translational modifications including glycosylation may affect the immunogenicity of DNA vaccine delivered antigens [23]. The Asn (N)-linked glycosylation of influenza HA proteins are essential for virus infectivity and vaccine immunogenicity [24], [25]. "
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    ABSTRACT: Highly pathogenic avian influenza A (HPAI) H5N1 viruses are circulating among poultry populations in parts of Asia, Africa, and the Middle East, and have caused human infections with a high mortality rate. H5 subtype hemagglutinin (HA) has evolved into phylogenetically distinct clades and subclades based on viruses isolated from various avian species. Since 1997, humans have been infected by HPAI H5N1 viruses from several clades. It is, therefore, important to develop strategies to produce protective antibody responses against H5N1 viruses from multiple clades or antigenic groups. In the current study, we optimized the signal peptide design of DNA vaccines expressing HA antigens from H5N1 viruses. Cross reactivity analysis using sera from immunized rabbits showed that antibody responses elicited by a polyvalent formulation, including HA antigens from different clades, was able to elicit broad protective antibody responses against multiple key representative H5N1 viruses across different clades. Data presented in this report support the development of a polyvalent DNA vaccine strategy against the threat of a potential H5N1 influenza pandemic.
    PLoS ONE 12/2011; 6(12):e28757. DOI:10.1371/journal.pone.0028757 · 3.23 Impact Factor
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