树突状细胞靶向使用 DNA 疫苗诱导针对登革病毒包膜蛋白结构域 III 的特异性抗体和 CD4 T 细胞。
Dendritic Cell Targeting Using a DNA Vaccine Induces Specific Antibodies and CD4 T Cells to the Dengue Virus Envelope Protein Domain III.
机构信息
Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
出版信息
Front Immunol. 2019 Jan 29;10:59. doi: 10.3389/fimmu.2019.00059. eCollection 2019.
Dengue fever has become a global threat, causing millions of infections every year. An effective vaccine against all four serotypes of dengue virus (DENV) has not been developed yet. Among the different vaccination strategies available today, DNA vaccines are safe and practical, but currently induce relatively weak immune responses in humans. In order to improve immunogenicity, antigens may be targeted to dendritic cells (DCs), the main antigen presenting cells and orchestrators of the adaptive immune response, inducing T and B cell activation. It was previously shown that a DNA vaccine encoding a fusion protein comprised of an antigen and a single-chain Fv antibody (scFv) specific for the DC endocytic receptor DEC205 induced strong immune responses to the targeted antigen. In this work, we evaluate this strategy to improve the immunogenicity of dengue virus (DENV) proteins. Plasmids encoding the scFv αDEC205, or an isotype control (scFv ISO), fused to the DENV2 envelope protein domain III (EDIII) were generated, and EDIII specific immune responses were evaluated in immunized mice. BALB/c mice were intramuscularly (i.m.) immunized three times with plasmid DNAs encoding either scDEC-EDIII or scISO-EDIII followed by electroporation. Analyses of the antibody responses indicated that EDIII fusion with scFv targeting the DEC205 receptor significantly enhanced serum anti-EDIII IgG titers that inhibited DENV2 infection. Similarly, mice immunized with the scDEC-EDIII plasmid developed a robust CD4 T cell response to the targeted antigen, allowing the identification of two linear epitopes recognized by the BALB/c haplotype. Taken together, these results indicate that targeting DENV2 EDIII protein to DCs using a DNA vaccine encoding the scFv αDEC205 improves both antibody and CD4 T cell responses. This strategy opens perspectives for the use of DNA vaccines that encode antigens targeted to DCs as a strategy to increase immunogenicity.
登革热已成为全球威胁,每年导致数百万人感染。目前尚未开发出针对所有四种登革热病毒(DENV)血清型的有效疫苗。在当今可用的各种疫苗接种策略中,DNA 疫苗安全且实用,但目前在人类中诱导的免疫应答相对较弱。为了提高免疫原性,抗原可以靶向树突状细胞(DC),DC 是主要的抗原呈递细胞和适应性免疫反应的协调者,可诱导 T 和 B 细胞的激活。先前的研究表明,编码融合蛋白的 DNA 疫苗,该融合蛋白由抗原和针对 DC 内吞受体 DEC205 的单链 Fv 抗体(scFv)组成,可诱导针对靶向抗原的强烈免疫应答。在这项工作中,我们评估了这种策略来提高登革热病毒(DENV)蛋白的免疫原性。生成了编码 scFv αDEC205 或同型对照(scFv ISO)的质粒,与 DENV2 包膜蛋白结构域 III(EDIII)融合,并在免疫接种的小鼠中评估了 EDIII 特异性免疫应答。BALB/c 小鼠经肌肉内(i.m.)免疫三次,用编码 scDEC-EDIII 或 scISO-EDIII 的质粒 DNA 进行电穿孔。抗体反应分析表明,EDIII 与靶向 DEC205 受体的 scFv 融合显著增强了抑制 DENV2 感染的血清抗 EDIII IgG 滴度。同样,用 scDEC-EDIII 质粒免疫的小鼠对靶向抗原产生了强大的 CD4 T 细胞应答,从而鉴定出两个由 BALB/c 单倍型识别的线性表位。综上所述,这些结果表明,使用编码 scFv αDEC205 的 DNA 疫苗将 DENV2 EDIII 蛋白靶向 DC 可改善抗体和 CD4 T 细胞应答。该策略为使用编码靶向 DC 的抗原的 DNA 疫苗作为提高免疫原性的策略开辟了前景。