Huang Xun, Zhu Qianqian, Huang Xiaoxing, Yang Lifei, Song Yufeng, Zhu Ping, Zhou Paul
Unit of Antiviral Immunity and Genetic Therapy, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China.
Unit of Antiviral Immunity and Genetic Therapy, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China; Shanghai Tech University, Shanghai, China.
Vaccine. 2017 Apr 11;35(16):2042-2051. doi: 10.1016/j.vaccine.2017.03.006. Epub 2017 Mar 17.
Although in vivo electroporation (EP) has been utilized to improve immunogenicity in DNA vaccines alone or in prime-boost regimens with both proteins and viral-vectors, no studies on in vivo EP in DNA-VLP prime-boost regimens against HIV-1 have been reported. Previously we developed stably transfected Drosophila S2 clones to produce HIV-1 virus-like particles (VLP) and demonstrated that priming mice twice with DNA plasmids encoding HIV-1 gp120 and gag and boosting twice with HIV-1 VLP (i.e. DDVV immunization) elicited both envelope-specific antibody and envelope and gag-specific CD8 T cell responses. However, the potency and the breadth of immunogenicity still need to be improved. In this study we tested the effect of in vivo EP during DNA priming on immunogenicity of this DNA-VLP prime-boost regimen. Here we report that although both DDVV and DDVV+EP elicited gp120-specific ELISA-binding antibody responses, average EC values of gp120-specific ELISA-binding total IgG, IgG2a, but not IgG1, antibody responses were significantly higher in DDVV+EP than in DDVV. Moreover, while DDVV elicited neutralizing antibody responses against autologous, but not other five, strains tested, DDVV+EP not only elicited significantly higher anti-autologous neutralizing antibody responses, but also cross-neutralizes four of five other HIV-1 strains tested, including two tier 2 strains. Finally, although CD4 and CD8 T cells from both DDVV and DDVV+EP immunizations secreted IFN-γ, IL-2, TNF-α upon HIV-1 envelope peptide stimulation, average HIV-1 envelope-specific CD8 T cells that secreted IFN-γ, IL-2 and/or TNF-α were significantly higher in DDVV+EP than in DDVV. Thus we conclude that DDVV+EP immunization preferentially increases HIV-1 envelope-specific T1 cytokine-mediated IgG2a responses and significantly enhances the potency and the breadth of neutralizing antibody responses including tier 2 viruses. Further study on this heterologous regimen in large animals is warranted.
尽管体内电穿孔（EP）已被用于单独改善DNA疫苗的免疫原性，或用于蛋白质和病毒载体的初免-加强免疫方案，但尚未有关于DNA-VLP初免-加强免疫方案中针对HIV-1的体内EP研究报道。此前，我们开发了稳定转染的果蝇S2克隆以产生HIV-1病毒样颗粒（VLP），并证明用编码HIV-1 gp120和gag的DNA质粒对小鼠进行两次初免，并用HIV-1 VLP进行两次加强免疫（即DDVV免疫）可引发包膜特异性抗体以及包膜和gag特异性CD8 T细胞反应。然而，免疫原性的效力和广度仍需提高。在本研究中，我们测试了DNA初免期间体内EP对该DNA-VLP初免-加强免疫方案免疫原性的影响。在此我们报告，尽管DDVV和DDVV+EP均引发了gp120特异性ELISA结合抗体反应，但DDVV+EP中gp120特异性ELISA结合总IgG、IgG2a（而非IgG1）抗体反应的平均EC值显著高于DDVV。此外，虽然DDVV引发了针对所测试的自体毒株而非其他五种毒株的中和抗体反应，但DDVV+EP不仅引发了显著更高的抗自体中和抗体反应，还对所测试的其他五种HIV-1毒株中的四种产生交叉中和作用，包括两种2级毒株。最后，尽管来自DDVV和DDVV+EP免疫的CD4和CD8 T细胞在HIV-1包膜肽刺激下均分泌IFN-γ、IL-2、TNF-α，但分泌IFN-γ、IL-2和/或TNF-α的平均HIV-1包膜特异性CD8 T细胞在DDVV+EP中显著高于DDVV。因此，我们得出结论，DDVV+EP免疫优先增加HIV-1包膜特异性T1细胞因子介导的IgG2a反应，并显著增强包括2级病毒在内的中和抗体反应的效力和广度。有必要对这种异源免疫方案在大型动物中进行进一步研究。
