Pitoiset Fabien, Vazquez Thomas, Levacher Beatrice, Nehar-Belaid Djamel, Dérian Nicolas, Vigneron James, Klatzmann David, Bellier Bertrand
Sorbonne Universités, UPMC Univ Paris 06, Paris, France.
INSERM, UMR_S 959, Immunology-Immunopathology-Immunotherapy (I3), Paris, France.
J Virol. 2017 Oct 13;91(21). doi: 10.1128/JVI.01230-17. Print 2017 Nov 1.
Retrovirus-derived virus-like particles (VLPs) are particularly interesting vaccine platforms, as they trigger efficient humoral and cellular immune responses and can be used to display heterologous antigens. In this study, we characterized the intrinsic immunogenicity of VLPs and investigated their possible adjuvantization by incorporation of Toll-like receptor (TLR) ligands. We designed a noncoding single-stranded RNA (ncRNA) that could be encapsidated by VLPs and induce TLR7/8 signaling. We found that VLPs efficiently induce dendritic cell activation, which can be improved by ncRNA encapsidation (VLPs). Transcriptome studies of dendritic cells harvested from the spleens of immunized mice identified antigen presentation and immune activation as the main gene expression signatures induced by VLPs, while TLR signaling and Th1 signatures characterize VLPs. and compared with standard VLPs, VLPs promoted Th1 responses and improved CD8 T cell proliferation in a MyD88-dependent manner. In an HIV vaccine mouse model, HIV-pseudotyped VLPs elicited stronger antigen-specific cellular and humoral responses than VLPs. Altogether, our findings provide molecular evidence for a strong vaccine potential of retrovirus-derived VLPs that can be further improved by harnessing TLR-mediated immune activation. We previously reported that DNA vaccines encoding antigens displayed in/on retroviral VLPs are more efficient than standard DNA vaccines at inducing cellular and humoral immune responses. We aimed to decipher the mechanisms and investigated the VLPs' immunogenicity independently of DNA vaccination. We show that VLPs have the ability to activate antigen-presenting cells directly, thus confirming their intrinsic immunostimulatory properties and their potential to be used as an antigenic platform. Notably, this immunogenicity can be further improved and/or oriented by the incorporation into VLPs of ncRNA, which provides further TLR-mediated activation and Th1-type CD4 and CD8 T cell response orientation. Our results highlight the versatility of retrovirus-derived VLP design and the value of using ncRNA as an intrinsic vaccine adjuvant.
逆转录病毒衍生的病毒样颗粒(VLPs)是特别有趣的疫苗平台,因为它们能引发有效的体液免疫和细胞免疫反应,并且可用于展示异源抗原。在本研究中,我们表征了VLPs的内在免疫原性,并通过掺入Toll样受体(TLR)配体来研究其可能的佐剂化作用。我们设计了一种可被VLPs包裹并诱导TLR7/8信号传导的非编码单链RNA(ncRNA)。我们发现VLPs能有效诱导树突状细胞活化,而通过ncRNA包裹(VLPs)可使其得到改善。对从免疫小鼠脾脏中收获的树突状细胞进行的转录组研究确定,抗原呈递和免疫激活是由VLPs诱导的主要基因表达特征,而TLR信号传导和Th1特征则是VLPs的特征。与标准VLPs相比,VLPs以MyD88依赖的方式促进Th1反应并改善CD8 T细胞增殖。在HIV疫苗小鼠模型中, HIV假型化的VLPs比VLPs引发更强的抗原特异性细胞和体液反应。总之,我们的研究结果为逆转录病毒衍生的VLPs具有强大的疫苗潜力提供了分子证据,通过利用TLR介导的免疫激活可进一步提高其潜力。我们之前报道过,编码展示于逆转录病毒VLPs内/上的抗原的DNA疫苗在诱导细胞免疫和体液免疫反应方面比标准DNA疫苗更有效。我们旨在破解其中的机制,并独立于DNA疫苗接种来研究VLPs的免疫原性。我们表明VLPs具有直接激活抗原呈递细胞的能力,从而证实了它们固有的免疫刺激特性以及用作抗原平台的潜力。值得注意的是,通过将ncRNA掺入VLPs,这种免疫原性可以进一步改善和/或定向,ncRNA可提供进一步的TLR介导的激活以及Th1型CD4和CD8 T细胞反应定向。我们的结果突出了逆转录病毒衍生的VLP设计的多功能性以及使用ncRNA作为内在疫苗佐剂的价值。