University of Oxford, Roosevelt Dr, Oxford OX3 7BN, UK; Qatar Foundation (QRLP), Doha, State of Qatar.
University of Oxford, Roosevelt Dr, Oxford OX3 7BN, UK.
J Control Release. 2017 Apr 10;251:92-100. doi: 10.1016/j.jconrel.2017.02.031. Epub 2017 Feb 28.
DNA rich in unmethylated CG motifs (CpGs) engage Toll-Like Receptor 9 (TLR-9) in endosomes and are well described stimulators of the innate and adaptive immune system. CpGs therefore can efficiently improve vaccines' immunogenicity. Packaging CpGs into nanoparticles, in particular into virus-like particles (VLPs), improves the pharmacological characteristics of CpGs as the protein shell protects them from DNAse activity and delivers the oligomers to the endosomal compartments of professional antigen presenting cells (APCs). The current consensus in packaging and delivering CpGs in VLP-based vaccines is that both adjuvants and antigens should be kept in close proximity (i.e. physically linked) to ensure delivery of antigens and adjuvants to the same APCs. In the current study, we harness the draining properties of the lymphatic system and show that also non-linked VLPs are efficiently co-delivered to the same APCs in lymph nodes. Specifically, we have shown that CpGs can be packaged in one VLP and mixed with another VLP displaying the antigen prior to administration in vivo. Both VLPs efficiently reached the same draining lymph node where they were taken up and processed by the same APCs, namely dendritic cells and macrophages. This resulted in induction of specific CTLs producing cytokines and killing target cells in vivo at levels seen when using VLPs containing both CpGs and chemically conjugated antigen. Thus, delivery of antigens and adjuvants in separate nanoparticles eliminates the need of physical conjugation and thus can be beneficial when designing precision medicine VLP-based vaccines or help to re-formulate existing VLP vaccines not naturally carrying immunostimulatory sequences.
富含未甲基化 CG 基序（CpG）的 DNA 与 Toll 样受体 9（TLR-9）结合在内体中，是先天和适应性免疫系统的良好刺激物。因此，CpG 可以有效地提高疫苗的免疫原性。将 CpG 包装成纳米颗粒，特别是病毒样颗粒（VLPs），可以改善 CpG 的药理学特性，因为蛋白质外壳可以保护它们免受 DNA 酶的活性，并将寡聚物递送至专业抗原呈递细胞（APCs）的内体区室。目前在基于 VLP 的疫苗中包装和递送 CpG 的共识是，佐剂和抗原都应保持近距离（即物理连接），以确保将抗原和佐剂递送至相同的 APC。在当前的研究中，我们利用了淋巴系统的引流特性，并表明即使是非连接的 VLPs 也可以有效地递送至淋巴结中的相同 APC。具体而言，我们已经表明，CpG 可以包装在一个 VLP 中，并在体内给药之前与另一个展示抗原的 VLP 混合。两种 VLP 都有效地到达了相同的引流淋巴结，在那里它们被相同的 APC 摄取和处理，即树突状细胞和巨噬细胞。这导致了特异性 CTL 的诱导，这些 CTL 在体内产生细胞因子并杀伤靶细胞，其水平与使用同时包含 CpG 和化学缀合抗原的 VLP 时相同。因此，在单独的纳米颗粒中递送抗原和佐剂消除了物理缀合的需要，因此在设计基于精确医学 VLP 的疫苗或帮助重新配制不自然携带免疫刺激序列的现有 VLP 疫苗时可能是有益的。
