Multifunctional calcium phosphate nanoparticles as novel HIV-1 vaccine platform

免疫球蛋白Fc效应器功能对HIV疫苗疗效的重要性日益被认识到。虽然不同类型的疫苗被证明可以诱导具有不同Fc活性的抗体，但如何用所需的Fc效应器功能模式提高HIV-Env抗体应答还没有明确的策略。此前，我们证明了对环境病毒的抗体反应似乎是有偏见的，无论是在人类还是在小鼠身上。而具有Th2移位表型的Env特异性CD4+T细胞是导致小鼠IgG1偏向的原因。基于我们之前的研究结果，我们建议探索两种新的HIV-1疫苗接种策略，这两种策略都基于多功能钙磷纳米颗粒(NPs)。我们的目标是绕过环境诱导的T辅助细胞反应的偏见，并保持环境免疫原的天然三聚体结构，这是提高针对构象表位的抗体所必需的。工作方案包括一种新的双组分疫苗策略，其中第一组分被优化以诱导T辅助细胞反应，而第二组分以正确构象将环境免疫原呈现给B细胞。对于HIV-Env特异性T辅助细胞反应的启动，我们建议将HIV-Env的线性合成肽与Th1T细胞极化的TLR配体一起包裹在CAP纳米颗粒中。CD11c靶向抗体的表面功能化应该会引导这些NPs走向树突状细胞。为了针对B细胞，我们的目标是开发和表征定向包被构象稳定的、可溶的HIV-1包膜尖峰的帽NPs，并在其内部带有TLR配体的官能化。第二种疫苗策略包括招募由普通Th细胞诱导的异种Th细胞，以获得许可，为Env功能化的帽状包裹病毒颗粒提供有效的结构内帮助。特许疫苗中使用的包裹颗粒将受到保护，使其免受抗体反应的影响，但由于内切溶酶体中的酸性pH，在被抗原提呈细胞摄取后，包裹颗粒会迅速解开。这两种不同接种策略的免疫原性将在小鼠模型中确定。

The importance of IgG Fc-effector functions for the efficacy of HIV vaccines is increasingly recognized. Although different types of vaccines were shown to induce antibodies with different Fc-activities, there is no clear strategy how to raise HIV-Env antibody responses with a desired pattern of Fc-effector functions. Previously we demonstrated that the antibody responses to Env appear to be biased, both in humans and in mice. And Env-specific CD4+ T-cells with a Th2-shifted phenotype are responsible for the IgG1 bias in mice. Based on our previous results, we propose to explore two novel HIV-1 vaccination strategies, both based on multifunctional calcium-phosphate (CaP) nanoparticles (NPs). We aim to bypass the Env-induced bias in T-helper cell responses, and maintain the native trimeric structure of the Env immunogen required to raise antibodies to conformational epitopes. The work programme includes a novel two component vaccine strategy, in which first component is optimized for induction of T-helper cell responses, while the second component presents the Env immunogen in the correct conformation to the B-cells. For priming of HIV-Env specific T-helper cell responses, we propose to encapsulate linear synthetic peptides of HIV-Env together with TLR-ligands for Th1 T-cell polarization in CaP nanoparticles. Surface functionalization with CD11c-targeting antibodies should guide these NPs to dendritic cells. To target B-cells we aim to develop and characterize CaP NPs directionally coated with conformationally stabilized, soluble HIV-1 Env-spikes and functionalized with TLR-ligands inside. A second vaccination strategy includes the recruitment of heterologous Th cells induced by a common licensed to provide efficient intrastructural help for Env-functionalized CaP-wrapped virus particles. Wrapped particles used in licensed vaccines will be protected from the antibody responses, but be rapidly unwrapped due to the acidic pH in the endo-lysosome after uptake by antigen-presenting cells. The immunogenicity of the two different vaccination strategies will be determined in mouse models.