A Cobalt Porphyrin Nanoliposome Adjuvant for MHC-I-Restricted Cancer Peptide Vaccines

项目总结 MHC-I类(MHC-I)限制性多肽癌症疫苗含有最少量的生化信息 产生抗原特异性T细胞以引发抗肿瘤反应所必需的。就他们自己而言，通过免疫接种 最小的多肽表位不能提供令人满意的反应，因此通常是长肽或结合多肽 交付系统是必要的。然而，这种方法破坏了短合成肽的直接性。 疫苗。将引入一种新的多肽疫苗免疫范例，基于组合(通过SIMPLE 将MHC-I多肽表位与疫苗佐剂混合，可诱导自发的纳米脂质体抗原 粒子化(SNAP)。快速含有少量钴卟啉-磷脂(CoPoP)的脂质体 通过自发地将组氨酸标签插入到双层中，结合短的组氨酸标记肽(8-9mer)。这就产生了 到在生物介质中稳定的颗粒化。His标记的多肽与CoPoP脂质体简单混合 在接种疫苗时(不需要进一步纯化)将这些特征良好的多肽转化为100 nm 粒子。这种方法在产生抗原特异性CD8+T细胞方面非常有效。AH1是MHC-I H-2LD 模型CD8+表位来源于gp70小鼠白血病病毒抗原。可以使用AH1衍生的多肽 用SNAP免疫产生大量的抗原特异性CD8+T细胞。Snap免疫接种 低纳克剂量的多肽完全保护小鼠免受随后的肿瘤攻击，并100%根除 在治疗性疫苗模型中发现肺转移。将评估SNAP免疫的不同组成部分， 包括His-Tag的长度、共掺的密度和剂量(Mpla和QS-21；都是GSK的一部分 疫苗佐剂AS01)，以确定它们对抗原特异性CD8+反应的影响。银离子专一性的产生 将对CD44+CD62L+细胞进行评估，以确定这种中央记忆细胞在 根除肿瘤。疫苗的有效性将在多种预防和治疗局部和转移中进行测试 肿瘤模型。大型肿瘤的治疗将根据环磷酰胺和 检查站封锁。将通过评估递送的多肽如何到达MHC来探索机械洞察- 一、假设His-Tag多肽与CoPoP脂质体结合，并经历血清稳定的转运到排出 淋巴结。在那里，它们被树突状细胞吞噬，吞噬小体的还原环境 也被怀疑能诱导CoPoP脂质体释放多肽。双层膜上的Toll样受体 被认为是为了上调吞噬小体中MHC-I的表达。进一步的研究将评估 SNAP免疫和抗原复合作为多肽微库体内筛选工具的可行性 使用已建立的肿瘤相关抗原和将被下一代识别的新抗原 测序。最后，将对该系统的安全性和钴响应进行评估。这些研究将提供 用于癌症治疗和治疗的MHC-I限制性短肽癌症疫苗的实质性进展 免疫原性表位筛选。

PROJECT SUMMARY MHC class I (MHC-I) -restricted peptide cancer vaccines hold the minimal amount of biochemical information required for generating antigen-specific T cells to elicit anti-tumor responses. On their own, immunization with minimal peptide epitopes does not provide a satisfactory response, so typically long peptides or conjugated delivery systems are necessitated. However, such approaches defeat the directness of short synthetic peptide vaccines. A new peptide vaccine immunization paradigm will be introduced, based on combining (via simple mixing) MHC-I peptide epitopes with a vaccine adjuvant that induces spontaneous nanoliposome-antigen particleization (SNAP). Liposomes that contain small amounts of cobalt porphyrin-phospholipid (CoPoP) rapidly bind short his-tagged peptides (8-9mers) via spontaneous insertion of the his-tag into the bilayer. This gives rise to particleization that is stable in biological media. His-tagged peptides are simply mixed with CoPoP liposomes at the time of vaccination (without further purification) to convert these well-characterized peptides into a 100 nm particle. This approach is potently effective in generating antigen-specific CD8+ T cells. AH1 is a MHC-I H-2Ld model CD8+ epitope derived from the gp70 murine leukemia virus antigen. An AH1-derived peptide can be used with SNAP immunization to generate high numbers of antigen specific CD8+ T cells. SNAP immunization with low nanogram doses peptides completely protects mice from subsequent tumor challenge, and eradicates 100% of lung metastases in a therapeutic vaccine model. Varying components of SNAP immunization will be assessed, including the his-tag length, the density and dose of co-incorporated (MPLA and QS-21; both part of GSK’s vaccine adjuvant AS01) to determine their impact the Ag-specific CD8+ response. Generation of Ag-specific CD44+ CD62L+ cells will be assessed to determine whether such central memory cells are more effective in eradicating tumors. Vaccine efficacy will be tested in multiple prophylactic and therapeutic local and metastasis tumor models. Therapeutic treatment of large tumors will be assessed with the impact of cyclophosphamide and checkpoint blockade. Mechanistic insights will be probed by assessing how the delivered peptide reaches MHC- I. It is hypothesized that his-tag peptides bind to CoPoP liposomes, and undergo serum-stable transit to draining lymph nodes. There, they are phagocytosed by dendritic cells where the reductive environment of phagosomes is also suspected to induce the release of the peptide from the CoPoP liposomes. Toll-like receptor in the bilayer are hypothesized to upregulate the expression of MHC-I within the phagosome. Further studies will assess the viability of SNAP immunization and antigen multiplexing as an in vivo screening tool for peptide microlibraries using established tumor-associated antigens and neoantigens that will be identified with next-generation sequencing. Finally, the safety and cobalt response of the system will be assessed. These studies will provide substantial advancement for short, MHC-I-restricted peptide-based cancer vaccines for cancer therapy and immunogenic epitope screening.