超声介导促抗原交叉递呈的新型肿瘤纳米疫苗构建及其在乳腺癌治疗中的应用

Peptide vaccine for tumor is promising for the treatment of breast cancer. Nanovaccine composed of antigen and nanoparticles, serving as antigen protectors and carriers, can boost the antitumor immune response by enhancing lysosome escape to improve antigen cross-presentation. However, the applications of nanovaccine in clinic were limited for the side effect and bad biosafety of carrier. It has been reported that ultrasound could trigger the release of gas to increase lysosome escape for further delivering nanodrug in a safe and effective way. Besides, the gas as an ultrasound contrast agent can be applied in the design of tumor nanovaccine. Based on the reasonable analysis and preliminary work of the design of self-assembly of antigen protein, a novel nanovaccine loading oxygen was developed via intermolecular disulfide by HSA nanoparticles hybrid with hemoglobin to load adjuvant R837 and oxygen. The oxygen loading nanovaccine was endowed with good stability, biocompatibility, ultrasound sensitivity and Contrast-enhanced ultrasound (CEUS) and could target lymphatic more efficiently. The oxygen was released from the nanovaccine inside the lysosome under ultrasound after the nanovaccine was captured by DCs, which could induce antigen cross-presentation and further tumor specific killing. The oxygen bubble released from nanovaccine could enhance the effect of CEUS with the function of monitoring and visualizing the migration and lymphatic retention of nanovaccine dynamically. The research is expected to develop a novel strategy for the design of tumor nanovaccine and improving the therapy of breast cancer.

多肽疫苗的发展为乳腺癌的治疗带来了新的希望。纳米载体保护多肽抗原免于酶解，并通过溶酶体逃逸，高效提升抗原交叉递呈水平以增效乳腺癌免疫治疗。但纳米疫苗促溶酶体逃逸存在载体副作用大、生物风险高等缺陷，阻碍了进一步的临床应用。研究发现，超声可调控气体释放，安全高效地促进药物溶酶体逃逸，兼具造影功能，可改善纳米疫苗的弊端。据此，本项目拟结合血清蛋白HSA的淋巴靶向优势，在蛋白自组装纳米疫苗的前期基础上，通过调控HSA上的巯基进行自组装，与载氧的血红蛋白杂交，负载抗原肽与佐剂，构建一种生物安全性高、二硫键交联稳定、可淋巴靶向、兼具超声响应与造影功能的载氧纳米疫苗。借助超声技术，可调控氧气在树突细胞溶酶体中释放，实现促抗原交叉提呈进而杀伤肿瘤的目标；同时，释放的氧气增强了超声造影，可进行疫苗迁移与淋巴富集的动态监测与可视化研究。该研究有望为肿瘤纳米疫苗的设计及乳腺癌的免疫治疗提供新的方法和理论依据。

纳米颗粒可通过促进疫苗组分溶酶体逃逸，提升抗原交叉递呈，进而提升肿瘤免疫治疗效果。但目前纳米疫苗普遍存在载体副作用大、生物风险高、免疫系统靶向差、抗原递呈效率低差等缺陷，阻碍了临床应用。光、声、磁等外部刺激可调节疫苗与免疫系统的相互作用，这为肿瘤纳米疫苗的设计带来了新的思路。为此，申请人在已有的淋巴靶向白蛋白纳米载体设计合成基础上，结合光刺激、超声刺激等手段，设计出新型环境响应型肿瘤纳米疫苗。.1）光响应纳米疫苗：申请人利用血清白蛋白偶联抗原肽作为载体，负载光敏剂吲哚菁绿ICG，而后通过组装负载佐剂咪喹莫特R837，成功制备出光响应纳米疫苗。该疫苗合成手段简单、可批次化生产。在红外光辐照条件下，该纳米疫苗可高效促进树突细胞的成熟，在小鼠引流淋巴结内诱导产生了高达5.1%肿瘤特异性杀T细胞。数据显示：纳米疫苗在小鼠宫颈癌TC-1模型上获得良好的免疫预防与治疗效果。2) 超声响应纳米疫苗：申请人进一步利用白蛋白自纳米化技术，通过巯基/二硫键反应，负载上可携氧的血红蛋白、抗原肽及佐剂，制备超声刺激响应的纳米疫苗。该纳米疫苗在超声作用下，有效促进了的抗原的交叉递呈，诱导产生了大量的的肿瘤杀伤性T细胞。超声辐照+纳米疫苗组相比未超声辐照组在小鼠体内刺激诱导产生了高达4倍多的肿瘤抗原特异性杀伤T细胞，表现出巨大的临床应用潜力。.本项目的科学意义在于证实了超声、光等外界刺激因素可调控纳米疫苗的抗原递呈效率，进而诱导小鼠产生高水平的抗肿瘤特异性杀伤T细胞。结合外部刺激响应来调控肿瘤疫苗的抗肿瘤免疫应答是一条行之有效的思路。