Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Australia.
Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Australia.
Eur J Pharm Biopharm. 2022 Mar;172:240-252. doi: 10.1016/j.ejpb.2021.09.004. Epub 2021 Sep 24.
Vaccines are a powerful health intervention but there is still an unmet need for effective preventative and therapeutic vaccines for many diseases such as cancer and infections. Interstitial (e.g. subcutaneous (SC)) injection in nano-sized carriers such as high density lipoproteins (HDLs) can improve the access of vaccine subunit antigens or adjuvants to target immune cells in the lymphatics and potentiate vaccination responses such as cytotoxic T lymphocyte (CTL) responses (Kuai et al., 2016, 2018; Qian et al., 2016). Here we examined how cholesterol conjugation to the vaccine adjuvant CpG, and incorporation into HDL, changes lymphatic absorption and association with, and processing by, dendritic cells (DCs), ultimately influencing adjuvant efficacy. We investigated the lymphatic disposition of cholesterol conjugated CpG incorporated into HDL (HDL(Chol-CpG-Cy5)) relative to free cholesterol conjugated CpG (Chol-CpG-Cy5) and unconjugated CpG (free CpG-Cy5) after SC administration in rats and mice. HDL (Chol-CpG-Cy5) and Chol-CpG-Cy5 differentially altered CpG absorption into lymph vs. blood, but surprisingly resulted in similarly higher LN accumulation relative to free CpG. The mechanism of access of Chol-CpG-Cy5 into lymph might be partly due to association with endogenous HDL at the injection site followed by transport into lymph in association with the HDL. To measure CpG association with and processing by DCs and the strength of the immune response, mice were vaccinated with free ovalbumin (OVA) co-administered with the different CpG constructs. There were significant changes in DC activation that were reflective of the trend in LN accumulation at 24 h post-vaccination. However, T cell responses at 24 h and 7 days post-vaccination were not significantly different across the CpG groups although the response was less variable for Chol-CpG-Cy5 compared to free CpG Cy5 and also HDL(Chol-CpG-Cy5) - despite similar LN accumulation with the latter. Overall, our data indicate that cholesterol conjugation and incorporation into HDL increases adjuvant lymph disposition and DC activation.
疫苗是一种强大的健康干预手段，但对于许多疾病（如癌症和感染），仍然需要有效的预防性和治疗性疫苗。将疫苗亚单位抗原或佐剂以纳米大小的载体（如高密度脂蛋白（HDL））进行间质（例如皮下（SC））注射，可以改善疫苗亚单位抗原或佐剂进入淋巴系统中靶免疫细胞的途径，并增强疫苗接种反应，如细胞毒性 T 淋巴细胞（CTL）反应（Kuai 等人，2016 年，2018 年； Qian 等人，2016 年）。在这里，我们研究了胆固醇与疫苗佐剂 CpG 的缀合，并将其掺入 HDL 中，如何改变淋巴吸收以及与树突状细胞（DC）的关联和处理，最终影响佐剂的功效。我们研究了胆固醇缀合 CpG 掺入 HDL（HDL（Chol-CpG-Cy5））相对于游离胆固醇缀合 CpG（Chol-CpG-Cy5）和未缀合 CpG（游离 CpG-Cy5）在大鼠和小鼠 SC 给药后的淋巴分布。HDL（Chol-CpG-Cy5）和 Chol-CpG-Cy5 可改变 CpG 从淋巴吸收到血液的吸收，但令人惊讶的是，与游离 CpG 相比，它们导致淋巴结的积累更高。Chol-CpG-Cy5 进入淋巴的途径的机制部分可能是由于在注射部位与内源性 HDL 结合，然后与 HDL 一起运输到淋巴中。为了测量 Chol-CpG-Cy5 与 DC 的关联和处理以及免疫反应的强度，用不同的 CpG 构建体与游离卵清蛋白（OVA）一起对小鼠进行疫苗接种。在疫苗接种后 24 小时，DC 激活发生了显著变化，这反映了淋巴结积聚的趋势。然而，24 小时和 7 天后的 T 细胞反应在 CpG 组之间没有显著差异，尽管 Chol-CpG-Cy5 与游离 CpG Cy5 相比，反应的变异性更小，并且与 HDL（Chol-CpG-Cy5）相比，尽管后者与淋巴结积累相似。总的来说，我们的数据表明胆固醇缀合和掺入 HDL 可增加佐剂的淋巴分布和 DC 激活。
