Luna Ernesto, Ruiz Sophie, Garinot Marie, Chavagnac Cyril, Agrawal Pankaj, Escobar John, Revet Laurent, Asensio Marie-Jeanne, Piras Fabienne, Fang Francis G, Drake Donald R, Rokbi Bachra, Larocque Daniel, Haensler Jean
Sanofi Vaccines business unit, R&D, Orlando, FL, USA.
Sanofi Vaccines business unit, R&D, Marcy L'Etoile, France.
NPJ Vaccines. 2024 Dec 19;9(1):253. doi: 10.1038/s41541-024-01046-0.
In the aim of designing and developing a novel saponin-based adjuvant system, we combined the QS21 saponin with low microgram amounts of the fully synthetic TLR4 agonist, E6020, in cholesterol-containing liposomes. The resulting adjuvant system, termed SPA14, appeared as a long-term stable and homogeneous suspension of mostly unilamellar and a few multilamellar vesicles, with an average hydrodynamic diameter of 93 nm, when formulated in citrate buffer at pH 6.0-6.5. When compared in an in vitro human innate immunity construct to AS01B, the QS21/MPL® liposomal adjuvant system of GSK, and with QS21-Liposomes used as benchmarks, SPA14 displayed the strongest immunostimulatory potential based on antigen-presenting cell (APC) activation and cytokine secretion, which was essentially driven by the highly active E6020 agonist in this assay. When tested as an adjuvant in vivo with human cytomegalovirus glycoprotein B (gB) and pentamer complex (PC) as test antigens, SPA14 was generally well tolerated and as active as AS01B for the induction of long-lasting CMV-neutralizing antibodies in mice and non-human primates (NHPs). Both adjuvants promoted the induction of Th-1 responses based on IgG2c production in mice and IFN-γ production in mice and NHPs, but in mice, a higher level of Th-2 cytokines (IL-5) and higher IgG1 over IgG2c secreting cells ratios were obtained with SPA14 indicating that the adjuvant profile of SPA14 could be less Th-1 biased than that of AS01B. From a developability standpoint, SPA14 could be manufactured by a simple and scalable ethanol injection method, owing to the high solubility in ethanol of all its lipidic components, including E6020. Furthermore, E6020 is a single molecule, well-characterized fully synthetic TLR4 agonist constructed in eight synthetic steps from entirely crystalline starting materials and intermediates via an optimized high-yield synthetic route. Overall, our data suggest that SPA14 is a viable, easy-to-manufacture, potent novel adjuvant system that could be broadly applicable as a ready-to-mix adjuvant in the form of a long-term stable liquid formulation.
为了设计和开发一种新型的基于皂苷的佐剂系统，我们将QS21皂苷与微克级的全合成TLR4激动剂E6020，在含胆固醇的脂质体中混合。所得的佐剂系统称为SPA14，当在pH 6.0 - 6.5的柠檬酸盐缓冲液中配制时，它表现为大多是单层和少数多层囊泡的长期稳定且均匀的悬浮液，平均流体动力学直径为93纳米。当在体外人类固有免疫构建体中与葛兰素史克公司的QS21/MPL®脂质体佐剂系统AS01B以及以QS21脂质体作为基准进行比较时，基于抗原呈递细胞（APC）激活和细胞因子分泌，SPA14显示出最强的免疫刺激潜力，在该测定中这主要由高活性的E6020激动剂驱动。当以人巨细胞病毒糖蛋白B（gB）和五聚体复合物（PC）作为测试抗原在体内作为佐剂进行测试时，SPA14通常耐受性良好，并且在诱导小鼠和非人类灵长类动物（NHP）产生持久的巨细胞病毒中和抗体方面与AS01B一样有效。两种佐剂都促进了基于小鼠中IgG2c产生以及小鼠和NHP中IFN - γ产生的Th - 1反应的诱导，但在小鼠中，使用SPA14获得了更高水平的Th - 2细胞因子（IL - 5）以及更高的IgG1与IgG2c分泌细胞比率，这表明SPA14的佐剂特性可能比AS01B更少偏向Th - 1。从可开发性的角度来看，由于其所有脂质成分（包括E6020）在乙醇中的高溶解度，SPA14可以通过简单且可扩展的乙醇注射方法制造。此外，E6020是一种单分子、特征明确的全合成TLR4激动剂，通过优化的高产合成路线，从完全结晶的起始原料和中间体经过八个合成步骤构建而成。总体而言，我们的数据表明SPA14是一种可行的、易于制造的、有效的新型佐剂系统，可以作为一种长期稳定的液体制剂形式的即用型混合佐剂广泛应用。
