Azevedo-Silva João, Amorim Manuela, Tavares-Valente Diana, Sousa Pedro, Mohamath Raodoh, Voigt Emily A, Guderian Jeffrey A, Kinsey Robert, Viana Sofia, Reis Flávio, Pintado Manuela E, Paddon Christopher J, Fox Christopher B, Fernandes João C
CBQF-Centro de Biotecnologia e Química Fina-Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa, 4169-005, Porto, Portugal.
Access to Advanced Health Institute, Formerly Infectious Disease Research Institute, Seattle, WA, USA.
Eur J Pharm Biopharm. 2024 Dec;205:114538. doi: 10.1016/j.ejpb.2024.114538. Epub 2024 Oct 24.
Vaccine adjuvants are important for enhancing vaccine efficacy, and although aluminium salts (Alum) are the most used, their limited ability to induce specific immune responses has spurred the search for new adjuvants. However, many adjuvants fail during product development due to manufacturability, supply, stability, or safety concerns. This work hypothesizes that protein-free yeast glucans can be used as vaccine adjuvants due to their known immunostimulatory activity and high abundancy. Thus, high molecular weight glucans with over 99% purity, comprising 64-70% β-glucans and 29-35% α-glucans, were extracted from a wild-type yeast and an engineered yeast to produce a steviol glycoside. These glucans underwent carboxymethylation to enhance solubility. Both water-dispersible and particulate glucans were evaluated as adjuvants, either alone or in combination with Alum or squalene stable emulsion (SE), for a SARS-CoV-2 vaccine. The study demonstrated that glucans triggered a robust immune response and enhanced the effects of Alum and SE when used in combination, both in vitro and in vivo. Water-dispersible glucans combined with Alum, and particulate glucans combined with SE, increased the production of specific antibodies against SARS-CoV-2 spike protein and enhanced serum neutralization titers against SARS-CoV-2 pseudovirus. Furthermore, the results indicated that larger molecular weight glucans from engineered yeast exhibited stronger immunogenic activity in comparison to wild-type yeast glucans. In conclusion, appropriately formulated glucans have the potential to be scalable, low-cost vaccine adjuvants, potentially overcoming the limitations of current adjuvants.
疫苗佐剂对于提高疫苗效力很重要，尽管铝盐（明矾）是最常用的，但它们诱导特异性免疫反应的能力有限，这促使人们寻找新的佐剂。然而，由于可制造性、供应、稳定性或安全性等问题，许多佐剂在产品开发过程中失败了。这项研究假设，无蛋白酵母葡聚糖因其已知的免疫刺激活性和高丰度，可作为疫苗佐剂。因此，从野生型酵母和一种用于生产甜菊糖苷的工程酵母中提取了纯度超过99%的高分子量葡聚糖，其中包含64-70%的β-葡聚糖和29-35%的α-葡聚糖。这些葡聚糖经过羧甲基化以提高溶解度。将水溶性和颗粒状葡聚糖单独或与明矾或角鲨烯稳定乳液（SE）联合用作一种严重急性呼吸综合征冠状病毒2（SARS-CoV-2）疫苗的佐剂进行评估。该研究表明，葡聚糖可引发强烈的免疫反应，并且在体外和体内与明矾和SE联合使用时可增强其效果。水溶性葡聚糖与明矾联合，颗粒状葡聚糖与SE联合，可增加针对SARS-CoV-2刺突蛋白的特异性抗体的产生，并提高针对SARS-CoV-2假病毒的血清中和效价。此外，结果表明，与野生型酵母葡聚糖相比，来自工程酵母的分子量更大的葡聚糖表现出更强的免疫原性。总之，适当配方的葡聚糖有潜力成为可扩展、低成本的疫苗佐剂，有可能克服当前佐剂的局限性。
