School of Pharmacy, The University of Queensland, 20 Cornwall Street, Woolloongabba, Queensland 4102, Australia.
Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland 4072, Australia.
ACS Infect Dis. 2020 Jul 10;6(7):1770-1782. doi: 10.1021/acsinfecdis.0c00047. Epub 2020 Jun 1.
Subunit vaccines composed of protein antigens covalently attached to Toll-like receptor (TLR) agonists elicit superior immune responses compared to mixtures of antigens and TLR agonists. Among different conjugation approaches, enzyme-mediated ligation is one of the few that provides an opportunity for the generation of homogeneous, molecularly defined products in which protein antigens are maintained with native structures, which is most critical to elicit protective immune responses upon vaccination. Four highly conserved protein antigens from Group A (GAS) have the potential to be safe and efficacious vaccine candidates. After a TLR2 agonist fibroblast-stimulating lipopeptide-1 (FSL-1) was successfully attached onto each antigen using sortase A and techniques for their purification were developed, a combination vaccine containing interleukin 8 (IL-8) protease ( cell envelope proteinase [SpyCEP]), Group A Streptococcal C5a peptidase (SCPA), anchorless virulence factor arginine deiminase (ADI), and trigger factor (TF)-TLR2 conjugates was produced. This combination was assessed for immunity in mice and compared with mixtures of the four antigens with FSL-1 or alum. High titer antigen-specific IgG antibodies were detected from all vaccine groups, with antibodies elicited from FSL-1 conjugates around 10-fold higher compared to the FSL-1 mixture group. Furthermore, the FSL-1 conjugates afforded a more balanced T1/T2 immune response than the alum-adjuvanted group, suggesting that this combination vaccine represents a promising candidate for the prevention of GAS diseases. Thus, we established a conjugation platform that allows for the production of defined, site-specific antigen-adjuvant conjugates, which maintain the native three-dimensional structure of antigens and can be potentially applied to a variety of protein antigens.
亚单位疫苗由共价连接到 Toll 样受体 (TLR) 激动剂的蛋白抗原组成，与抗原和 TLR 激动剂混合物相比，能引发更优的免疫反应。在不同的连接方法中，酶介导的连接是少数几种能够产生均一、分子定义明确的产物的方法之一，其中蛋白抗原保持天然结构，这对于引发保护性免疫反应至关重要。A 组（GAS）的四种高度保守的蛋白抗原具有成为安全有效的疫苗候选物的潜力。成功地使用 sortase A 将 TLR2 激动剂纤维母细胞刺激脂肽-1（FSL-1）连接到每种抗原上，并开发了它们的纯化技术后，一种含有白细胞介素 8（IL-8）蛋白酶（细胞外膜蛋白酶[SpyCEP]）、A 组链球菌 C5a 肽酶（SCPA）、无锚定毒力因子精氨酸脱氨酶（ADI）和触发因子（TF）-TLR2 缀合物的组合疫苗被生产出来。在小鼠中评估了这种组合疫苗的免疫效果，并将其与四种抗原与 FSL-1 或铝佐剂的混合物进行了比较。从所有疫苗组中都检测到了高滴度的抗原特异性 IgG 抗体，FSL-1 缀合物引发的抗体比 FSL-1 混合物组高约 10 倍。此外，FSL-1 缀合物比铝佐剂组提供了更平衡的 T1/T2 免疫反应，表明这种组合疫苗是预防 GAS 疾病的有前途的候选物。因此，我们建立了一个连接平台，允许生产具有定义的、位点特异性的抗原-佐剂缀合物，这些缀合物保持抗原的天然三维结构，并可能应用于各种蛋白抗原。
