Bacterial outer membrane vesicles engineered with lipidated antigens as a platform for Staphylococcus aureus vaccine
Bacterial outer membrane vesicles engineered with lipidated antigens as a platform for Staphylococcus aureus vaccine
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DOI：
10.1073/pnas.1905112116
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发表时间：
2019-10-22
影响因子：
11.1
通讯作者：
Grandi, Guido
中科院分区：
文献类型：
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作者：
Irene, Carmela;Fantappie, Laura;Grandi, Guido
细菌外膜囊泡（OMV）因其固有的佐剂性和生产过程的简单性而成为一种有趣的疫苗平台。此外，OMV 可以使用不同的合成生物学方法用外来抗原进行修饰。然而，最佳的 OMV 工程策略仍有待验证，该策略应保证大多数异源抗原的 OMV 区室化数量足以引发保护性免疫反应。在这项工作中，我们利用脂蛋白转运途径用外源蛋白改造 OMV。使用在大肠杆菌中表达的 5 种金黄色葡萄球菌保护性抗原作为与脂蛋白前导序列的融合物，我们证明所有 5 种抗原在囊泡区室中积累，浓度范围为 OMV 总蛋白的 5% 至 20%，这表明抗原脂化可能是 OMV 操作的通用方法。当以低至 0.2 μg/剂量的量给予小鼠时，工程化 OMV 会引发高、饱和的抗原特异性抗体滴度。此外，大肠杆菌BL21(DE3)Delta ompA Delta msbB Delta pagP中脂化抗原的表达会影响脂多糖结构，导致OMV的TLR4激动剂活性显着降低。这些结果，加上在金黄色葡萄球菌纽曼菌株攻击的小鼠中观察到的工程化 OMV 的有效保护活性，使得 5-combo-OMV 成为有希望在临床中进行测试的候选疫苗。
Bacterial outer membrane vesicles (OMVs) represent an interesting vaccine platform for their built-in adjuvanticity and simplicity of production process. Moreover, OMVs can be decorated with foreign antigens using different synthetic biology approaches. However, the optimal OMV engineering strategy, which should guarantee the OMV compartmentalization of most heterologous antigens in quantities high enough to elicit protective immune responses, remains to be validated. In this work we exploited the lipoprotein transport pathway to engineer OMVs with foreign proteins. Using 5 Staphylococcus aureus protective antigens expressed in Escherichia coli as fusions to a lipoprotein leader sequence, we demonstrated that all 5 antigens accumulated in the vesicular compartment at a concentration ranging from 5 to 20% of total OMV proteins, suggesting that antigen lipidation could be a universal approach for OMV manipulation. Engineered OMVs elicited high, saturating antigen-specific antibody titers when administered to mice in quantities as low as 0.2 mu g/dose. Moreover, the expression of lipidated antigens in E. coli BL21(DE3)Delta ompA Delta msbB Delta pagP was shown to affect the lipopolysaccharide structure, with the result that the TLR4 agonist activity of OMVs was markedly reduced. These results, together with the potent protective activity of engineered OMVs observed in mice challenged with S. aureus Newman strain, makes the 5-combo-OMVs a promising vaccine candidate to be tested in clinics.