Delivery of foreign antigens by engineered outer membrane vesicle vaccines
Delivery of foreign antigens by engineered outer membrane vesicle vaccines
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DOI：
10.1073/pnas.0805532107
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发表时间：
2010-02-16
影响因子：
11.1
通讯作者：
Putnam, David
中科院分区：
文献类型：
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作者：
Chen, David J.;Osterrieder, Nikolaus;Putnam, David
随着新的疾病威胁的出现和现有病原体对常规干预措施的抵抗力增强，人们越来越重视开发疫苗以诱导保护性免疫反应。鉴于其令人钦佩的安全记录，蛋白质亚单位疫苗具有广泛免疫的吸引力，但其缺点包括免疫原性差和制造成本高。我们在此表明，工程大肠杆菌外膜囊泡（OMVs）是一种易于纯化的疫苗递送系统，能够在不添加佐剂的情况下大大增强低免疫原性蛋白抗原的免疫原性。利用绿色荧光蛋白（GFP）作为模型亚基抗原，将绿色荧光蛋白与细菌溶血素ClyA基因融合产生嵌合蛋白，在免疫小鼠中引发较强的抗GFP抗体滴度，而单独用GFP免疫则不产生这种滴度。利用ClyA对omv的特异性分泌，发现cla - gfp融合在omv中定位，从而产生工程重组omv。用工程OMV配方免疫的小鼠的抗gfp体液反应与单独纯化的ClyA-GFP融合蛋白的反应没有区别，等于纯化的蛋白质吸收到氢氧化铝（标准佐剂）中。与目前的做法相比，一个重大的改进是，含有ClyA-GFP的工程omv很容易通过超离心分离，有效地消除了从细胞培养表达系统中纯化抗原的需要。当与ClyA融合时，各种各样的外源蛋白可以在功能上定位于omv，这项工作标志着omv作为新一代预防性和治疗性疫苗的强大和可调技术平台的可能性。
As new disease threats arise and existing pathogens grow resistant to conventional interventions, attention increasingly focuses on the development of vaccines to induce protective immune responses. Given their admirable safety records, protein subunit vaccines are attractive for widespread immunization, but their disadvantages include poor immunogenicity and expensive manufacture. We show here that engineered Escherichia coli outermembrane vesicles (OMVs) are an easily purified vaccine-delivery system capable of greatly enhancing the immunogenicity of a low-immunogenicity protein antigen without added adjuvants. Using green-fluorescent protein (GFP) as the model subunit antigen, genetic fusion of GFP with the bacterial hemolysin ClyA resulted in a chimeric protein that elicited strong anti-GFP antibody titers in immunized mice, whereas immunization with GFP alone did not elicit such titers. Harnessing the specific secretion of ClyA to OMVs, the ClyA-GFP fusion was found localized in OMVs, resulting in engineered recombinant OMVs. The anti-GFP humoral response in mice immunized with the engineered OMV formulations was indistinguishable from the response to the purified ClyA-GFP fusion protein alone and equal to purified proteins absorbed to aluminum hydroxide, a standard adjuvant. In a major improvement over current practice, engineered OMVs containing ClyA-GFP were easily isolated by ultracentrifugation, effectively eliminating the need for laborious antigen purification from cell-culture expression systems. With the diverse collection of heterologous proteins that can be functionally localized with OMVs when fused with ClyA, this work signals the possibility of OMVs as a robust and tunable technology platform for a new generation of prophylactic and therapeutic vaccines.