Antibody-mediated immunity induced by engineered Escherichia coli OMVs carrying heterologous antigens in their lumen.
Antibody-mediated immunity induced by engineered Escherichia coli OMVs carrying heterologous antigens in their lumen.
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DOI：
10.3402/jev.v3.24015
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发表时间：
2014
影响因子：
16
通讯作者：
Grandi G
中科院分区：
文献类型：
--
作者：
Fantappiè L;de Santis M;Chiarot E;Carboni F;Bensi G;Jousson O;Margarit I;Grandi G
革兰氏阴性菌的外膜囊泡（OMV）由于其内在的佐剂性和作为异源抗原载体的潜在用途而作为疫苗平台越来越受到关注。这两个特性提供了制造高效、易于生产多价疫苗的机会。OMV可以通过将蛋白质表达靶向到OMV生产菌株的外膜或周质来负载外源抗原。周质表达是简单且相对有效的，但导致重组抗原在OMV的管腔中积累，并且携带内化抗原的OMV诱导抗原特异性抗体应答的能力仅被少量研究，并且被认为是次优的。我们系统地分析了在其管腔中携带不同异源抗原的OMV诱导的抗体应答的定性和定量方面。将A群链球菌（GAS）Slo、SpyCEP、Spy 0269和B群链球菌（GBS）SAM_1372与OmpA前导序列融合用于分泌并在大肠杆菌中表达。纯化来自重组菌株的OMV并测试免疫原性和保护活性。所有蛋白质以其天然构象掺入OMV腔中。在小鼠免疫后，OMV诱导针对重组蛋白的高功能性抗体滴度。此外，用Slo-OMV和SpyCEP-OMV免疫保护小鼠免受GAS致死攻击。通过周质表达将抗原递送至囊泡腔的效率，以及携带内化重组抗原的OMV的令人惊讶的高免疫原性和保护活性进一步增强了OMV作为疫苗平台的潜力。
Outer membrane vesicles (OMVs) from Gram-negative bacteria are gaining increasing attention as vaccine platform for their built-in adjuvanticity and for their potential use as carriers of heterologous antigens. These 2 properties offer the opportunity to make highly effective, easy to produce multi-valent vaccines. OMVs can be loaded with foreign antigens by targeting protein expression either to the outer membrane or to the periplasm of the OMV-producing strain. Periplasmic expression is simple and relatively efficient but leads to the accumulation of recombinant antigens in the lumen of OMVs and the ability of OMVs carrying internalized antigens to induce antigen-specific antibody responses has been only marginally investigated and is considered to be sub-optimal. We have systematically analyzed in qualitative and quantitative terms antibody responses induced by OMVs carrying different heterologous antigens in their lumen. Group A Streptococcus (GAS) Slo, SpyCEP, Spy0269 and Group B Streptococcus (GBS) SAM_1372 were fused to the OmpA leader sequence for secretion and expressed in Escherichia coli. OMVs from the recombinant strains were purified and tested for immunogenicity and protective activity. All proteins were incorporated into the OMVs lumen in their native conformation. Upon mice immunization, OMVs induced high functional antibody titers against the recombinant proteins. Furthermore, immunization with Slo-OMVs and SpyCEP-OMVs protected mice against GAS lethal challenge. The efficiency of antigen delivery to the vesicular lumen via periplasmic expression, and the surprisingly high immunogenicity and protective activity of OMVs carrying internalized recombinant antigens further strengthens the potential of OMVs as vaccine platform.