Bacterial surface display of endoglin by antigen 43 induces antitumor effectiveness via bypassing immunotolerance and inhibition of angiogenesis
Bacterial surface display of endoglin by antigen 43 induces antitumor effectiveness via bypassing immunotolerance and inhibition of angiogenesis
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DOI：
10.1002/ijc.28511
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发表时间：
2014-04
影响因子：
6.4
通讯作者：
F. Huang;Ling Li;Quan Liu;Yue-nan Li;Rui-zhen Bai;Yong-Hao Huang;Huan-ge Zhao;Jun-li Guo;Song-lin Zhou;Hua Wang;Ying-ying Lin;Guang-hong Tan
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作者：
F. Huang;Ling Li;Quan Liu;Yue-nan Li;Rui-zhen Bai;Yong-Hao Huang;Huan-ge Zhao;Jun-li Guo;Song-lin Zhou;Hua Wang;Ying-ying Lin;Guang-hong Tan
多种与血管生成相关的自身分子已被视为治疗靶点。然而，由于宿主具有产生免疫耐受的内在能力，不建议直接将自身分子用作疫苗。抗原43（Ag43）是一种在大肠杆菌中发现的表面蛋白，包含α和β亚基，其中α亚基含有多个T细胞表位。在此，我们构建了一种新型的Ag43表面展示系统（Ag43系统），用于表达Ag43嵌合蛋白，以打破针对自身分子的免疫耐受。Ag43系统由源自JM109的大肠杆菌菌株Tan109构建而成，在该菌株中Ag43基因已被敲除，并导入了表达部分Ag43基因的重组质粒（pETAg43′）。随后，将与血管生成相关的内皮糖蛋白基因的胞外结构域亚克隆到质粒pETAg43′中，得到重组质粒pETAg43′/ENDe，再用其转化Tan109以进行蛋白表达。我们发现，Ag43与内皮糖蛋白的嵌合蛋白（Ag43′/ENDe）在细菌表面表达。该嵌合蛋白可通过加热至60°C从细菌表面分离出来，且仍保留活性。我们将Ag43′/ENDe用作蛋白疫苗，发现它能够通过诱导显著的抗肿瘤活性，打破针对内皮糖蛋白的免疫耐受，并在几种肿瘤模型中抑制血管生成，且无明显副作用。这些数据表明，Ag43′/ENDe嵌合蛋白是一种有潜力的主动肿瘤免疫治疗模型疫苗，并且Ag43系统可能是制备新型疫苗的有效工具，用于打破针对其他与血管生成相关的自身分子的免疫耐受，以用于癌症治疗。
Various angiogenesis‐related self‐molecules have been considered to be therapeutic targets. However, the direct use of self‐molecules as vaccines is not recommended because of the inherent ability of the host to develop immune tolerance. Antigen 43 (Ag43) is a surface protein found in E. coli and contains an α and a β subunits, which contains multiple T epitopes in α subunit. Here we construct a novel Ag43 surface display system (Ag43 system) to express Ag43 chimeric proteins to disrupt immune tolerance against self‐molecules. The Ag43 system was constructed from an Escherichia coli strain Tan109, derived from JM109, in which the Ag43 gene was deleted and a recombinant plasmid (pETAg43′) expressing a partial Ag43 gene was introduced. The extracellular domain of angiogenesis‐related endoglin gene was then subcloned into plasmid pETAg43′, resulting in a recombinant plasmid pETAg43′/ENDe which was then used to transform Tan109 for protein expression. We found that Ag43 and endoglin chimeric protein (Ag43′/ENDe) was expressed on the bacterial surface. The chimeric protein could be separated from the bacterial surface by heating to 60°C and yet retain activity. We used Ag43′/ENDe as a protein vaccine and found that it could disrupt immune tolerance against endoglin by inducing significant antitumor activities and inhibit angiogenesis in several tumor models without significant side effects. These data suggest that Ag43′/ENDe chimeric protein is a potential model vaccine for active tumor immunotherapy, and that Ag43 system could be an effective tool for novel vaccine preparation to break immune tolerance to other angiogenesis‐related self‐molecules for cancer therapy.