一种靶向钙结合蛋白S100A9重组疫苗的构建及其抗肿瘤活性研究

Construction and anti-tumor efficacy of a peptide vaccine that targets calcium-binding protein S100A9

钙结合蛋白S100A9与炎症发生与肿瘤侵袭密切相关,是髓系来源的抑制性细胞(myeloid-derived suppressor cell, MDSC)的特异性标志物之一。本研究以霍乱毒素B亚基(CTB)五聚体为载体构建了一种靶向小鼠钙结合蛋白S100A9的重组多肽疫苗CTB-S100A9,并在大肠杆菌分泌表达系统中获得表达。经纯化后的重组CTBS100A9五聚体蛋白辅以氢氧化铝佐剂免疫小鼠后能打破自身免疫耐受产生高滴度的S100A9抗体。在4T1小鼠乳腺癌的预防及治疗模型中, CTB-S100A9疫苗均能够有效抑制肿瘤生长。进一步发现CTB-S100A9疫苗能够有效减少荷瘤小鼠外周血中Treg细胞的含量及粒细胞来源的MDSC,逆转抑制性肿瘤免疫环境,增强抗肿瘤免疫应答。本研究的动物实验都是在南京中医药大学附属中西医结合医院动物伦理委员会批准的动物护理和方案下进行。该研究表明, CTB-S100A9是一种良好的靶向肿瘤免疫环境的重组疫苗,具有较大临床应用的潜力。

Calcium-binding protein S100 A9 is closely related to inflammation and tumor invasion,and is one of the specific markers of myeloid-derived suppressor cells(MDSC).In this study,a recombinant polypeptide vaccine CTB-S100A9 targeting mouse calcium-binding protein S100 A9 was constructed by fusion cholera toxin B subunit(CTB)with S100A9 gene.The CTB-S100A9 fusion protein was expressed in E coli.and purified by Ni+affinity chromatography.Vaccinate the purified recombinant CTB-S100A9 protein supplemented with aluminum hydroxide adjuvant can break the autoimmune tolerance and produce high titer of S100A9 antibody in mice.Moreover,the S100A9 antibody produced by CTB-S100A9 vaccination is more specific and does not cross-react with S100A8.In the mouse 4 T1 breast cancer model,CTB-S100 A9 vaccination not only has significant tumor prevention effects,but also has significant tumor therapeutic effects.In addition,CTB-S100A9 significantly inhibited lung metastasis in 4 T1 mice breast cancer model.Further analysis by flow cytometry showed that CTB-S100A9 vaccination can significantly reduce the tumor induced Treg cells and granulocyte-derived MDSC in 4 T1 mice model,and reverse the tumor immunosuppressive environment,thereby promote the anti-tumor efficacy.The animal experiments in this study were carried out under the animal care guidelines approved by the Animal Ethics Committee of the Affiliated Hospital of Integrated Traditional Chinese and Western Medicine,Nanjing University of Chinese Medicine.This study shows that CTB-S100A9 is a good recombinant vaccine that targets the tumor immunesuppression environment and has great potential for the future clinical application.