DS Kothari Central Interdisciplinary Research Centre, Department of Zoology, Miranda House, University of Delhi, Delhi 110007, India.
DS Kothari Central Interdisciplinary Research Centre, Department of Zoology, Miranda House, University of Delhi, Delhi 110007, India.
Eur J Pharm Sci. 2022 Jan 1;168:106051. doi: 10.1016/j.ejps.2021.106051. Epub 2021 Oct 29.
Since decades now, Tuberculosis (TB) is among the leading cause of death globally. Innovative and extensive research strategies are necessary to lower TB incidence and achieve the End TB Strategy milestone. Epitope-based vaccine designing and development provides a promising solution with high efficacy and effectiveness. Mining of less studied genes of Mycobacterium tuberculosis (Mtb) is crucial for recognizing potential antigenic peptide epitopes which can mount protective immune response in host. Many proteins from ESX associated Proline-Glutamate (PE)/ Proline-Proline-Glutamate (PPE) family are virulence factors and alter host mediated immune response against the pathogen. In the present study, we have targeted 34 late stage expressing (being expressed at 90 days) PE/PPE proteins of Mtb for prediction and identification of promiscuous, immunogenic and cross-reactive CD4 T cell specific epitopes. We found a total of 149 promiscuous and cross-reactive epitopes out of which 42 were antigenic as well. Further, we shortlisted top 10 Promiscuous, Cross-reactive CD4 T cell specific, Antigenic Peptide Epitopes (PCAPEs) which were characterized to be non-allergenic and pro-inflammatory cytokine inducing in nature. These epitopes also showed strong binding affinity for CD8 T cell restricted Major Histo-compatibility Complex (MHC) class I alleles. Additionally, these PCAPEs showed wide population coverage of 99.6% globally for both MHC class I and class II alleles. Molecular docking studies were conducted to confirm the affinity of these shortlisted peptides for widely occurring MHC alleles. Additionally, we performed codon adaptation and in silico cloning of the recombinant vaccine construct incorporating EsxA (ESAT-6) as an adjuvant and the 10 selected PCAPEs joined by linkers. The recombinant vaccine construct showed strong affinity for Toll-like receptor2 (TLR2) immune receptor in docking studies. In silico prediction based study using C-ImmSim server shows significant population of Th1 type immune cells with memory cells lasting for months in response to our vaccine administration. Since, majority of TB vaccines under clinical trials are antigens expressed at early stages; a combinatorial approach inclusive of peptide epitopes derived from proteins being expressed at all stages could be a promising strategy to design and develop effective TB vaccine. Synthesis and experimental validation of this multi-epitopic recombinant TB vaccine construct may result in an effective vaccine to confer protection against Mtb.
几十年来,结核病(TB)一直是全球主要死因之一。为了降低结核病的发病率并实现终结结核病战略的里程碑,需要创新和广泛的研究策略。基于表位的疫苗设计和开发提供了一种有前途的解决方案,具有高效和有效性。挖掘结核分枝杆菌(Mtb)中研究较少的基因对于识别潜在的抗原肽表位至关重要,这些表位可以在宿主中引发保护性免疫反应。ESX 相关脯氨酸-谷氨酸(PE)/脯氨酸-脯氨酸-谷氨酸(PPE)家族的许多蛋白质都是毒力因子,会改变宿主对病原体的介导免疫反应。在本研究中,我们针对 Mtb 的 34 种晚期表达(在 90 天时表达)的 PE/PPE 蛋白进行了预测和鉴定,以寻找广谱、免疫原性和交叉反应性的 CD4 T 细胞特异性表位。我们总共发现了 149 个广谱和交叉反应性表位,其中 42 个是抗原性的。此外,我们还筛选出了前 10 个广谱、交叉反应性 CD4 T 细胞特异性、抗原性肽表位(PCAPEs),这些表位具有非变应原性和诱导促炎细胞因子的特性。这些表位还显示出与 CD8 T 细胞受限的主要组织相容性复合物(MHC)I 类等位基因强烈结合的亲和力。此外,这些 PCAPEs 显示出对 MHC I 和 II 类等位基因的广泛人群覆盖率,全球范围内均达到 99.6%。进行了分子对接研究以确认这些筛选出的肽与广泛存在的 MHC 等位基因的亲和力。此外,我们对包含 EsxA(ESAT-6)作为佐剂和通过接头连接的 10 个选定的 PCAPEs 的重组疫苗构建体进行了密码子适应和计算机克隆。在对接研究中,重组疫苗构建体与 Toll 样受体 2(TLR2)免疫受体表现出强烈的亲和力。使用 C-ImmSim 服务器进行基于预测的计算研究表明,在我们的疫苗接种后,会有大量 Th1 型免疫细胞存在,记忆细胞可以持续数月。由于大多数正在临床试验中的结核病疫苗都是早期表达的抗原;因此,包括在所有阶段表达的蛋白质衍生的肽表位的组合方法可能是设计和开发有效结核病疫苗的一种有前途的策略。这种多表位重组结核疫苗构建体的合成和实验验证可能会产生一种有效的疫苗,以提供对 Mtb 的保护。