School of Biological Sciences, University of the Punjab, Lahore, Pakistan.
Department of Biology, Lahore University of Management Sciences (LUMS), Lahore, Pakistan.
PLoS One. 2022 Sep 29;17(9):e0271126. doi: 10.1371/journal.pone.0271126. eCollection 2022.
Non availability of effective anti-TB vaccine impedes TB control which remains a crucial global health issue. A fusion molecule based on immunogenic antigens specific to different growth phases of Mycobacterium tuberculosis can enhance T-cell responses required for developing a potent vaccine. In this study, six antigens including EspC, TB10.4, HspX, PPE57, CFP21 and Rv1352 were selected for constructing EspC-TB10.4 (bifu25), TnCFP21-Rv1352 (bifu29), HspX-EspC-TB10.4 (trifu37), HspX-TnCFP21-Rv1352 (trifu44) and HspX-EspC-TB10.4-PPE57 (tetrafu56) fusion proteins. Th1-cell epitopes of EspC, PPE57 and Rv1352 antigens were predicted for the first time using different in silico tools. The fusion molecule tetrafu56, which consisted of antigens from both the replicating and the dormant stages of Mtb, induced a release of 397 pg/mL of IFN-γ from PBMCs of the active TB patients. This response was comparable to the response obtained with cocktail of the component antigens (396 pg/mL) as well as to the total of the responses obtained separately for each of its component antigens (388 pg/mL). However, PBMCs from healthy samples in response to tetrafu56 showed IFN-γ release of only 26.0 pg/mL Thus a previous exposure of PBMCs to Mtb antigens in TB plasma samples resulted in 15-fold increase in IFN-γ response to tetrafu56 as compared to the PBMCs from the healthy controls. Hence, most of the T-cell epitopes of the individual antigens seem to be available for T-cell interactions in the form of the fusion. Further investigation in animal models should substantiate the immune efficacy of the fusion molecule. Thus, the fusion tetrafu56 seems to be a potential candidate for developing an effective multistage vaccine against TB.
有效抗结核疫苗的缺乏阻碍了结核病控制，这仍然是一个至关重要的全球健康问题。一种基于分枝杆菌不同生长阶段特异性免疫原性抗原的融合分子可以增强用于开发有效疫苗所需的 T 细胞反应。在这项研究中，选择了 EspC、TB10.4、HspX、PPE57、CFP21 和 Rv1352 等 6 种抗原用于构建 EspC-TB10.4（bifu25）、TnCFP21-Rv1352（bifu29）、HspX-EspC-TB10.4（trifu37）、HspX-TnCFP21-Rv1352（trifu44）和 HspX-EspC-TB10.4-PPE57（tetrafu56）融合蛋白。首次使用不同的计算工具预测了 EspC、PPE57 和 Rv1352 抗原的 Th1 细胞表位。融合分子 tetrafu56 由 Mtb 复制和休眠阶段的抗原组成，从活动性结核病患者的 PBMC 中诱导释放 397 pg/mL 的 IFN-γ。这一反应与鸡尾酒成分抗原（396 pg/mL）获得的反应以及与每个成分抗原单独获得的总反应（388 pg/mL）相当。然而，tetrafu56 对健康样本的 PBMC 仅显示 IFN-γ 释放 26.0 pg/mL。因此，与健康对照组相比，PBMC 之前接触过结核血浆样品中的 Mtb 抗原，导致对 tetrafu56 的 IFN-γ 反应增加了 15 倍。因此，单个抗原的大多数 T 细胞表位似乎都可以以融合的形式用于 T 细胞相互作用。在动物模型中的进一步研究应该证实融合分子的免疫效果。因此，融合 tetrafu56 似乎是开发针对结核病的有效多阶段疫苗的潜在候选者。
