Cheng Peng, Wang Liang, Gong Wenping
Tuberculosis Prevention and Control Key Laboratory/Beijing Key Laboratory of New Techniques of Tuberculosis Diagnosis and Treatment, Senior Department of Tuberculosis, The 8th Medical Center of PLA General Hospital, Beijing, China.
Hebei North University, Zhangjiakou, China.
Front Microbiol. 2022 Jun 28;13:947852. doi: 10.3389/fmicb.2022.947852. eCollection 2022.
Latent tuberculosis infection (LTBI) is the primary source of active tuberculosis (ATB), but there are no specific methods for diagnosing and preventing LTBI.
Dominant T and B cell epitopes predicted from five antigens related to LTBI and region of difference (LTBI-RD) were used to construct a novel polypeptide molecule (PPM). Then, the physicochemical properties, secondary structure, tertiary structure of the PPM, and its binding ability to toll-like receptor 2 (TLR2) and TLR4 were analyzed by bioinformatics tools. Finally, immune stimulation and expression optimization of the PPM were carried out.
Four helper T lymphocytes (HTL) epitopes, five cytotoxic T lymphocytes (CTL) epitopes, and three B cell epitopes were predicted and screened from five LTBI-RD related antigens. These epitopes were connected in series with linkers and adjuvants to construct a novel PPM termed C543P. The results indicated that antigenicity and immunogenicity scores of the C543P candidate were 0.936399 and 1.36469, respectively. The structural analysis results showed that the C543P candidate had good stability. Its secondary structure contained 43.6% α-helix, the Z-score after tertiary structure optimization was -7.9, and the Ramachandran diagram showed that 88.77% amino acid residues of the C543P candidate were in the allowable region. Furthermore, the C543P candidate showed an excellent affinity to TLR2 (-1091.7kcal/mol) and TLR4 (-1102.7kcal/mol). In addition, we also analyzed the immunological characteristics of the C543P candidate. Immune stimulation prediction showed that the C543P candidate could effectively activate T and B lymphocytes and produce high levels of Th1 cytokines such as IFN-γ and IL-2.
We constructed a novel PPM with acceptable antigenicity, immunogenicity, stability, and ability to induce robust immune responses. This study provides a new diagnostic biomarker or peptides-based vaccine for LTBI diagnosis and prevention.
潜伏性结核感染（LTBI）是活动性结核病（ATB）的主要来源，但目前尚无诊断和预防LTBI的特异性方法。
利用从与LTBI相关的五种抗原及差异区域（LTBI-RD）预测的主要T和B细胞表位构建一种新型多肽分子（PPM）。然后，通过生物信息学工具分析PPM的理化性质、二级结构、三级结构及其与Toll样受体2（TLR2）和TLR4的结合能力。最后，进行PPM的免疫刺激和表达优化。
从五种与LTBI-RD相关的抗原中预测并筛选出四个辅助性T淋巴细胞（HTL）表位、五个细胞毒性T淋巴细胞（CTL）表位和三个B细胞表位。这些表位通过连接子和佐剂串联，构建出一种名为C543P的新型PPM。结果表明，C543P候选物的抗原性和免疫原性评分分别为0.936399和1.36469。结构分析结果显示，C543P候选物具有良好的稳定性。其二级结构包含43.6%的α-螺旋，三级结构优化后的Z值为-7.9，拉氏图显示C543P候选物88.77%的氨基酸残基位于允许区域。此外，C543P候选物对TLR2（-1091.7kcal/mol）和TLR4（-1102.7kcal/mol）表现出优异的亲和力。此外，我们还分析了C543P候选物的免疫学特性。免疫刺激预测表明，C543P候选物可有效激活T和B淋巴细胞，并产生高水平的Th1细胞因子，如IFN-γ和IL-2。
我们构建了一种具有可接受的抗原性、免疫原性、稳定性以及诱导强烈免疫反应能力的新型PPM。本研究为LTBI的诊断和预防提供了一种新的诊断生物标志物或基于肽的疫苗。
