南非基因编码分枝杆菌抗原 Rv2660 保守性和 H56 多阶段疫苗高预测人群覆盖率。
Conservation in gene encoding Mycobacterium tuberculosis antigen Rv2660 and a high predicted population coverage of H56 multistage vaccine in South Africa.
机构信息
Department of Epidemiology, School of Public Health, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109-2029, United States.
Department of Computational Medicine and Bioinformatics, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109-2029, United States.
出版信息
Infect Genet Evol. 2017 Nov;55:244-250. doi: 10.1016/j.meegid.2017.09.023. Epub 2017 Sep 21.
H56/AERAS-456+IC31 (H56), composed of two early secretion proteins, Ag85B and ESAT-6, and a latency associated protein, Rv2660, and the IC31 Intercell adjuvant, is a new fusion subunit vaccine candidate designed to induce immunity against both new infection and reactivation of latent tuberculosis infection. Efficacy of subunit vaccines may be affected by the diversity of vaccine antigens among clinical strains and the extent of recognition by the diverse HLA molecules in the recipient population. Although a previous study showed the conservative nature of Ag85B- and ESAT-6-encoding genes, genetic diversity of Rv2660c that encodes RV2660 is largely unknown. The population coverage of H56 as a whole yet remains to be assessed. The present study was conducted to address these important knowledge gaps. DNA sequence analysis of Rv2660c found no variation among 83 of the 84 investigated clinical strains belonging to four genetic lineages. H56 was predicted to have as high as 99.6% population coverage in the South Africa population using the Immune Epitope Database (IEDB) Population Coverage Tool. Further comparison of H56 population coverage between South African Blacks and Caucasians based on the phenotypic frequencies of binding MHC Class I and Class II supertype alleles found that all of the nine MHC-I and six of eight MHC-II human leukocyte antigen (HLA) supertype alleles analyzed were significantly differentially expressed between the two subpopulations. This finding suggests the presence of race-specific functional binding motifs of MHC-I and MHC-II HLA alleles, which, in turn, highlights the importance of including diverse populations in vaccine clinical evaluation. In conclusion, H56 vaccine is predicted to have a promising population coverage in South Africa; this study demonstrates the utility of integrating comparative genomics and bioinformatics in bridging animal and clinical studies of novel TB vaccines.
H56/AERAS-456+IC31(H56)由两种早期分泌蛋白(Ag85B 和 ESAT-6)、潜伏相关蛋白 Rv2660 和 IC31 细胞间佐剂组成,是一种新的融合亚单位疫苗候选物,旨在诱导对新感染和潜伏结核感染再激活的免疫。亚单位疫苗的功效可能受到临床株疫苗抗原多样性和受者人群中不同 HLA 分子识别程度的影响。虽然先前的研究表明 Ag85B 和 ESAT-6 编码基因具有保守性,但编码 RV2660 的 Rv2660c 的遗传多样性在很大程度上尚不清楚。H56 作为一个整体的人群覆盖率仍有待评估。本研究旨在解决这些重要的知识空白。对 84 株临床株中的 83 株 Rv2660c 的 DNA 序列分析发现,属于四个遗传谱系的所有株均无变异。使用免疫表位数据库(IEDB)人群覆盖率工具预测,H56 在南非人群中的人群覆盖率高达 99.6%。进一步比较南非黑人与白人群体中 H56 的人群覆盖率,基于结合 MHC Ⅰ类和Ⅱ类超型等位基因的表型频率,发现分析的 9 个 MHC-Ⅰ和 6 个 MHC-Ⅱ人类白细胞抗原(HLA)超型等位基因均在两个亚群之间存在显著差异表达。这一发现表明 MHC-Ⅰ和 MHC-Ⅱ HLA 等位基因存在种族特异性的功能结合基序,这反过来强调了在疫苗临床评估中纳入不同人群的重要性。总之,H56 疫苗在南非的人群覆盖率预测前景乐观;本研究证明了整合比较基因组学和生物信息学在连接新型结核疫苗的动物和临床研究中的实用性。