Toyé Rayana Maryse, Cohen Damien, Pujol Flor Helene, Sow-Sall Amina, Lô Gora, Hoshino Kunikazu, Mizokami Masashi, Zoulim Fabien, Lemoine Maud, Touré-Kane Coumba, Chemin Isabelle
Institut National de la Santé et de la Recherche Médicale (Inserm) U1052, CRCL, 151 Cours Albert Thomas, 69003 Lyon, France.
Institut de Recherche en Santé, de Surveillance Epidémiologique et de Formation (Iressef), BP 7325, Diamniadio 20000, Senegal.
Microorganisms. 2021 Mar 17;9(3):623. doi: 10.3390/microorganisms9030623.
Hepatitis B virus (HBV) classification comprises up to 10 genotypes with specific geographical distribution worldwide, further subdivided into 40 subgenotypes, which have different impacts on liver disease outcome. Though extensively studied, the classification of subgenotype A sequences remains ambiguous. This study aimed to characterize HBV isolates from West African patients and propose a more advanced classification of subgenotype A. Fourteen HBV full-length genome sequences isolated from patients from The Gambia and Senegal were obtained and phylogenetically analyzed. Phylogenetic analysis of HBV genotype A sequences isolated from Senegalese and Gambian patients exhibited separate clusters from the other known and confirmed subgenotypes A (A1, A2, A6). Most of the sequences (10/14) clustered with an isolate from Cuba, reported as subgenotype A4 (supported by maximal bootstrap value). Four isolates from The Gambia and Senegal clustered separately from all other subgenotypes and samples sequenced in the study. Three of which from The Gambia, designated as an expanding clade of subgenotype A4, exhibited a mean inter-subgenotypic nucleotide divergence over the entire genome sequence higher than 4% in comparison with the other subgenotypes and the other isolates sequenced in the study, except with subgenotype A4 isolates (3.9%), and this was supported by a maximal bootstrap value. The last one from Senegal seemed to be an expanding subgenotype close to the new clade of A4. Amino acid analysis unveiled a novel motif specific to these isolates. This study revealed an expanding evolution of HBV subgenotype A and novel amino acid motifs. It also highlighted the need for a consensus regarding the analysis and classification of HBV sequences.
乙型肝炎病毒（HBV）分类包括多达10种基因型，在全球具有特定的地理分布，进一步细分为40个亚型，它们对肝脏疾病的转归有不同影响。尽管已进行了广泛研究，但A型亚型序列的分类仍不明确。本研究旨在对来自西非患者的HBV分离株进行特征分析，并提出更先进的A型亚型分类。从冈比亚和塞内加尔患者中分离出14个HBV全长基因组序列，并进行系统发育分析。对从塞内加尔和冈比亚患者中分离出的HBV A基因型序列进行的系统发育分析显示，它们与其他已知且已确认的A型亚型（A1、A2、A6）形成了独立的聚类。大多数序列（10/14）与来自古巴的一株分离株聚类，该分离株被报告为A4亚型（最大自展值支持）。来自冈比亚和塞内加尔的4株分离株与本研究中测序的所有其他亚型和样本分别聚类。其中3株来自冈比亚，被指定为A4亚型的一个扩展分支，与其他亚型以及本研究中测序的其他分离株相比，其在整个基因组序列上的平均亚型间核苷酸差异高于4%，但与A4亚型分离株相比为（3.9%），且这得到了最大自展值的支持。来自塞内加尔的最后一株分离株似乎是一个接近A4新分支的扩展亚型。氨基酸分析揭示了这些分离株特有的一个新基序。本研究揭示了HBV A亚型的扩展进化和新的氨基酸基序。它还强调了在HBV序列分析和分类方面达成共识的必要性。
