Identification of Six Putative Novel Human Papillomaviruses (HPV) and Characterization of Candidate HPV Type 87

Six putative novel human papillomavirus (HPV) types were detected by using general primers for a conserved L1 HPV region in patients examined in gynecologic centers. One of the isolates, detected in samples from 4 patients with koilocytic atypia at cervical cytology (3 of whom were also infected with human immunodeficiency virus type 1), was completely sequenced, identified as a new HPV genotype, and designated candidate HPV87 (candHPV87) by the Reference Center for Human Papillomavirus. candHPV87 shows the classic HPV genome organization and the absence of a functional E5 coding region. Phylogenetic analysis documented that the candHPV87 genome clusters within the A3 group of HPVs, together with HPV61, HPV72, HPV83, HPV84 and candHPV86, which have been completely sequenced, and a number of other putative novel genotypes (two of which are described in this work), which have been partially characterized. To address the growth-enhancing potential of candHPV87, the E6 and E7 putative coding regions were cloned and expressed in tissue cultures. The data indicate that both proteins stimulate cell division in tissue cultures more than those of low-risk HPVs, though not as much as those of HPV16. Taken together, the clinical, molecular, and biological data suggest that the novel papillomavirus characterized in the present study is a low- to intermediate-risk HPV.

本研究在妇科中心接诊的受检患者样本中，利用靶向HPV保守L1区域的通用引物，检测到6种疑似新型人乳头瘤病毒（human papillomavirus, HPV）型别。其中1株分离株源自4例宫颈细胞学检查显示挖空细胞异型性的患者样本，其中3例同时感染了1型人类免疫缺陷病毒（human immunodeficiency virus type 1, HIV-1）。该分离株已完成全基因组测序，被鉴定为新型HPV基因型，经人乳头瘤病毒参考中心命名为候选HPV87（candidate HPV87, candHPV87）。candHPV87具备经典的HPV基因组组织结构，且缺失功能性E5编码区。系统发育分析显示，candHPV87基因组聚类于HPV的A3组，与已完成全基因组测序的HPV61、HPV72、HPV83、HPV84及候选HPV86（candHPV86），以及本研究中部分得到鉴定的其他多种疑似新型基因型（其中2种已在本文中描述）同属一簇。为探究candHPV87的促生长潜能，研究人员将其E6及E7候选编码区克隆并在组织培养体系中进行表达。实验数据表明，相较于低危型HPV的对应蛋白，这两种蛋白均可更显著地促进组织培养细胞的增殖，但效果弱于HPV16的对应蛋白。综合临床、分子生物学及生物学实验数据，本研究鉴定的新型乳头瘤病毒属于低危至中危型HPV。