Human papillomavirus type 16 (HPV-16) is the predominant genotype worldwide associated with invasive cervical cancer and hence remains as the focus for diagnostic development and vaccine research. L2, the minor capsid protein forms the packaging unit for the HPV genome along with the L1 protein and is primarily associated with transport of genomic DNA to the nucleus. Unlike L1, L2 is known to elicit cross-neutralizing antibodies and thus becomes a suitable candidate for pan-HPV prophylactic vaccine development. In the present study, a total of 148 cervical HPV-16 isolates from Indian women were analyzed by PCR-directed sequencing, phylogenetic analysis and in silico immunoinformatics tools to determine the L2 variations that may impact the immune response and oncogenesis. Ninety-one SNPs translating to 35 non-synonymous amino acid substitutions were observed, of these 16 substitutions are reported in the Indian isolates for the first time. T245A, L266F, S378V and S384A substitutions were significantly associated with high-grade cervical neoplastic status. Multiple substitutions were observed in samples from high-grade cervical neoplastic status as compared to those from normal cervical status (p = 0.027), specifically from the D3 sub-lineage. It was observed that substitution T85A was part of both, B and T cell epitopes recognized by MHC-I molecules; T245A was common to B and T cell epitopes recognized by MHC-II molecules and S122P/A was common to the region recognized by both MHC-I and MHC-II molecules. These findings reporting L2 protein substitutions have implications on cervical oncogenesis and design of next-generation L2-based HPV vaccines.

人乳头瘤病毒 16 型 (HPV-16) 是世界范围内与浸润性宫颈癌相关的主要基因型，因此仍然是诊断开发和疫苗研究的焦点。L2 是一种次要衣壳蛋白，与 L1 蛋白一起形成 HPV 基因组的包装单元，主要与基因组 DNA 向细胞核的转运有关。与 L1 不同，L2 已知可引发交叉中和抗体，因此成为泛 HPV 预防性疫苗开发的合适候选者。在本研究中，通过 PCR 指导测序、系统发育分析和计算机免疫信息学工具对来自印度女性的总共 148 例宫颈 HPV-16 分离株进行了分析，以确定可能影响免疫反应和肿瘤发生的 L2 变异。观察到 91 个 SNP 转化为 35 个非同义氨基酸取代，其中 16 个取代是首次在印度分离株中报道。T245A、L266F、S378V​​ 和 S384A 替换与高级别宫颈肿瘤状态显着相关。与正常宫颈状态的样本相比，在高级别宫颈肿瘤状态的样本中观察到多重替代（p  = 0.027），特别是来自 D3 亚谱系的样本。据观察，T85A 取代是 MHC-I 分子识别的 B 细胞和 T 细胞表位的一部分；T245A 是 MHC-II 分子识别的 B 和 T 细胞表位共有的，S122P/A 是 MHC-I 和 MHC-II 分子识别的区域共有的。这些报告 L2 蛋白替代的发现对宫颈肿瘤发生和下一代基于 L2 的 HPV 疫苗的设计具有影响。