Genetic variation of E6, E7, and L1 genes of human papillomavirus 51 from central China

The incidence of cervical cancer is closely related to high-risk human papillomavirus (HR-HPV). Women in Jingzhou had relatively high susceptibility to HPV-51, whose ratio was 9.61% (456/4743) among HR-HPV-positive samples and ranked fifth in all analyzed HR-HPV types. In this study, variations and phylogenetic trees of HPV-51 E6-E7 and L1 sequences were analyzed by MEGA-X. The selective pressure was estimated using PAML. The B-cell epitope of L1 amino acid sequences and T-cell epitope of E6 and E7 amino acid sequences were further predicted by ABCpred server and IEDB website, respectively. In the E6-E7 sequences 14 single nucleotide variants occurred, among which 4 were nonsynonymous variants and 10 were synonymous variants. A total of 41 single nucleotide variants were identified in the L1 sequences, including 10 nonsynonymous variants and 31 synonymous variants. All the isolates of both E6-E7 and L1 were classified into the A variant lineage. In HPV-51 E6-E7 and L1 sequences, no positively selected site was found. Two nonconservative substitutions, H119Y and N176S in L1, affected multiple hypothetical B-cell epitopes. Three nonconservative substitutions, T86P, S100L in E6, and F29L in E7, affected multiple hypothetical T-cell epitopes. Elucidation of the HR-HPV prevalence characteristics and genetic variations of HPV-51 in central China may contribute to future investigations of diagnostic probes, therapeutic or preventative vaccines with wider coverage.