Genetic Variation of HPV53 and the Identification of T-Cell Epitopes.

Human papillomavirus type 53 (HPV53) is one of the most prevalent HPV genotypes in China, frequently detected in cervical intraepithelial neoplasia and cervical cancer, yet remains outside the coverage of all currently available prophylactic vaccines and is relatively understudied. This study performed a comprehensive analysis of HPV53 clinical infection profiles, genomic diversity, and T-cell epitopes to inform therapeutic vaccine development. Clinical analysis of 158 HPV53-positive patients showed that infections were most prevalent in women aged 40-59 years, with persistent infection identified in 13.3% participants and a subset of cases associated with cervical lesions. Genomic analysis of 134 HPV53 isolates identified four lineages (A-D, with lineage D further subdivided into four sublineages, and an overall nucleotide variability of 4.4%. E2 was the most variable protein while E7 was the most conserved. Immunoinformatic prediction identified 176 HLA class I-restricted T-cell epitopes across E6, E7, E1, and E2, from which 20 candidates were selected for experimental validation. Ten demonstrated strong HLA binding affinity in vitro, and murine immunization identified a E6 peptide VYNFAYTDL as an immunodominant epitope. Three validated epitopes exhibited sequence overlap with 12 to 13 of other 13 high-risk HPV genotypes, suggesting their potential as broadly cross-reactive targets. These findings clarify the genomic diversity and immunogenic epitope landscape of HPV53, providing a foundation for the rational design of therapeutic vaccines.