Intratype variants and high genotypic diversity of human papillomavirus with polymorphisms in the antigenic hypervariable loops of the L1 protein from women living with human immunodeficiency virus in Northeastern Brazil.

The human papillomavirus (HPV) is one of the main oncogenic viruses. High-risk HPV types are associated with the development of cervical cancers. In addition, it is known that some mutations in HPV genes, or variant viral lineages, have been associated with greater oncogenic risk. The L1 protein is the major component of the viral capsid and is therefore used in currently available vaccines. However, the characterization of mutations in the L1 gene, which is relevant to increasing the knowledge of the immune escape mechanisms used by the virus, is still incipient. This study aimed to characterize mutations associated with antigenic domains in the L1 protein of HPVs isolated from cervical samples of women living with HIV in Northeastern Brazil. L1 gene sequences were obtained from the samples, and the mutations and the viral variants were characterized. Phylogenetic and functional analyses of the structure of the L1 protein were carried out. A total of 41 HPV variant isolates were obtained, distributed among 16 different viral types. Of this, 25 non-synonymous mutations were evaluated regarding the stability of the L1 protein. It was observed that 10 of these mutations were predicted to increase, and 14 to decrease, the stability of the L1 protein and that most of them occurred in the FG hypervariable antigenic loop. These results add useful knowledge to understanding the biological and immunological aspects of HPV variants and the impact of these mutations on the development of vaccine strategies.