Lack of molecular mimicry between HPV vaccine L1 antigen and human proteins by a computational analysis

Background Although human papillomavirus (HPV) vaccines are effective in preventing cervical cancer, the HPV vaccination rate in Japan is low due to concerns about alleged neurological adverse events, which were proposed in the ongoing HPV vaccine lawsuits. Based on the molecular mimicry theory by Darja Kanduc, plaintiffs' attorneys argued that HPV vaccines could cause organ damage due to cross-reactive autoantibodies. Kauduc proposed a flawed hypothesis that molecular mimicry would induce cross-reactive antibodies even when only the portions of amino acid (AA)-sequences of the epitopes were identical between microbial and human proteins. Methods In this study, we conducted the same computational data analysis as Kanduc, using 22 linear epitopes (9–23 AA-length) of the HPV type 16 L1 protein (HPV16L1) registered in the database. Results We found that no human epitopes had identical AA-sequences to any HPV16L1 epitopes, demonstrating that HPV16L1 had no molecular mimicry with linear epitopes that have the potential to induce cross-reactive autoantibodies. On the other hand, we identified various numbers of human protein epitopes whose AA-sequences were partially identical with epitopes of HPV16L1, hepatitis B virus (HBV), and syncytial virus (RSV). We found that HPV16L1 had a smaller number of such proteins having “partial molecular mimicry” than HBV and RSV. Conclusions Our current in silico analysis provided no evidence that HPV vaccinations could induce cross-reactive autoantibodies. The flawed molecular mimicry data should not be used as a scientific basis for alleged HPV vaccine-induced adverse events.