Ikuo Tsunoda

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

Abstract Background Although human papillomavirus (HPV) vaccines effectively prevent cervical cancer, the HPV vaccination rates in Japan remain low because of concerns about alleged neurological adverse events. Darja Kanduc proposed a flawed hypothesis that molecular mimicry between HPV and human proteins could induce cross-reactive antibodies, causing autoimmune organ damage, even when only the portions of amino acid (AA)-sequences of the epitopes were identical between HPV 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 respiratory 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.

Scientific evaluation of alleged findings in HPV vaccines: Molecular mimicry and mouse models of vaccine‐induced disease

AbstractCervical cancer is caused by infections of the human papillomavirus (HPV), which can be prevented by vaccinations. In Japan, although about 3000 people die of cervical cancer annually, the HPV vaccination rate has remained extremely low in the eligible population since many Japanese have been concerned that “diverse symptoms,” such as chronic pain, movement disorders, and cognitive impairment, may occur as adverse reactions after HPV vaccination. The concern has been raised by media coverage of the ongoing HPV vaccine lawsuits, in which the plaintiffs complained of their symptoms caused by HPV vaccination. The claims have been based on the alleged pathogenic findings in research articles on HPV vaccines, summarized in the document prepared by the plaintiffs' attorneys. We critically evaluated these articles, in which the authors proposed the following findings/hypothesis: (i) molecular mimicry between HPV L1 and human proteins leads to the production of cross‐reactive antibodies; and (ii) HPV vaccine injection in mice causes damage in the brain, a mouse model for HPV vaccine associated neuro‐immunopathic syndrome (HANS). We found that these hypotheses were based mainly on the findings from a few research groups and that all the articles had flaws in the method, result, or discussion sections. Our current evaluation should help better understand the validity of the findings, which have been often misunderstood as the truth by the general public. We propose to accumulate high‐quality data on potential adverse events following HPV vaccination and to continue critically evaluating them.