Toll-like receptor 5 (TLR5) agonist, the recombinant flagellin, has been intensively investigated and optimized as a safe and effective mucosal adjuvant in animal model.23,24 In developing mucosal vaccines for dental caries,25 we observed that the flagellin adjuvanted subunit mucosal vaccines can elicit enduring antibodies, lasting up to 13 months in mice (Supplementary Fig. 1). The gene discussed is TLR5; the disease is dental caries.