Existence of SARS-CoV-2 entry molecules in the oral cavity

Wakako Sakaguchi, Nobuhisa Kubota, Tomoko Shimizu, Juri Saruta, Shinya Fuchida, Akira Kawata, Yuko Yamamoto, Masahiro Sugimoto, Mayumi Yakeishi, Keiichi Tsukinoki

Research output: Contribution to journalArticlepeer-review

128 Citations (Scopus)


The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) receptor, angiotensin-converting enzyme 2 (ACE2), transmembrane protease serine 2 (TMPRSS2), and furin, which promote entry of the virus into the host cell, have been identified as determinants of SARS-CoV-2 infection. Dorsal tongue and gingiva, saliva, and tongue coating samples were examined to determine the presence of these molecules in the oral cavity. Immunohistochemical analyses showed that ACE2 was expressed in the stratified squamous epithelium of the dorsal tongue and gingiva. TMPRSS2 was strongly expressed in stratified squamous epithelium in the keratinized surface layer and detected in the saliva and tongue coating samples via Western blot. Furin was localized mainly in the lower layer of stratified squamous epithelium and detected in the saliva but not tongue coating. ACE2, TMPRSS2, and furin mRNA expression was observed in taste bud-derived cultured cells, which was similar to the immunofluorescence observations. These data showed that essential molecules for SARS-CoV-2 infection were abundant in the oral cavity. However, the database analysis showed that saliva also contains many protease inhibitors. Therefore, although the oral cavity may be the entry route for SARS-CoV-2, other factors including protease inhibitors in the saliva that inhibit viral entry should be considered.

Original languageEnglish
Article number6000
Pages (from-to)1-16
Number of pages16
JournalInternational journal of molecular sciences
Issue number17
Publication statusPublished - 2020 Sept 1
Externally publishedYes


  • ACE2
  • Furin
  • Oral cavity
  • SARS-CoV-2
  • Saliva
  • Taste cell
  • Tongue coating

ASJC Scopus subject areas

  • Catalysis
  • Molecular Biology
  • Spectroscopy
  • Computer Science Applications
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry


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