title: Epstein-Barr virus transcytosis through polarized oral epithelial cells.
abstract: Although Epstein-Barr virus (EBV) is an orally transmitted virus, viral transmission through the oropharyngeal mucosal epithelium is not well understood. In this study, we investigated how EBV traverses polarized human oral epithelial cells without causing productive infection. We found that EBV may be transcytosed through oral epithelial cells bidirectionally, from both the apical to the basolateral membranes and the basolateral to the apical membranes. Apical to basolateral EBV transcytosis was substantially reduced by amiloride, an inhibitor of macropinocytosis. Electron microscopy showed that virions were surrounded by apical surface protrusions and that virus was present in subapical vesicles. Inactivation of signaling molecules critical for macropinocytosis, including phosphatidylinositol 3-kinases, myosin light-chain kinase, Ras-related C3 botulinum toxin substrate 1, p21-activated kinase 1, ADP-ribosylation factor 6, and cell division control protein 42 homolog, led to significant reduction in EBV apical to basolateral transcytosis. In contrast, basolateral to apical EBV transcytosis was substantially reduced by nystatin, an inhibitor of caveolin-mediated virus entry. Caveolae were detected in the basolateral membranes of polarized human oral epithelial cells, and virions were detected in caveosome-like endosomes. Methyl β-cyclodextrin, an inhibitor of caveola formation, reduced EBV basolateral entry. EBV virions transcytosed in either direction were able to infect B lymphocytes. Together, these data show that EBV transmigrates across oral epithelial cells by (i) apical to basolateral transcytosis, potentially contributing to initial EBV penetration that leads to systemic infection, and (ii) basolateral to apical transcytosis, which may enable EBV secretion into saliva in EBV-infected individuals.
authors.affiliation: Department of Medicine, University of California San Francisco, San Francisco, California, USA. sharof.tugizov@ucsf.edu
authors.forename: Sharof M
authors.initials: SM
authors.lastname: Tugizov
authors.forename: Rossana
authors.initials: R
authors.lastname: Herrera
authors.forename: Joel M
authors.initials: JM
authors.lastname: Palefsky
mesh_terms: D000089982:ADP-Ribosylation Factor 6; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D002144:Callithrix; D002460:Cell Line; D017931:DNA Primers / Q000235:genetics; D005455:Fluorescent Antibody Technique; D004854:Herpesvirus 4, Human / Q000472:pathogenicity / Q000502:physiology*; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D015603:Keratinocytes / Q000821:virology; D046529:Microscopy, Electron, Transmission; D009061:Mouth Mucosa / Q000821:virology*; D009761:Nystatin / Q000494:pharmacology; D014066:Palatine Tonsil / Q000166:cytology; D016133:Polymerase Chain Reaction; D034741:RNA, Small Interfering / Q000235:genetics; D015398:Signal Transduction / Q000502:physiology; D057900:Transcytosis / Q000187:drug effects / Q000502:physiology*; D022161:Transport Vesicles / Q000648:ultrastructure / Q000821:virology; D014771:Virion / Q000502:physiology / Q000648:ultrastructure
chemical_list: D000089982:ADP-Ribosylation Factor 6; D017931:DNA Primers; D007074:Immunoglobulin G; D034741:RNA, Small Interfering; D009761:Nystatin; D000584:Amiloride; C000715348:ARF6 protein, human