title: Herpes simplex virus type 1 enters human epidermal keratinocytes, but not neurons, via a pH-dependent endocytic pathway.
abstract: Herpes simplex virus (HSV) enters some laboratory cell lines via a pH-dependent, endocytic mechanism. We investigated whether this entry pathway is used in human cell types relevant to pathogenesis. Three different classes of lysosomotropic agents, which raise endosomal pH, blocked HSV entry into primary and transformed human keratinocytes, but not into human neurons or neuroblastoma lines. In keratinocytes, incoming HSV particles colocalized with markers of endocytic uptake. Treatment with the isoflavone genistein, an inhibitor of protein tyrosine kinases, reduced the delivery of incoming viral particles to the nuclear periphery and virus-induced gene expression in keratinocytes but not neurons. Moreover, in keratinocyte monolayer islets, HSV infected both the inner and outer cells in a genistein-sensitive manner, suggesting viral endocytosis from both basolateral and apical plasma membrane surfaces. Together, the results indicate that HSV enters human epidermal keratinocytes, but not neurons, by a low-pH, endocytic pathway that is dependent on host tyrosine phosphorylation. Thus, HSV utilizes fundamentally different cellular entry pathways to infect important target cell populations.
authors.affiliation: Medical Virology Section, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-1888, USA. anicola@niaid.nih.gov
authors.forename: Anthony V
authors.initials: AV
authors.lastname: Nicola
authors.forename: Jean
authors.initials: J
authors.lastname: Hou
authors.forename: Eugene O
authors.initials: EO
authors.lastname: Major
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Straus
mesh_terms: D000818:Animals; D002460:Cell Line; D004705:Endocytosis; D000078404:Epidermal Cells; D004817:Epidermis / Q000821:virology; D019833:Genistein / Q000494:pharmacology; D018259:Herpesvirus 1, Human / Q000472:pathogenicity*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015603:Keratinocytes / Q000821:virology*; D009474:Neurons / Q000821:virology*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D014771:Virion / Q000378:metabolism
chemical_list: D019833:Genistein; D011505:Protein-Tyrosine Kinases