title: Varicella-Zoster Virus and Herpes Simplex Virus 1 Differentially Modulate NKG2D Ligand Expression during Productive Infection.
abstract: Natural killer (NK) cell-deficient patients are particularly susceptible to severe infection with herpesviruses, especially varicella-zoster virus (VZV) and herpes simplex virus 1 (HSV-1). The critical role that NK cells play in controlling these infections denotes an intricate struggle for dominance between virus and NK cell antiviral immunity; however, research in this area has remained surprisingly limited. Our study addressed this absence of knowledge and found that infection with VZV was not associated with enhanced NK cell activation, suggesting that the virus uses specific mechanisms to limit NK cell activity. Analysis of viral regulation of ligands for NKG2D, a potent activating receptor ubiquitously expressed on NK cells, revealed that VZV differentially modulates expression of the NKG2D ligands MICA, ULBP2, and ULBP3 by upregulating MICA expression while reducing ULBP2 and ULBP3 expression on the surface of infected cells. Despite being closely related to VZV, infection with HSV-1 produced a remarkably different effect on NKG2D ligand expression. A significant decrease in MICA, ULBP2, and ULBP3 was observed with HSV-1 infection at a total cellular protein level, as well as on the cell surface. We also demonstrate that HSV-1 differentially regulates expression of an additional NKG2D ligand, ULBP1, by reducing cell surface expression while total protein levels are unchanged. Our findings illustrate both a striking point of difference between two closely related alphaherpesviruses, as well as suggest a powerful capacity for VZV and HSV-1 to evade antiviral NK cell activity through novel modulation of NKG2D ligand expression.
  
  
  OBJECTIVE
  Patients with deficiencies in NK cell function experience an extreme susceptibility to infection with herpesviruses, in particular, VZV and HSV-1. Despite this striking correlation, research into understanding how these two alphaherpesviruses interact with NK cells is surprisingly limited. Through examination of viral regulation of ligands to the activating NK cell receptor NKG2D, we reveal patterns of modulation by VZV, which were unexpectedly varied in response to regulation by HSV-1 infection. Our study begins to unravel the undoubtedly complex interactions that occur between NK cells and alphaherpesvirus infection by providing novel insights into how VZV and HSV-1 manipulate NKG2D ligand expression to modulate NK cell activity, while also illuminating a distinct variation between two closely related alphaherpesviruses.
authors.affiliation: Discipline of Infectious Diseases and Immunology, Sydney Medical School, Charles Perkins Centre, University of Sydney, Sydney, NSW, Australia.
authors.forename: Tessa M
authors.initials: TM
authors.lastname: Campbell
authors.affiliation: Discipline of Infectious Diseases and Immunology, Sydney Medical School, Charles Perkins Centre, University of Sydney, Sydney, NSW, Australia.
authors.forename: Brian P
authors.initials: BP
authors.lastname: McSharry
authors.affiliation: Discipline of Infectious Diseases and Immunology, Sydney Medical School, Charles Perkins Centre, University of Sydney, Sydney, NSW, Australia.
authors.forename: Megan
authors.initials: M
authors.lastname: Steain
authors.affiliation: Discipline of Infectious Diseases and Immunology, Sydney Medical School, Charles Perkins Centre, University of Sydney, Sydney, NSW, Australia.
authors.forename: Barry
authors.initials: B
authors.lastname: Slobedman
authors.affiliation: Discipline of Infectious Diseases and Immunology, Sydney Medical School, Charles Perkins Centre, University of Sydney, Sydney, NSW, Australia allison.abendroth@sydney.edu.au.
authors.forename: Allison
authors.initials: A
authors.lastname: Abendroth
mesh_terms: D002460:Cell Line; D058851:GPI-Linked Proteins / Q000235:genetics / Q000276:immunology; D006561:Herpes Simplex / Q000235:genetics* / Q000276:immunology / Q000821:virology; D006562:Herpes Zoster / Q000235:genetics* / Q000276:immunology / Q000821:virology; D018259:Herpesvirus 1, Human / Q000235:genetics / Q000502:physiology*; D014645:Herpesvirus 3, Human / Q000235:genetics / Q000502:physiology*; D015395:Histocompatibility Antigens Class I / Q000235:genetics* / Q000276:immunology; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics* / Q000276:immunology; D007694:Killer Cells, Natural / Q000276:immunology; D008024:Ligands; D055655:NK Cell Lectin-Like Receptor Subfamily K / Q000235:genetics* / Q000276:immunology
chemical_list: D058851:GPI-Linked Proteins; D015395:Histocompatibility Antigens Class I; D036341:Intercellular Signaling Peptides and Proteins; C527085:KLRK1 protein, human; D008024:Ligands; C099187:MHC class I-related chain A; D055655:NK Cell Lectin-Like Receptor Subfamily K; C423230:ULBP2 protein, human; C423229:ULBP3 protein, human