title: Synergistic inhibition of human cytomegalovirus replication by interferon-alpha/beta and interferon-gamma.
abstract: BACKGROUND
  Recent studies have shown that gamma interferon (IFN-gamma) synergizes with the innate IFNs (IFN-alpha and IFN-beta) to inhibit herpes simplex virus type 1 (HSV-1) replication in vitro. To determine whether this phenomenon is shared by other herpesviruses, we investigated the effects of IFNs on human cytomegalovirus (HCMV) replication.
  
  
  RESULTS
  We have found that as with HSV-1, IFN-gamma synergizes with the innate IFNs (IFN-alpha/beta) to potently inhibit HCMV replication in vitro. While pre-treatment of human foreskin fibroblasts (HFFs) with IFN-alpha, IFN-beta or IFN-gamma alone inhibited HCMV plaque formation by approximately 30 to 40-fold, treatment with IFN-alpha and IFN-gamma or IFN-beta and IFN-gamma inhibited HCMV plaque formation by 163- and 662-fold, respectively. The generation of isobole plots verified that the observed inhibition of HCMV plaque formation and replication in HFFs by IFN-alpha/beta and IFN-gamma was a synergistic interaction. Additionally, real-time PCR analyses of the HCMV immediate early (IE) genes (IE1 and IE2) revealed that IE mRNA expression was profoundly decreased in cells stimulated with IFN-alpha/beta and IFN-gamma (approximately 5-11-fold) as compared to vehicle-treated cells. Furthermore, decreased IE mRNA expression was accompanied by a decrease in IE protein expression, as demonstrated by western blotting and immunofluorescence.
  
  
  CONCLUSIONS
  These findings suggest that IFN-alpha/beta and IFN-gamma synergistically inhibit HCMV replication through a mechanism that may involve the regulation of IE gene expression. We hypothesize that IFN-gamma produced by activated cells of the adaptive immune response may potentially synergize with endogenous type I IFNs to inhibit HCMV dissemination in vivo.
authors.affiliation: Department of Microbiology and Immunology, Program in Molecular Pathogenesis and Immunity, Tulane University Health Sciences Center, 1430 Tulane Avenue, SL-38, New Orleans, LA 70112, USA. bsainz@scripps.edu
authors.forename: Bruno
authors.initials: B
authors.lastname: Sainz
authors.forename: Heather L
authors.initials: HL
authors.lastname: LaMarca
authors.forename: Robert F
authors.initials: RF
authors.lastname: Garry
authors.forename: Cindy A
authors.initials: CA
authors.lastname: Morris
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology*; D002478:Cells, Cultured; D003587:Cytomegalovirus / Q000187:drug effects* / Q000276:immunology / Q000502:physiology*; D004357:Drug Synergism; D005347:Fibroblasts / Q000648:ultrastructure / Q000821:virology; D015967:Gene Expression Regulation, Viral; D006801:Humans; D016898:Interferon-alpha / Q000276:immunology / Q000494:pharmacology*; D016899:Interferon-beta / Q000276:immunology / Q000494:pharmacology*; D007371:Interferon-gamma / Q000276:immunology / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D010948:Viral Plaque Assay; D014779:Virus Replication / Q000187:drug effects*
chemical_list: D000998:Antiviral Agents; D016898:Interferon-alpha; D012333:RNA, Messenger; D016899:Interferon-beta; D007371:Interferon-gamma
references.citation: Eur Heart J. 1993 Dec;14 Suppl K:30-8
references.pmid: 8131785
references.citation: AIDS. 2003 Nov 21;17(17):2445-50
references.pmid: 14600515
references.citation: Proc Natl Acad Sci U S A. 1996 Oct 15;93(21):11321-6
references.pmid: 8876134
references.citation: J Virol. 1996 Nov;70(11):7569-79
references.pmid: 8892876
references.citation: Microbiol Immunol. 1997;41(5):403-13
references.pmid: 9194039
references.citation: J Virol. 1998 Jan;72(1):366-79
references.pmid: 9420235
references.citation: J Exp Med. 1998 Mar 2;187(5):675-83
references.pmid: 9480977
references.citation: Cancer Res. 1998 Jun 15;58(12):2489-99
references.pmid: 9635566
references.citation: J Biol Chem. 1998 Aug 14;273(33):20737-43
references.pmid: 9694816
references.citation: Proc Natl Acad Sci U S A. 1998 Dec 22;95(26):15623-8
references.pmid: 9861020
references.citation: Virology. 1998 Dec 20;252(2):324-30
references.pmid: 9878611
references.citation: J Immunol. 1999 May 15;162(10):6107-13
references.pmid: 10229853
references.citation: J Immunol. 2002 Sep 15;169(6):3257-66
references.pmid: 12218145
references.citation: Curr Top Microbiol Immunol. 2002;269:153-70
references.pmid: 12224507
references.citation: J Am Soc Nephrol. 2002 Oct;13(10):2577-84
references.pmid: 12239248
references.citation: Nucleic Acids Res. 2001 May 1;29(9):e45
references.pmid: 11328886
references.citation: J Virol. 2002 Nov;76(22):11541-50
references.pmid: 12388715
references.citation: J Virol. 2003 Mar;77(6):3602-14
references.pmid: 12610136
references.citation: J Virol. 2003 Apr;77(8):4588-96
references.pmid: 12663765
references.citation: J Immunol. 2000 Jan 15;164(2):926-33
references.pmid: 10623841
references.citation: J Virol. 2000 Mar;74(5):2477-80
references.pmid: 10666284
references.citation: Virology. 2000 Apr 10;269(2):383-90
references.pmid: 10753717
references.citation: J Virol. 2000 Sep;74(17):8140-50
references.pmid: 10933725
references.citation: J Gen Virol. 2000 Oct;81(Pt 10):2341-64
references.pmid: 10993923
references.citation: Proc Natl Acad Sci U S A. 2000 Oct 24;97(22):12289-94
references.pmid: 11027311
references.citation: Annu Rev Immunol. 2001;19:65-91
references.pmid: 11244031
references.citation: J Paediatr Child Health. 2001 Apr;37(2):187-92
references.pmid: 11328477
references.citation: J Virol. 2001 Aug;75(16):7543-54
references.pmid: 11462026
references.citation: J Gen Virol. 2001 Oct;82(Pt 10):2405-13
references.pmid: 11562534
references.citation: J Virol. 2002 May;76(9):4441-55
references.pmid: 11932411
references.citation: Viral Immunol. 2002;15(1):95-119
references.pmid: 11952150
references.citation: J Infect Dis. 2002 Jul 1;186(1):15-22
references.pmid: 12089657
references.citation: Nat Rev Immunol. 2002 Sep;2(9):675-87
references.pmid: 12209136
references.citation: J Virol. 2004 Jan;78(1):197-205
references.pmid: 14671101
references.citation: Am J Pathol. 2004 Feb;164(2):589-600
references.pmid: 14742264
references.citation: J Virol. 2004 Feb;78(4):1817-30
references.pmid: 14747546
references.citation: J Virol. 2004 Mar;78(6):3162-9
references.pmid: 14990737
references.citation: J Immunol. 2004 May 15;172(10):6107-14
references.pmid: 15128796
references.citation: J Virol. 2004 Aug;78(15):7867-73
references.pmid: 15254159
references.citation: Virology. 2004 Nov 10;329(1):11-7
references.pmid: 15476870
references.citation: J Virol. 1975 Aug;16(2):298-310
references.pmid: 168404
references.citation: J Gen Virol. 1982 Jun;60(Pt 2):261-70
references.pmid: 6180127
references.citation: Transplantation. 1984 Feb;37(2):161-4
references.pmid: 6320509
references.citation: Am J Med. 1984 Mar;76(3):385-92
references.pmid: 6322583
references.citation: Arch Virol. 1987;94(3-4):177-89
references.pmid: 3034207
references.citation: Arch Virol. 1987;94(3-4):323-9
references.pmid: 3034215
references.citation: Pharmacol Rev. 1989 Jun;41(2):93-141
references.pmid: 2692037
references.citation: J Gen Virol. 1991 Sep;72 ( Pt 9):2059-64
references.pmid: 1654370
references.citation: J Interferon Cytokine Res. 2003 May;23(5):247-57
references.pmid: 12804067
references.citation: Nature. 2003 Jul 24;424(6947):456-61
references.pmid: 12879076
references.citation: Proc Natl Acad Sci U S A. 2003 Sep 30;100(20):11439-44
references.pmid: 12972646
references.citation: J Virol. 1995 Sep;69(9):5391-400
references.pmid: 7636984