title: Modification of the hemagglutinin cleavage site allows indirect activation of avian influenza virus H9N2 by bacterial staphylokinase.
abstract: Influenza H9N2 is considered to be a low pathogenicity avian influenza (LPAI) virus that commonly infects avian species and can also infect humans. In 1996, the influenza virus, A/chicken/Korea/MS96-CE6/1996/H9N2 (MS96) was isolated from an outbreak in multiple farms in South Korea that resulted in upwards of 30% mortality in infected chickens, with the virus infecting a number of extrapulmonary tissues, indicating internal spread. However, in experimental infections, complete recovery of specific pathogen free (SPF) chickens occurred. Such a discrepancy indicated an alternative pathway for MS96 virus to gain virulence in farmed chickens. A key determinant of influenza pathogenesis is the susceptibility of the viral hemagglutinin (HA) to proteolytic cleavage/activation. Here, we identified that an amino acid substitution, Ser to Tyr found at the P2 position of the MS96 HA cleavage site optimizes cleavage by the protease plasmin (Pm). Importantly, we identified that certain Staphylococcus sp. are able to cleave and activate MS96 HA by activating plasminogen (Plg) to plasmin by use of a virulence factor, staphylokinase. Overall, these studies provide an in-vitro mechanism for bacterially mediated enhancement of influenza activation, and allow insight into the microbiological mechanisms underlying the avian influenza H9N2 outbreak in Korea in1996.
authors.affiliation: Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, C4127 VMC Ithaca NY 14853, United States; New York Center of Excellence for Influenza Research and Surveillance, University of Rochester Medical Center, Rochester NY 14627, United States.
authors.forename: Longping V
authors.initials: LV
authors.lastname: Tse
authors.affiliation: Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, C4127 VMC Ithaca NY 14853, United States; New York Center of Excellence for Influenza Research and Surveillance, University of Rochester Medical Center, Rochester NY 14627, United States. Electronic address: grw7@cornell.edu.
authors.forename: Gary R
authors.initials: GR
authors.lastname: Whittaker
mesh_terms: D000818:Animals; D002645:Chickens; D004196:Disease Outbreaks; D005341:Fibrinolysin / Q000378:metabolism; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics / Q000378:metabolism*; D053127:Influenza A Virus, H9N2 Subtype / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D005585:Influenza in Birds / Q000453:epidemiology / Q000821:virology*; D007723:Korea; D008666:Metalloendopeptidases / Q000378:metabolism*; D056265:Microbial Interactions; D020125:Mutation, Missense; D014774:Virulence
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus; D005341:Fibrinolysin; D008666:Metalloendopeptidases; C022653:auR protein, Staphylococcus aureus
keywords: Avian influenza; Bacterial co-infection; Hemagglutinin; Influenza virus; Plasmin; Protease
references.citation: Nat Rev Immunol. 2012 Apr;12(4):295-305
references.pmid: 22402670
references.citation: PLoS Pathog. 2013 Feb;9(2):e1003151
references.pmid: 23459660
references.citation: J Infect Dis. 1992 Oct;166(4):783-91
references.pmid: 1527412
references.citation: J Virol. 2000 Jul;74(13):6015-20
references.pmid: 10846083
references.citation: J Infect Dis. 2003 Mar 15;187(6):1000-9
references.pmid: 12660947
references.citation: Avian Dis. 2000 Jul-Sep;44(3):527-35
references.pmid: 11006999
references.citation: J Virol. 2014 May;88(10):5608-16
references.pmid: 24600012
references.citation: J Virol. 2014 Feb;88(3):1673-83
references.pmid: 24257604
references.citation: Virology. 1975 Dec;68(2):426-39
references.pmid: 173078
references.citation: PLoS One. 2012;7(4):e35876
references.pmid: 22558251
references.citation: Trends Microbiol. 1994 Feb;2(2):39-43
references.pmid: 8162439
references.citation: Cell Mol Life Sci. 1999 Oct 1;56(1-2):104-32
references.pmid: 11213252
references.citation: J Biol Chem. 1991 Jun 25;266(18):11826-32
references.pmid: 2050679
references.citation: Can J Biochem. 1969 Oct;47(10):927-31
references.pmid: 4981635
references.citation: Trends Microbiol. 1999 Mar;7(3):99-100
references.pmid: 10203834
references.citation: J Clin Pathol. 1981 Sep;34(9):979-81
references.pmid: 7276224
references.citation: J Virol. 1993 Nov;67(11):6667-73
references.pmid: 8411368
references.citation: J Virol. 2013 May;87(9):5161-9
references.pmid: 23449787
references.citation: Virology. 1981 Sep;113(2):725-35
references.pmid: 7023022
references.citation: Chem Biol. 2000 Jun;7(6):443-53
references.pmid: 10873836
references.citation: Nat Biotechnol. 2000 Feb;18(2):187-93
references.pmid: 10657126
references.citation: Cell. 1998 Oct 30;95(3):409-17
references.pmid: 9814710
references.citation: Proc Natl Acad Sci U S A. 1998 Aug 18;95(17):10224-8
references.pmid: 9707628
references.citation: Pathog Dis. 2013 Nov;69(2):87-100
references.pmid: 23821437
references.citation: J Biol Chem. 2013 Jun 14;288(24):17399-407
references.pmid: 23612974
references.citation: JAMA. 2013 Jan 16;309(3):275-82
references.pmid: 23321766
references.citation: J Mol Genet Med. 2009 Jan 16;3(1):152-7
references.pmid: 19565023
references.citation: Nature. 1994 Sep 1;371(6492):37-43
references.pmid: 8072525
references.citation: Trends Microbiol. 2014 Nov;22(11):623-31
references.pmid: 25264312
references.citation: J Virol. 2010 Sep;84(17):8683-90
references.pmid: 20554779
references.citation: J Virol. 2014 May;88(9):4744-51
references.pmid: 24522916
references.citation: J Gen Virol. 1995 Mar;76 ( Pt 3):625-33
references.pmid: 7897352
references.citation: J Virol. 2006 Oct;80(19):9896-8
references.pmid: 16973594
references.citation: J Virol. 1994 Nov;68(11):7537-9
references.pmid: 7933138
references.citation: J Clin Microbiol. 2005 Nov;43(11):5760-7
references.pmid: 16272514
references.citation: Annu Rev Biochem. 2000;69:531-69
references.pmid: 10966468
references.citation: Nature. 1960 Feb 27;185:626
references.pmid: 13814336
references.citation: Nature. 2009 Jun 25;459(7250):1122-5
references.pmid: 19516283
references.citation: Vet Microbiol. 2006 Dec 20;118(3-4):169-76
references.pmid: 16930870
references.citation: Lancet. 1999 Sep 11;354(9182):916-7
references.pmid: 10489954
references.citation: J Biol Chem. 2010 Jul 2;285(27):21153-64
references.pmid: 20435890
references.citation: Biochemistry. 1992 Apr 21;31(15):3852-61
references.pmid: 1314651
references.citation: J Biol Chem. 1972 Mar 25;247(6):1683-91
references.pmid: 4258976
references.citation: Biol Chem. 2012 Sep;393(9):907-14
references.pmid: 22944691
references.citation: Proc Natl Acad Sci U S A. 2000 Aug 15;97(17):9654-8
references.pmid: 10920197
references.citation: J Virol. 2012 Oct;86(19):10579-86
references.pmid: 22811538
references.citation: Virology. 1973 Nov;56(1):172-80
references.pmid: 4795670
references.citation: PLoS Pathog. 2013;9(12):e1003774
references.pmid: 24348248
references.citation: Proc Natl Acad Sci U S A. 1988 Jan;85(2):324-8
references.pmid: 2829180