Complement-mediated opsonization of invasive group A Streptococcus pyogenes strain AP53 is regulated by the bacterial two-component cluster of virulence responder/sensor (CovRS) system.
Group A Streptococcus pyogenes (GAS) strain AP53 is a primary isolate from a patient with necrotizing fasciitis. These AP53 cells contain an inactivating mutation in the sensor component of the cluster of virulence (cov) responder (R)/sensor (S) two-component gene regulatory system (covRS), which enhances the virulence of the primary strain, AP53/covR(+)S(-). However, specific mechanisms by which the covRS system regulates the survival of GAS in humans are incomplete. Here, we show a key role for covRS in the regulation of opsonophagocytosis of AP53 by human neutrophils. AP53/covR(+)S(-) cells displayed potent binding of host complement inhibitors of C3 convertase, viz. Factor H (FH) and C4-binding protein (C4BP), which concomitantly led to minimal C3b deposition on AP53 cells, further showing that these plasma protein inhibitors are active on GAS cells. This resulted in weak killing of the bacteria by human neutrophils and a corresponding high death rate of mice after injection of these cells. After targeted allelic alteration of covS(-) to wild-type covS (covS(+)), a dramatic loss of FH and C4BP binding to the AP53/covR(+)S(+) cells was observed. This resulted in elevated C3b deposition on AP53/covR(+)S(+) cells, a high level of opsonophagocytosis by human neutrophils, and a very low death rate of mice infected with AP53/covR(+)S(+). We show that covRS is a critical transcriptional regulator of genes directing AP53 killing by neutrophils and regulates the levels of the receptors for FH and C4BP, which we identify as the products of the fba and enn genes, respectively.
W. M. Keck Center for Transgene Research; Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556.
Garima
G
Agrahari
W. M. Keck Center for Transgene Research.
Zhong
Z
Liang
W. M. Keck Center for Transgene Research.
Jeffrey A
JA
Mayfield
W. M. Keck Center for Transgene Research; Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556.
Rashna D
RD
Balsara
W. M. Keck Center for Transgene Research; Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556.
Victoria A
VA
Ploplis
W. M. Keck Center for Transgene Research; Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556. Electronic address: fcastell@nd.edu.
Francis J
FJ
Castellino
D000818:Animals; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics; D003179:Complement C3b / Q000235:genetics / Q000378:metabolism; D050716:Complement C4b-Binding Protein / Q000235:genetics / Q000378:metabolism; D017242:Complement Factor H / Q000235:genetics / Q000378:metabolism; D005260:Female; D005634:Fructose-Bisphosphate Aldolase; D000071677:Histidine Kinase; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D009504:Neutrophils / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D010587:Phagocytosis; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D013290:Streptococcal Infections / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D013297:Streptococcus pyogenes / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; C055609:C4BPA protein, human; D002352:Carrier Proteins; D050716:Complement C4b-Binding Protein; C432143:CsrR protein, Streptococcus pyogenes; C088686:Enn protein, Streptococcus pyogenes; C445329:Fba protein, Streptococcus pyogenes; D047908:Intracellular Signaling Peptides and Proteins; D012097:Repressor Proteins; D037521:Virulence Factors; D003179:Complement C3b; D017242:Complement Factor H; C534547:CovS protein, Streptococcus pyogenes; D000071677:Histidine Kinase; D005634:Fructose-Bisphosphate Aldolase
Bacteria; Bacterial Genetics; Bacterial Transcription; Gene Regulation; Gene Transcription; Streptococcus pyogenes; Transcription Regulation; Transcription Target Genes