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Vol. 1, No. 3, 2009
Issue release date: April 2009
J Innate Immun 2009;1:202–214
(DOI:10.1159/000203645)

M1 Protein Allows Group A Streptococcal Survival in Phagocyte Extracellular Traps through Cathelicidin Inhibition

Lauth X.a, f · von Köckritz-Blickwede M.a · McNamara C.W.b · Myskowski S.a · Zinkernagel A.S.a · Beall B.e · Ghosh P.b · Gallo R.L.a, c, f · Nizet V.a, d, g
Departments of aPediatrics, bChemistry and Biochemistry, and cMedicine, and dSkaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, Calif., eRespiratory Diseases Branch, Division of Bacterial Diseases, Centers for Disease Control and Prevention, Atlanta, Ga., fVeterans Affairs San Diego Healthcare Center and gRady Children’s Hospital, San Diego, Calif., USA
email Corresponding Author

Abstract

M1 protein contributes to Group A Streptococcus (GAS) systemic virulence by interfering with phagocytosis and through proinflammatory activities when released from the cell surface. Here we identify a novel role of M1 protein in the stimulation of neutrophil and mast cell extracellular trap formation, yet also subsequent survival of the pathogen within these DNA-based innate defense structures. Targeted mutagenesis and heterologous expression studies demonstrate M1 protein promotes resistance to the human cathelicidin antimicrobial peptide LL-37, an important effector of bacterial killing within such phagocyte extracellular traps. Studies with purified recombinant protein fragments mapped the inhibition of cathelicidin killing to the M1 hypervariable N-terminal domain. A survey of GAS clinical isolates found that strains from patients with necrotizing fasciitis or toxic shock syndrome were significantly more likely to be resistant to cathelicidin than GAS M types not associated with invasive disease; M1 isolates were uniformly resistant. We conclude increased resistance to host cathelicidin and killing within phagocyte extracellular traps contribute to the propensity of M1 GAS strains to produce invasive infections.


 goto top of outline Key Words

  • Group A Streptococcus
  • Streptococcus pyogenes
  • Virulence factor
  • Innate immunity
  • M protein
  • Neutrophil
  • Mast cell
  • Extracellular traps
  • Antimicrobial peptide
  • Cathelicidin

 goto top of outline Abstract

M1 protein contributes to Group A Streptococcus (GAS) systemic virulence by interfering with phagocytosis and through proinflammatory activities when released from the cell surface. Here we identify a novel role of M1 protein in the stimulation of neutrophil and mast cell extracellular trap formation, yet also subsequent survival of the pathogen within these DNA-based innate defense structures. Targeted mutagenesis and heterologous expression studies demonstrate M1 protein promotes resistance to the human cathelicidin antimicrobial peptide LL-37, an important effector of bacterial killing within such phagocyte extracellular traps. Studies with purified recombinant protein fragments mapped the inhibition of cathelicidin killing to the M1 hypervariable N-terminal domain. A survey of GAS clinical isolates found that strains from patients with necrotizing fasciitis or toxic shock syndrome were significantly more likely to be resistant to cathelicidin than GAS M types not associated with invasive disease; M1 isolates were uniformly resistant. We conclude increased resistance to host cathelicidin and killing within phagocyte extracellular traps contribute to the propensity of M1 GAS strains to produce invasive infections.

Copyright © 2009 S. Karger AG, Basel


 goto top of outline References
  1. Aziz RK, Kotb M: Rise and persistence of global M1T1 clone of Streptococcus pyogenes. Emerg Infect Dis 2008;14:1511–1517.
  2. O’Grady KA, Kelpie L, Andrews RM, Curtis N, Nolan TM, Selvaraj G, Passmore JW, Oppedisano F, Carnie JA, Carapetis JR: The epidemiology of invasive group A streptococcal disease in Victoria, Australia. Med J Aust 2007;186:565–569.
  3. Darenberg J, Luca-Harari B, Jasir A, Sandgren A, Pettersson H, Schalen C, Norgren M, Romanus V, Norrby-Teglund A, Normark BH: Molecular and clinical characteristics of invasive group A streptococcal infection in Sweden. Clin Infect Dis 2007;45:450–458.
  4. O’Loughlin RE, Roberson A, Cieslak PR, Lynfield R, Gershman K, Craig A, Albanese BA, Farley MM, Barrett NL, Spina NL, Beall B, Harrison LH, Reingold A, Van Beneden C: The epidemiology of invasive group A streptococcal infection and potential vaccine implications: United States, 2000–2004. Clin Infect Dis 2007;45:853–862.
  5. Vlaminckx BJ, Mascini EM, Schellekens JF: Invasive Lancefield group A streptococcal infections in the Netherlands. Ned Tijdschr Geneeskd 2007;151:1669–1673.
  6. Luca-Harari B, Ekelund K, van der Linden M, Staum-Kaltoft M, Hammerum AM, Jasir A: Clinical and epidemiological aspects of invasive Streptococcus pyogenes infections in Denmark during 2003 and 2004. J Clin Microbiol 2008;46:79–86.
  7. Johnson DR, Kaplan EL, VanGheem A, Facklam RR, Beall B: Characterization of group A streptococci (Streptococcus pyogenes): correlation of M-protein and emm-gene type with T-protein agglutination pattern and serum opacity factor. J Med Microbiol 2006;55:157–164.
  8. Cue D, Lam H, Cleary PP: Genetic dissection of the Streptococcus pyogenes M1 protein: regions involved in fibronectin binding and intracellular invasion. Microb Pathog 2001;31:231–242.
  9. Frick IM, Schmidtchen A, Sjobring U: Interactions between M proteins of Streptococcuspyogenes and glycosaminoglycans promote bacterial adhesion to host cells. Eur J Biochem 2003;270:2303–2311.
  10. Berkower C, Ravins M, Moses AE, Hanski E: Expression of different group A streptococcal M proteins in an isogenic background demonstrates diversity in adherence to and invasion of eukaryotic cells. Mol Microbiol 1999;31:1463–1475.
  11. Purushothaman SS, Wang B, Cleary PP: M1 protein triggers a phosphoinositide cascade for group A Streptococcus invasion of epithelial cells. Infect Immun 2003;71:5823–5830.
  12. Bisno AL, Brito MO, Collins CM: Molecular basis of group A streptococcal virulence. Lancet Infect Dis 2003;3:191–200.
  13. Herwald H, Cramer H, Morgelin M, Russell W, Sollenberg U, Norrby-Teglund A, Flodgaard H, Lindbom L, Bjorck L: M protein, a classical bacterial virulence determinant, forms complexes with fibrinogen that induce vascular leakage. Cell 2004;116:367–379.
  14. McNamara C, Zinkernagel AS, Macheboeuf P, Cunningham MW, Nizet V, Ghosh P: Coiled-coil irregularities and instabilities in group A Streptococcus M1 are required for virulence. Science 2008;319:1405–1408.
  15. Brinkmann V, Reichard U, Goosmann C, Fauler B, Uhlemann Y, Weiss DS, Weinrauch Y, Zychlinsky A: Neutrophil extracellular traps kill bacteria. Science 2004;303:1532–1535.
  16. Fuchs TA, Abed U, Goosmann C, Hurwitz R, Schulze I, Wahn V, Weinrauch Y, Brinkmann V, Zychlinsky A: Novel cell death program leads to neutrophil extracellular traps. J Cell Biol 2007;176:231–241.
  17. Brinkmann V, Zychlinsky A: Beneficial suicide: why neutrophils die to make NETs. Nat Rev Microbiol 2007;5:577–582.
  18. Wartha F, Beiter K, Normark S, Henriques-Normark B: Neutrophil extracellular traps: casting the net over pathogenesis. Curr Opin Microbiol 2007;10:52–56.
  19. von Kockritz-Blickwede M, Goldmann O, Thulin P, Heinemann K, Norrby-Teglund A, Rohde M, Medina E: Phagocytosis-independent antimicrobial activity of mast cells by means of extracellular trap formation. Blood 2008;111:3070–3080.
  20. Yousefi S, Gold JA, Andina N, Lee JJ, Kelly AM, Kozlowski E, Schmid I, Straumann A, Reichenbach J, Gleich GJ, Simon HU: Catapult-like release of mitochondrial DNA by eosinophils contributes to antibacterial defense. Nat Med 2008;14:949–953.
  21. Kansal RG, McGeer A, Low DE, Norrby-Teglund A, Kotb M: Inverse relation between disease severity and expression of the streptococcal cysteine protease, SpeB, among clonal M1T1 isolates recovered from invasive group A streptococcal infection cases. Infect Immun 2000;68:6362–6369.
  22. Simon D, Ferretti JJ: Electrotransformation of Streptococcus pyogenes with plasmid and linear DNA. FEMS Microbiol Lett 1991;66:219–224.
  23. Framson PE, Nittayajarn A, Merry J, Youngman P, Rubens CE: New genetic techniques for group B streptococci: high-efficiency transformation, maintenance of temperature-sensitive pwv01 plasmids, and mutagenesis with Tn917. Appl Environ Microbiol 1997;63:3539–3547.
  24. Jeng A, Sakota V, Li Z, Datta V, Beall B, Nizet V: Molecular genetic analysis of a group A Streptococcus operon encoding serum opacity factor and a novel fibronectin-binding protein, SfbX. J Bacteriol 2003;185:1208–1217.
  25. Zaiou M, Nizet V, Gallo RL: Antimicrobial and protease inhibitory functions of the human cathelicidin (hCAP18/LL-37) prosequence. J Invest Dermatol 2003;120:810–816.
  26. Buchanan JT, Simpson AJ, Aziz RK, Liu GY, Kristian SA, Kotb M, Feramisco J, Nizet V: DNAse expression allows the pathogen group a Streptococcus to escape killing in neutrophil extracellular traps. Curr Biol 2006;16:396–400.
  27. Nizet V, Ohtake T, Lauth X, Trowbridge J, Rudisill J, Dorschner RA, Pestonjamasp V, Piraino J, Huttner K, Gallo RL: Innate antimicrobial peptide protects the skin from invasive bacterial infection. Nature 2001;414:454–457.
  28. Braff MH, Zaiou M, Fierer J, Nizet V, Gallo RL: Keratinocyte production of cathelicidin provides direct activity against bacterial skin pathogens. Infect Immun 2005;73:6771–6781.
  29. Di Nardo A, Yamasaki K, Dorschner RA, Lai Y, Gallo RL: Mast cell cathelicidin antimicrobial peptide prevents invasive group A Streptococcus infection of the skin. J Immunol 2008;180:7565–7573.
  30. Kraus D, Peschel A: Molecular mechanisms of bacterial resistance to antimicrobial peptides. Curr Top Microbiol Immunol 2006;306:231–250.
  31. Kristian SA, Datta V, Weidenmaier C, Kansal R, Fedtke I, Peschel A, Gallo RL, Nizet V: D-alanylation of teichoic acids promotes group A Streptococcus antimicrobial peptide resistance, neutrophil survival, and epithelial cell invasion. J Bacteriol 2005;187:6719–6725.
  32. Wartha F, Beiter K, Albiger B, Fernebro J, Zychlinsky A, Normark S, Henriques-Normark B: Capsule and D-alanylated lipoteichoic acids protect Streptococcus pneumoniae against neutrophil extracellular traps. Cell Microbiol 2007;9:1162–1171.
  33. Braff MH, Jones AL, Skerrett SJ, Rubens CE: Staphylococcus aureus exploits cathelicidin antimicrobial peptides produced during early pneumonia to promote staphylokinase-dependent fibrinolysis. J Infect Dis 2007;195:1365–1372.
  34. Frick IM, Akesson P, Rasmussen M, Schmidtchen A, Bjorck L: SIC, a secreted protein of Streptococcus pyogenes that inactivates antibacterial peptides. J Biol Chem 2003;278:16561–16566.
  35. Pahlman LI, Olin AI, Darenberg J, Morgelin M, Kotb M, Herwald H, Norrby-Teglund A: Soluble M1 protein of Streptococcus pyogenes triggers potent T cell activation. Cell Microbiol 2008;10:404–414.
  36. Soehnlein O, Oehmcke S, Ma X, Rothfuchs AG, Frithiof R, van Rooijen N, Morgelin M, Herwald H, Lindbom L: Neutrophil degranulation mediates severe lung damage triggered by streptococcal M1 protein. Eur Respir J 2008;32:405–412.
  37. Kahn F, Morgelin M, Shannon O, Norrby-Teglund A, Herwald H, Olin AI, Bjorck L: Antibodies against a surface protein of Streptococcus pyogenes promote a pathological inflammatory response. PLoS Pathog 2008;4:e1000149.
  38. Perez-Casal J, Okada N, Caparon MG, Scott JR: Role of the conserved C-repeat region of the M protein of Streptococcus pyogenes. Mol Microbiol 1995;15:907–916.
  39. Carlsson F, Berggard K, Stalhammar-Carlemalm M, Lindahl G: Evasion of phagocytosis through cooperation between two ligand-binding regions in Streptococcus pyogenes M protein. J Exp Med 2003;198:1057–1068.
  40. Akesson P, Schmidt KH, Cooney J, Bjorck L: M1 protein and protein H: IgGFc- and albumin-binding streptococcal surface proteins encoded by adjacent genes. Biochem J 1994;300:877–886.
  41. Nilsson M, Wasylik S, Morgelin M, Olin AI, Meijers JC, Derksen RH, de Groot PG, Herwald H: The antibacterial activity of peptides derived from human β-2 glycoprotein I is inhibited by protein H and M1 protein from Streptococcus pyogenes. Mol Microbiol 2008;67:482–492.
  42. Walker MJ, Hollands A, Sanderson-Smith ML, Cole JN, Kirk JK, Henningham A, McArthur JD, Dinkla K, Aziz RK, Kansal RG, Simpson AJ, Buchanan JT, Chhatwal GS, Kotb M, Nizet V: DNAse Sda1 provides selection pressure for a switch to invasive group a streptococcal infection. Nat Med 2007;13:981–985.
  43. Zinkernagel AS, Timmer AM, Pence MA, Locke JB, Buchanan JT, Turner CE, Mishalian I, Sriskandan S, Hanski E, Nizet V: The IL-8 protease SpyCep/ScpC of group A Streptococcus promotes resistance to neutrophil killing. Cell Host Microbe 2008;4:170–178.
  44. Staali L, Morgelin M, Bjorck L, Tapper H: Streptococcus pyogenes expressing M and M-like surface proteins are phagocytosed but survive inside human neutrophils. Cell Microbiol 2003;5:253–265.
  45. Staali L, Bauer S, Morgelin M, Bjorck L, Tapper H: Streptococcus pyogenes bacteria modulate membrane traffic in human neutrophils and selectively inhibit azurophilic granule fusion with phagosomes. Cell Microbiol 2006;8:690–703.
  46. Borregaard N, Sorensen OE, Theilgaard-Monch K: Neutrophil granules: a library of innate immunity proteins. Trends Immunol 2007;28:340–345.
  47. Peschel A, Collins LV: Staphylococcal resistance to antimicrobial peptides of mammalian and bacterial origin. Peptides 2001;22:1651–1659.
  48. Poyart C, Pellegrini E, Marceau M, Baptista M, Jaubert F, Lamy MC, Trieu-Cuot P: Attenuated virulence of Streptococcus agalactiae deficient in D-alanyl-lipoteichoic acid is due to an increased susceptibility to defensins and phagocytic cells. Mol Microbiol 2003;49:1615–1625.
  49. Maisey HC, Quach D, Hensler ME, Liu GY, Gallo RL, Nizet V, Doran KS: A group B streptococcal pilus protein promotes phagocyte resistance and systemic virulence. FASEB J 2008;22:1715–1724.
  50. Schmidtchen A, Frick IM, Andersson E, Tapper H, Bjorck L: Proteinases of common pathogenic bacteria degrade and inactivate the antibacterial peptide LL-37. Mol Microbiol 2002;46:157–168.
  51. Johansson L, Thulin P, Sendi P, Hertzen E, Linder A, Akesson P, Low DE, Agerberth B, Norrby-Teglund A: Cathelicidin LL-37 in severe Streptococcus pyogenes soft tissue infections in humans. Infect Immun 2008;76:3399–3404.
  52. Akesson P, Sjoholm AG, Bjorck L: Protein SIC, a novel extracellular protein of Streptococcus pyogenes interfering with complement function. J Biol Chem 1996;271:1081–1088.
  53. Fernie-King BA, Seilly DJ, Lachmann PJ: The interaction of streptococcal inhibitor of complement (SIC) and its proteolytic fragments with the human beta defensins. Immunology 2004;111:444–452.
  54. Kotb M, Norrby-Teglund A, McGeer A, El-Sherbini H, Dorak MT, Khurshid A, Green K, Peeples J, Wade J, Thomson G, Schwartz B, Low DE: An immunogenetic and molecular basis for differences in outcomes of invasive group a streptococcal infections. Nat Med 2002;8:1398–1404.

 goto top of outline Author Contacts

Prof. Victor Nizet
Department of Pediatrics and Skaggs School of Pharmacy
and Pharmaceutical Sciences, University of California
9500 Gilman Drive, MC 0687, La Jolla, CA 92093-0687 (USA)
Tel. +1 858 534 7408, Fax +1 858 534 5611, E-Mail vnizet@ucsd.edu


 goto top of outline Article Information

X.L. and M.v.K.-B. contributed equally to this manuscript.

Received: November 27, 2008
Accepted after revision: December 15, 2008
Published online: February 20, 2009
Number of Print Pages : 13
Number of Figures : 5, Number of Tables : 0, Number of References : 54
Additional supplemental material is available online.


 goto top of outline Publication Details

Journal of Innate Immunity

Vol. 1, No. 3, Year 2009 (Cover Date: April 2009)

Journal Editor: Herwald H. (Lund), Egesten A. (Lund)
ISSN: 1662-811X (Print), eISSN: 1662-8128 (Online)

For additional information: http://www.karger.com/JIN


Copyright / Drug Dosage / Disclaimer

Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher or, in the case of photocopying, direct payment of a specified fee to the Copyright Clearance Center.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in goverment regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.

Abstract

M1 protein contributes to Group A Streptococcus (GAS) systemic virulence by interfering with phagocytosis and through proinflammatory activities when released from the cell surface. Here we identify a novel role of M1 protein in the stimulation of neutrophil and mast cell extracellular trap formation, yet also subsequent survival of the pathogen within these DNA-based innate defense structures. Targeted mutagenesis and heterologous expression studies demonstrate M1 protein promotes resistance to the human cathelicidin antimicrobial peptide LL-37, an important effector of bacterial killing within such phagocyte extracellular traps. Studies with purified recombinant protein fragments mapped the inhibition of cathelicidin killing to the M1 hypervariable N-terminal domain. A survey of GAS clinical isolates found that strains from patients with necrotizing fasciitis or toxic shock syndrome were significantly more likely to be resistant to cathelicidin than GAS M types not associated with invasive disease; M1 isolates were uniformly resistant. We conclude increased resistance to host cathelicidin and killing within phagocyte extracellular traps contribute to the propensity of M1 GAS strains to produce invasive infections.



 goto top of outline Author Contacts

Prof. Victor Nizet
Department of Pediatrics and Skaggs School of Pharmacy
and Pharmaceutical Sciences, University of California
9500 Gilman Drive, MC 0687, La Jolla, CA 92093-0687 (USA)
Tel. +1 858 534 7408, Fax +1 858 534 5611, E-Mail vnizet@ucsd.edu


 goto top of outline Article Information

X.L. and M.v.K.-B. contributed equally to this manuscript.

Received: November 27, 2008
Accepted after revision: December 15, 2008
Published online: February 20, 2009
Number of Print Pages : 13
Number of Figures : 5, Number of Tables : 0, Number of References : 54
Additional supplemental material is available online.


 goto top of outline Publication Details

Journal of Innate Immunity

Vol. 1, No. 3, Year 2009 (Cover Date: April 2009)

Journal Editor: Herwald H. (Lund), Egesten A. (Lund)
ISSN: 1662-811X (Print), eISSN: 1662-8128 (Online)

For additional information: http://www.karger.com/JIN


Copyright / Drug Dosage

Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher or, in the case of photocopying, direct payment of a specified fee to the Copyright Clearance Center.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in goverment regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.

References

  1. Aziz RK, Kotb M: Rise and persistence of global M1T1 clone of Streptococcus pyogenes. Emerg Infect Dis 2008;14:1511–1517.
  2. O’Grady KA, Kelpie L, Andrews RM, Curtis N, Nolan TM, Selvaraj G, Passmore JW, Oppedisano F, Carnie JA, Carapetis JR: The epidemiology of invasive group A streptococcal disease in Victoria, Australia. Med J Aust 2007;186:565–569.
  3. Darenberg J, Luca-Harari B, Jasir A, Sandgren A, Pettersson H, Schalen C, Norgren M, Romanus V, Norrby-Teglund A, Normark BH: Molecular and clinical characteristics of invasive group A streptococcal infection in Sweden. Clin Infect Dis 2007;45:450–458.
  4. O’Loughlin RE, Roberson A, Cieslak PR, Lynfield R, Gershman K, Craig A, Albanese BA, Farley MM, Barrett NL, Spina NL, Beall B, Harrison LH, Reingold A, Van Beneden C: The epidemiology of invasive group A streptococcal infection and potential vaccine implications: United States, 2000–2004. Clin Infect Dis 2007;45:853–862.
  5. Vlaminckx BJ, Mascini EM, Schellekens JF: Invasive Lancefield group A streptococcal infections in the Netherlands. Ned Tijdschr Geneeskd 2007;151:1669–1673.
  6. Luca-Harari B, Ekelund K, van der Linden M, Staum-Kaltoft M, Hammerum AM, Jasir A: Clinical and epidemiological aspects of invasive Streptococcus pyogenes infections in Denmark during 2003 and 2004. J Clin Microbiol 2008;46:79–86.
  7. Johnson DR, Kaplan EL, VanGheem A, Facklam RR, Beall B: Characterization of group A streptococci (Streptococcus pyogenes): correlation of M-protein and emm-gene type with T-protein agglutination pattern and serum opacity factor. J Med Microbiol 2006;55:157–164.
  8. Cue D, Lam H, Cleary PP: Genetic dissection of the Streptococcus pyogenes M1 protein: regions involved in fibronectin binding and intracellular invasion. Microb Pathog 2001;31:231–242.
  9. Frick IM, Schmidtchen A, Sjobring U: Interactions between M proteins of Streptococcuspyogenes and glycosaminoglycans promote bacterial adhesion to host cells. Eur J Biochem 2003;270:2303–2311.
  10. Berkower C, Ravins M, Moses AE, Hanski E: Expression of different group A streptococcal M proteins in an isogenic background demonstrates diversity in adherence to and invasion of eukaryotic cells. Mol Microbiol 1999;31:1463–1475.
  11. Purushothaman SS, Wang B, Cleary PP: M1 protein triggers a phosphoinositide cascade for group A Streptococcus invasion of epithelial cells. Infect Immun 2003;71:5823–5830.
  12. Bisno AL, Brito MO, Collins CM: Molecular basis of group A streptococcal virulence. Lancet Infect Dis 2003;3:191–200.
  13. Herwald H, Cramer H, Morgelin M, Russell W, Sollenberg U, Norrby-Teglund A, Flodgaard H, Lindbom L, Bjorck L: M protein, a classical bacterial virulence determinant, forms complexes with fibrinogen that induce vascular leakage. Cell 2004;116:367–379.
  14. McNamara C, Zinkernagel AS, Macheboeuf P, Cunningham MW, Nizet V, Ghosh P: Coiled-coil irregularities and instabilities in group A Streptococcus M1 are required for virulence. Science 2008;319:1405–1408.
  15. Brinkmann V, Reichard U, Goosmann C, Fauler B, Uhlemann Y, Weiss DS, Weinrauch Y, Zychlinsky A: Neutrophil extracellular traps kill bacteria. Science 2004;303:1532–1535.
  16. Fuchs TA, Abed U, Goosmann C, Hurwitz R, Schulze I, Wahn V, Weinrauch Y, Brinkmann V, Zychlinsky A: Novel cell death program leads to neutrophil extracellular traps. J Cell Biol 2007;176:231–241.
  17. Brinkmann V, Zychlinsky A: Beneficial suicide: why neutrophils die to make NETs. Nat Rev Microbiol 2007;5:577–582.
  18. Wartha F, Beiter K, Normark S, Henriques-Normark B: Neutrophil extracellular traps: casting the net over pathogenesis. Curr Opin Microbiol 2007;10:52–56.
  19. von Kockritz-Blickwede M, Goldmann O, Thulin P, Heinemann K, Norrby-Teglund A, Rohde M, Medina E: Phagocytosis-independent antimicrobial activity of mast cells by means of extracellular trap formation. Blood 2008;111:3070–3080.
  20. Yousefi S, Gold JA, Andina N, Lee JJ, Kelly AM, Kozlowski E, Schmid I, Straumann A, Reichenbach J, Gleich GJ, Simon HU: Catapult-like release of mitochondrial DNA by eosinophils contributes to antibacterial defense. Nat Med 2008;14:949–953.
  21. Kansal RG, McGeer A, Low DE, Norrby-Teglund A, Kotb M: Inverse relation between disease severity and expression of the streptococcal cysteine protease, SpeB, among clonal M1T1 isolates recovered from invasive group A streptococcal infection cases. Infect Immun 2000;68:6362–6369.
  22. Simon D, Ferretti JJ: Electrotransformation of Streptococcus pyogenes with plasmid and linear DNA. FEMS Microbiol Lett 1991;66:219–224.
  23. Framson PE, Nittayajarn A, Merry J, Youngman P, Rubens CE: New genetic techniques for group B streptococci: high-efficiency transformation, maintenance of temperature-sensitive pwv01 plasmids, and mutagenesis with Tn917. Appl Environ Microbiol 1997;63:3539–3547.
  24. Jeng A, Sakota V, Li Z, Datta V, Beall B, Nizet V: Molecular genetic analysis of a group A Streptococcus operon encoding serum opacity factor and a novel fibronectin-binding protein, SfbX. J Bacteriol 2003;185:1208–1217.
  25. Zaiou M, Nizet V, Gallo RL: Antimicrobial and protease inhibitory functions of the human cathelicidin (hCAP18/LL-37) prosequence. J Invest Dermatol 2003;120:810–816.
  26. Buchanan JT, Simpson AJ, Aziz RK, Liu GY, Kristian SA, Kotb M, Feramisco J, Nizet V: DNAse expression allows the pathogen group a Streptococcus to escape killing in neutrophil extracellular traps. Curr Biol 2006;16:396–400.
  27. Nizet V, Ohtake T, Lauth X, Trowbridge J, Rudisill J, Dorschner RA, Pestonjamasp V, Piraino J, Huttner K, Gallo RL: Innate antimicrobial peptide protects the skin from invasive bacterial infection. Nature 2001;414:454–457.
  28. Braff MH, Zaiou M, Fierer J, Nizet V, Gallo RL: Keratinocyte production of cathelicidin provides direct activity against bacterial skin pathogens. Infect Immun 2005;73:6771–6781.
  29. Di Nardo A, Yamasaki K, Dorschner RA, Lai Y, Gallo RL: Mast cell cathelicidin antimicrobial peptide prevents invasive group A Streptococcus infection of the skin. J Immunol 2008;180:7565–7573.
  30. Kraus D, Peschel A: Molecular mechanisms of bacterial resistance to antimicrobial peptides. Curr Top Microbiol Immunol 2006;306:231–250.
  31. Kristian SA, Datta V, Weidenmaier C, Kansal R, Fedtke I, Peschel A, Gallo RL, Nizet V: D-alanylation of teichoic acids promotes group A Streptococcus antimicrobial peptide resistance, neutrophil survival, and epithelial cell invasion. J Bacteriol 2005;187:6719–6725.
  32. Wartha F, Beiter K, Albiger B, Fernebro J, Zychlinsky A, Normark S, Henriques-Normark B: Capsule and D-alanylated lipoteichoic acids protect Streptococcus pneumoniae against neutrophil extracellular traps. Cell Microbiol 2007;9:1162–1171.
  33. Braff MH, Jones AL, Skerrett SJ, Rubens CE: Staphylococcus aureus exploits cathelicidin antimicrobial peptides produced during early pneumonia to promote staphylokinase-dependent fibrinolysis. J Infect Dis 2007;195:1365–1372.
  34. Frick IM, Akesson P, Rasmussen M, Schmidtchen A, Bjorck L: SIC, a secreted protein of Streptococcus pyogenes that inactivates antibacterial peptides. J Biol Chem 2003;278:16561–16566.
  35. Pahlman LI, Olin AI, Darenberg J, Morgelin M, Kotb M, Herwald H, Norrby-Teglund A: Soluble M1 protein of Streptococcus pyogenes triggers potent T cell activation. Cell Microbiol 2008;10:404–414.
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