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Abstract
M and M-like proteins are major virulence factors of the widespread and potentially deadly bacterial pathogen Streptococcus pyogenes. These proteins confer resistance against innate and adaptive immune responses by recruiting specific human proteins to the streptococcal surface. Nonimmune recruitment of immunoglobulins G (IgG) and A (IgA) through their fragment crystallizable (Fc) domains by M and M-like proteins was described almost 40 years ago, but its impact on virulence remains unresolved. These interactions have been suggested to be consequential under immune conditions at mucosal surfaces and in secretions but not in plasma, while other evidence suggests importance in evading phagocytic killing in nonimmune blood. Recently, an indirect effect of Fc-binding through ligand-induced stabilization of an M-like protein was shown to increase virulence. Nonimmune recruitment has also been seen to contribute to tissue damage in animal models of autoimmune diseases triggered by S. pyogenes infection. The damage was treatable by targeting Fc-binding. This and other potential therapeutic applications warrant renewed attention to Fc-binding by M and M-like proteins.
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Affiliation(s)
- Jori O. Mills
- Department of Chemistry & Biochemistry, La Jolla, California, United States of America
| | - Partho Ghosh
- Department of Chemistry & Biochemistry, La Jolla, California, United States of America
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2
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Ermert D, Weckel A, Magda M, Mörgelin M, Shaughnessy J, Rice PA, Björck L, Ram S, Blom AM. Human IgG Increases Virulence of Streptococcus pyogenes through Complement Evasion. THE JOURNAL OF IMMUNOLOGY 2018; 200:3495-3505. [PMID: 29626087 DOI: 10.4049/jimmunol.1800090] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 03/12/2018] [Indexed: 12/21/2022]
Abstract
Streptococcus pyogenes is an exclusively human pathogen that can provoke mild skin and throat infections but can also cause fatal septicemia. This gram-positive bacterium has developed several strategies to evade the human immune system, enabling S. pyogenes to survive in the host. These strategies include recruiting several human plasma proteins, such as the complement inhibitor, C4b-binding protein (C4BP), and human (hu)-IgG through its Fc region to the bacterial surface to evade immune recognition. We identified a novel virulence mechanism whereby IgG-enhanced binding of C4BP to five of 12 tested S. pyogenes strains expressed diverse M proteins that are important surface-expressed virulence factors. Importantly, all strains that bound C4BP in the absence of IgG bound more C4BP when IgG was present. Further studies with an M1 strain that additionally expressed protein H, also a member of the M protein family, revealed that binding of hu-IgG Fc to protein H increased the affinity of protein H for C4BP. Increased C4BP binding accentuated complement downregulation, resulting in diminished bacterial killing. Accordingly, mortality from S. pyogenes infection in hu-C4BP transgenic mice was increased when hu-IgG or its Fc portion alone was administered concomitantly. Electron microscopy analysis of human tissue samples with necrotizing fasciitis confirmed increased C4BP binding to S. pyogenes when IgG was present. Our findings provide evidence of a paradoxical function of hu-IgG bound through Fc to diverse S. pyogenes isolates that increases their virulence and may counteract the beneficial effects of IgG opsonization.
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Affiliation(s)
- David Ermert
- Division of Medical Protein Chemistry, Department of Translational Medicine, Lund University, 214 28 Malmo, Sweden; .,Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605; and
| | - Antonin Weckel
- Division of Medical Protein Chemistry, Department of Translational Medicine, Lund University, 214 28 Malmo, Sweden
| | - Michal Magda
- Division of Medical Protein Chemistry, Department of Translational Medicine, Lund University, 214 28 Malmo, Sweden
| | - Matthias Mörgelin
- Division of Infection Medicine, Department of Clinical Sciences, Lund University, 221 84 Lund, Sweden
| | - Jutamas Shaughnessy
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605; and
| | - Peter A Rice
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605; and
| | - Lars Björck
- Division of Infection Medicine, Department of Clinical Sciences, Lund University, 221 84 Lund, Sweden
| | - Sanjay Ram
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605; and
| | - Anna M Blom
- Division of Medical Protein Chemistry, Department of Translational Medicine, Lund University, 214 28 Malmo, Sweden
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3
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Abstract
Proteins capable of non-immune binding of immunoglobulins G (IgG) of various mammalian species, i.e. without the involvement of the antigen-binding sites of the immunoglobulins, are widespread in bacteria. These proteins are located on the surface of bacterial cells and help them to evade the host's immune response due to protection against the action of complement and to decrease in phagocytosis. This review summarizes data on the structure of immunoglobulin-binding proteins (IBP) and their complexes with IgG. Common and distinctive structural features of IBPs of gram-positive bacteria (staphylococci, streptococci, peptostreptococci) are discussed. Conditions for IBP expression by bacteria and their functional heterogeneity are considered. Data on IBPs of gram-negative bacteria are presented.
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Affiliation(s)
- E V Sidorin
- Pacific Institute of Bioorganic Chemistry, Far-Eastern Division of the Russian Academy of Sciences, Vladivostok, Russia.
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4
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Smeesters PR, McMillan DJ, Sriprakash KS. The streptococcal M protein: a highly versatile molecule. Trends Microbiol 2010; 18:275-82. [PMID: 20347595 DOI: 10.1016/j.tim.2010.02.007] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Revised: 02/23/2010] [Accepted: 02/25/2010] [Indexed: 11/25/2022]
Abstract
Interaction of the M-protein of group A Streptococcus (GAS) with its numerous host binding partners might assist the bacteria in evading host immune responses. Although the extensive diversity of this protein has been highlighted by different GAS typing schemes, most of the structural and functional information has been obtained from a limited number of types. Increasing numbers of epidemiological, clinical and biological reports suggest that the structure and function of the M protein is less conserved than previously thought. This review focuses on the known interactions between M proteins and host ligand proteins, emphasizing that our understanding of this well-studied molecule is fragmented.
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Affiliation(s)
- Pierre R Smeesters
- Bacterial Pathogenesis Laboratory, Queensland Institute of Medical Research, Brisbane 4029, Queensland, Australia.
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McMillan DJ, Batzloff MR, Browning CL, Davies MR, Good MF, Sriprakash KS, Janulczyk R, Rasmussen M. Identification and assessment of new vaccine candidates for group A streptococcal infections. Vaccine 2004; 22:2783-90. [PMID: 15246612 DOI: 10.1016/j.vaccine.2004.01.043] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2003] [Revised: 12/20/2003] [Accepted: 01/08/2004] [Indexed: 10/26/2022]
Abstract
Group A Streptococcus (GAS) is a human-specific pathogen responsible for a wide variety of human diseases. Numerous GAS surface antigens interact with the human immune system and only some of these proteins have been studied in depth. A few of these may elicit protective response against GAS infection. In this study, we have used an in silico approach to identify antigenic peptides from GAS surface proteins. Putative GAS surface proteins from the M1 GAS genome were identified by the presence on LPxTG cell-wall anchoring motif and an export signal sequence. This technique identified 17 proteins of known or putative function, and another 11 which do not have known homologues. Peptides derived from predicted antigenic sequences near the amino terminus of six of these proteins, and another seven peptides derived from the two known surface proteins, GRAB and MtsA, were conjugated to keyhole lymphocyanin (KLH), and investigated for their capacity to induce opsonic antibody responses in outbred Quackenbush mice. All peptide-KLH antisera demonstrated opsonic capacity against both 88/30 and M1 GAS. However, KLH sera alone was also able to induce opsonic antibodies, suggesting that anti-KLH antibodies contributed to the opsonisation seen in the peptide-KLH antisera. KLH is therefore a promising carrier molecule for potential GAS peptide vaccines.
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MESH Headings
- Animals
- Antibodies, Bacterial/analysis
- Antibodies, Bacterial/biosynthesis
- Antigens, Bacterial/chemistry
- Antigens, Bacterial/immunology
- Antigens, Surface/immunology
- Computer Simulation
- DNA Primers
- DNA, Bacterial/genetics
- DNA, Bacterial/immunology
- Drug Design
- Drug Evaluation, Preclinical
- Enzyme-Linked Immunosorbent Assay
- Epitopes/immunology
- Female
- Genes, Bacterial/genetics
- Genes, Bacterial/immunology
- Mice
- Microscopy, Fluorescence
- Open Reading Frames/genetics
- Open Reading Frames/immunology
- Opsonin Proteins/pharmacology
- Peptides/immunology
- Reverse Transcriptase Polymerase Chain Reaction
- Streptococcal Infections/immunology
- Streptococcal Infections/prevention & control
- Streptococcal Vaccines/immunology
- Streptococcus pyogenes/immunology
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Affiliation(s)
- David J McMillan
- Division of Infectious Diseases and Immunology, The Queensland Institute of Medical Research, Brisbane,
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6
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Coleman JL, Benach JL. Use of the plasminogen activation system by microorganisms. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 1999; 134:567-76. [PMID: 10595783 DOI: 10.1016/s0022-2143(99)90095-1] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The use of host-derived PAS components by invasive bacteria is an increasingly recognized mechanism for acquisition of extracellular proteolytic activity. This overview summarizes the pertinent contributions to this field and is divided into three parts: (1) the PAS, (2) the interaction of bacteria that produce their own plasminogen activators with the host's PAS, and (3) the interaction of bacteria that do not produce their own plasminogen activators but use plasminogen activators supplied by the host. The significance of these mechanisms in relation to the invasive potentials of the various organisms is discussed.
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Affiliation(s)
- J L Coleman
- State of New York Department of Health, State University of New York at Stony Brook, 11794-8692, USA
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Navarre WW, Schneewind O. Surface proteins of gram-positive bacteria and mechanisms of their targeting to the cell wall envelope. Microbiol Mol Biol Rev 1999; 63:174-229. [PMID: 10066836 PMCID: PMC98962 DOI: 10.1128/mmbr.63.1.174-229.1999] [Citation(s) in RCA: 925] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cell wall envelope of gram-positive bacteria is a macromolecular, exoskeletal organelle that is assembled and turned over at designated sites. The cell wall also functions as a surface organelle that allows gram-positive pathogens to interact with their environment, in particular the tissues of the infected host. All of these functions require that surface proteins and enzymes be properly targeted to the cell wall envelope. Two basic mechanisms, cell wall sorting and targeting, have been identified. Cell well sorting is the covalent attachment of surface proteins to the peptidoglycan via a C-terminal sorting signal that contains a consensus LPXTG sequence. More than 100 proteins that possess cell wall-sorting signals, including the M proteins of Streptococcus pyogenes, protein A of Staphylococcus aureus, and several internalins of Listeria monocytogenes, have been identified. Cell wall targeting involves the noncovalent attachment of proteins to the cell surface via specialized binding domains. Several of these wall-binding domains appear to interact with secondary wall polymers that are associated with the peptidoglycan, for example teichoic acids and polysaccharides. Proteins that are targeted to the cell surface include muralytic enzymes such as autolysins, lysostaphin, and phage lytic enzymes. Other examples for targeted proteins are the surface S-layer proteins of bacilli and clostridia, as well as virulence factors required for the pathogenesis of L. monocytogenes (internalin B) and Streptococcus pneumoniae (PspA) infections. In this review we describe the mechanisms for both sorting and targeting of proteins to the envelope of gram-positive bacteria and review the functions of known surface proteins.
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Affiliation(s)
- W W Navarre
- Department of Microbiology & Immunology, UCLA School of Medicine, Los Angeles, California 90095, USA
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Pack TD, Boyle MD. Characterization of a type II'o group A streptococcal immunoglobulin-binding protein. Mol Immunol 1995; 32:1235-43. [PMID: 8559148 DOI: 10.1016/0161-5890(95)00074-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The opacity factor positive M type 2 group A streptococcal isolate, A207, expresses a unique functional type II'o IgG-binding protein which reacts with all four human IgG subclasses and rabbit IgG. In order to determine the gene product or products responsible for this activity, three genes of the vir regulon from this isolate were cloned, expressed and analysed. The fcr A2 gene coded for a protein binding hyman IgG1, IgG2 and IgG4 but not IgG3. The enn2 gene coded for a protein reacting exclusively with human IgA, while the emmL2 gene product bound IgG1, IgG2, IgG3 and IgG4 as well as rabbit but not horse or pig IgG. The IgG3-binding activity of the EmmL2 protein was functionally indistinguishable from the Form 1 IgG3-binding activity present in heat extracts of group A isolate A207.
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Affiliation(s)
- T D Pack
- Department of Microbiology, Medical College of Ohio, Toledo 43699-0008, USA
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