Sequence of myosin-crossreactive epitopes of streptococcal M protein.

Group A streptococcal M proteins contain epitopes that crossreact with sarcolemmal membrane proteins of human myocardium and myosin. In the present study, synthetic peptide copies spanning the entire 197-residue pepsin extracted fragment of type 5 M protein were used to localize the myosin-crossreactive epitopes of the molecule. Peptide 84-116 inhibited by 75% the binding of myosin-crossreactive antibodies evoked by pep M5, as determined by ELISA. Immunoblot inhibition studies confirmed that peptide 84-116 almost totally inhibited the binding of pep M5 antibodies to the heavy chain of human cardiac myosin. None of the remaining synthetic peptides, including peptide 1-35, which contains protective epitopes, inhibited antibodies binding to myosin. Two of three rabbits immunized with peptide 84-116 developed low but significant levels of antibodies crossreactive with myosin. Identification of the primary structures containing tissue-crossreactive as opposed to protective epitopes should not only allow the development of safe and effective M protein vaccines, but may also provide insights into the pathogenesis of rheumatic heart disease.

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Protective and heart-crossreactive epitopes located within the NH2 terminus of type 19 streptococcal M protein.

Journal of Experimental Medicine ◽

10.1084/jem.167.6.1849 ◽

1988 ◽

Vol 167 (6) ◽

pp. 1849-1859 ◽

Cited By ~ 31

Author(s):

M S Bronze ◽

E H Beachey ◽

J B Dale

Keyword(s):

Amino Acids ◽

Heart Disease ◽

Primary Structure ◽

Synthetic Peptide ◽

Human Myocardium ◽

M Protein ◽

Streptococcal M Protein ◽

M Proteins ◽

Rheumatic Heart

M protein was purified to homogeneity from limited pepsin digests of intact type 19 streptococci (pep M19). The purified pep M19 when emulsified in CFA and injected into rabbits evoked type-specific and crossreactive opsonic antibodies, as well as heart-crossreactive antibodies. The NH2-terminal primary structure of pep M19 was determined and a peptide copying the first 24 amino acids [SM19(1-24)C] was chemically synthesized. Rabbits that were immunized with the unconjugated peptide developed antibodies that recognized the native pep M19, as determined by ELISA, and opsonic antibodies against type 19 streptococci, as determined by in vitro opsonophagocytosis tests. The synthetic peptide also evoked antibodies that crossreacted with a 60-kD sarcolemmal membrane protein of human myocardium. By using overlapping synthetic subpeptides as immunoinhibitors, the opsonic and heart-crossreactive epitopes of SM19(1-24)C were localized to SM19(11-24)C. Our data confirm the presence of heart-crossreactive epitopes within the primary structure of pep M19 and show that these potentially harmful autoimmune epitopes may be located in the NH2-terminal regions of certain M proteins. We conclude that continued efforts to identify the primary structures of protective and heart-crossreactive epitopes will be necessary to elucidate the pathogenesis of acute rheumatic heart disease and to develop safe and effective streptococcal vaccines.

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B- and T-Cell Responses in Group A Streptococcus M-Protein- or Peptide-Induced Experimental Carditis

Infection and Immunity ◽

10.1128/iai.01514-08 ◽

2009 ◽

Vol 77 (5) ◽

pp. 2177-2183 ◽

Cited By ~ 30

Author(s):

Davina Gorton ◽

Brenda Govan ◽

Colleen Olive ◽

Natkunam Ketheesan

Keyword(s):

Molecular Mimicry ◽

Group A Streptococcus ◽

M Protein ◽

Cardiac Myosin ◽

Additional Information ◽

Cell Responses ◽

Valve Tissue ◽

Group A ◽

Valvular Lesions ◽

Rheumatic Heart

ABSTRACT The etiology of rheumatic fever and rheumatic heart disease (RF/RHD) is believed to be autoimmune, involving immune responses initiated between streptococcal and host tissue proteins through a molecular mimicry mechanism(s). We sought to investigate the humoral and cellular responses elicited in a Lewis rat model of group A streptococcus M-protein- or peptide-induced experimental valvulitis/carditis, a recently developed animal model which may, in part, represent human rheumatic carditis. Recombinant streptococcal M5 protein elicited opsonic antibodies in Lewis rats, and anti-M5 antisera recognized epitopes within the B- and C-repeat regions of M5. One peptide from the streptococcal M5 protein B-repeat region (M5-B.6, amino acids 161 to 180) induced lymphocytes that responded to both recombinant M5 and cardiac myosin. Rats immunized with streptococcal M5 protein developed valvular lesions, distinguished by infiltration of CD3+, CD4+, and CD68+ cells into valve tissue, consistent with human studies that suggest that RF/RHD are mediated by inflammatory CD4+ T cells and CD68+ macrophages. The current study provides additional information that supports the use of the rat autoimmune valvulitis model for investigating RF/RHD.

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Multiple, heart-cross-reactive epitopes of streptococcal M proteins.

Journal of Experimental Medicine ◽

10.1084/jem.161.1.113 ◽

1985 ◽

Vol 161 (1) ◽

pp. 113-122 ◽

Cited By ~ 95

Author(s):

J B Dale ◽

E H Beachey

Keyword(s):

Membrane Proteins ◽

Heart Tissue ◽

Human Myocardium ◽

M Protein ◽

Antigenic Determinants ◽

Serotype Distribution ◽

Present Evidence ◽

Sarcolemmal Membrane ◽

Streptococcal M Protein ◽

M Proteins

We present evidence that a highly purified pepsin extract of type 5 streptococcal M protein (pep M5) contains at least three epitopes that are cross-reactive with sarcolemmal membrane proteins of human myocardium. The tissue-cross-reactive determinants of pep M5 are also partially shared with pep M6 and pep M19. Three rabbits immunized with a single 300 micrograms dose of pep M5 developed significant levels of heart-cross-reactive antibodies, as determined by indirect immunofluorescence tests. All three sera also contained antibodies that cross-reacted with pep M6 and pep M19. The heart tissue--specific antibodies that were eluted from sarcolemmal membranes opsonized types 5, 6, and 19 streptococci, indicating that they were directed against protective M protein epitopes on the surface of virulent organisms. Immunofluorescence inhibition tests, using purified M proteins as soluble inhibitors of heart-cross-reactive antibodies, revealed the number and M protein serotype distribution of the tissue-cross-reactive epitopes. Immunoblot analyses demonstrated the sarcolemmal membrane proteins containing the various cross-reactive antigenic determinants.

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T-cell mimicry of streptococcal M protein and cardiac myosin epitopes by T-cell clones from rheumatic heart disease

International Congress Series ◽

10.1016/j.ics.2005.12.003 ◽

2006 ◽

Vol 1289 ◽

pp. 296-299

Author(s):

Nadia M.J. Ellis ◽

Ya Li ◽

William Hildebrand ◽

Vincent A. Fischetti ◽

Madeleine W. Cunningham

Keyword(s):

Heart Disease ◽

T Cell ◽

Rheumatic Heart Disease ◽

M Protein ◽

Cardiac Myosin ◽

T Cell Clones ◽

Streptococcal M Protein ◽

Cell Clones ◽

Rheumatic Heart

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Reactivity of Rheumatic Fever and Scarlet Fever Patients' Sera with Group A Streptococcal M Protein, Cardiac Myosin, and Cardiac Tropomyosin: a Retrospective Study

Infection and Immunity ◽

10.1128/iai.68.12.7132-7136.2000 ◽

2000 ◽

Vol 68 (12) ◽

pp. 7132-7136 ◽

Cited By ~ 11

Author(s):

Kevin F. Jones ◽

Stephen S. Whitehead ◽

Madeleine W. Cunningham ◽

Vincent A. Fischetti

Keyword(s):

Retrospective Study ◽

Rheumatic Fever ◽

Scarlet Fever ◽

Acute Rheumatic Fever ◽

M Protein ◽

Group A Streptococci ◽

Cardiac Myosin ◽

Streptococcal M Protein ◽

Group A ◽

Low Levels

ABSTRACT Archived sera (collected in 1946) from acute rheumatic fever (ARF) and untreated scarlet fever and/or pharyngitis patients were reacted with streptococcal M protein, cardiac myosin, and cardiac tropomyosin. Except for very low levels to tropomyosin, antibodies to other antigens were not elevated in the sera of ARF patients relative to those of non-ARF patients, even though there was roughly equivalent exposure to group A streptococci. This suggests that antibodies to these molecules may not play a central role in the induction of ARF.

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Epitopes of streptococcal M proteins shared with cardiac myosin.

Journal of Experimental Medicine ◽

10.1084/jem.162.2.583 ◽

1985 ◽

Vol 162 (2) ◽

pp. 583-591 ◽

Cited By ~ 140

Author(s):

J B Dale ◽

E H Beachey

Keyword(s):

Acute Rheumatic Fever ◽

M Protein ◽

Light Chains ◽

Myosin Light Chains ◽

Myosin Heavy Chains ◽

Cardiac Myosin ◽

Poststreptococcal Glomerulonephritis ◽

Heavy Chains ◽

M Proteins ◽

Group A

We present evidence that M proteins from three different serotypes of group A streptococci share epitopes with cardiac myosin. Rabbit antisera evoked by a purified fragment of type 5 M protein crossreacted with myosin, but not alpha-tropomyosin, actin, or myosin light chains. In enzyme-linked immunosorbent assays, the myosin-crossreactive antibodies were totally inhibited by type 5 M protein and partially inhibited by types 6 and 19 M proteins. The affinity-purified myosin antibodies opsonized type 5 streptococci, indicating that they were directed against protective M protein epitopes on the surface of the organisms. Immunoblot analyses demonstrated the binding of the crossreactive antibodies to myosin heavy chains. Sera from patients with acute rheumatic fever showed significantly stronger reactions with myosin than did sera from their siblings, hospitalized controls, or patients with poststreptococcal glomerulonephritis.

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Repeat exposure to group A streptococcal M protein exacerbates cardiac damage in a rat model of rheumatic heart disease

Autoimmunity ◽

10.1080/08916934.2016.1217999 ◽

2016 ◽

Vol 49 (8) ◽

pp. 563-570 ◽

Cited By ~ 10

Author(s):

Davina Gorton ◽

Suchandan Sikder ◽

Natasha L. Williams ◽

Lisa Chilton ◽

Catherine M. Rush ◽

...

Keyword(s):

Heart Disease ◽

Rheumatic Heart Disease ◽

Rat Model ◽

M Protein ◽

Cardiac Damage ◽

Streptococcal M Protein ◽

Repeat Exposure ◽

Group A ◽

Rheumatic Heart

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The Plasminogen-Binding Group A Streptococcal M Protein-Related Protein Prp Binds Plasminogen via Arginine and Histidine Residues

Journal of Bacteriology ◽

10.1128/jb.01218-06 ◽

2006 ◽

Vol 189 (4) ◽

pp. 1435-1440 ◽

Cited By ~ 48

Author(s):

Martina L. Sanderson-Smith ◽

Mark Dowton ◽

Marie Ranson ◽

Mark J. Walker

Keyword(s):

Binding Site ◽

Group A Streptococcus ◽

Invasive Disease ◽

Site Directed Mutagenesis ◽

M Protein ◽

Histidine Residues ◽

Streptococcal M Protein ◽

M Proteins ◽

Lysine Residues ◽

Group A

ABSTRACT The migration of the human pathogen Streptococcus pyogenes (group A streptococcus) from localized to deep tissue sites may result in severe invasive disease, and sequestration of the host zymogen plasminogen appears crucial for virulence. Here, we describe a novel plasminogen-binding M protein, the plasminogen-binding group A streptococcal M protein (PAM)-related protein (Prp). Prp is phylogenetically distinct from previously described plasminogen-binding M proteins of group A, C, and G streptococci. While competition experiments indicate that Prp binds plasminogen with a lower affinity than PAM (50% effective concentration = 0.34 μM), Prp nonetheless binds plasminogen with high affinity and at physiologically relevant concentrations of plasminogen (Kd = 7.8 nM). Site-directed mutagenesis of the putative plasminogen binding site indicates that unlike the majority of plasminogen receptors, Prp does not interact with plasminogen exclusively via lysine residues. Mutagenesis to alanine of lysine residues Lys96 and Lys101 reduced but did not abrogate plasminogen binding by Prp. Plasminogen binding was abolished only with the additional mutagenesis of Arg107 and His108 to alanine. Furthermore, mutagenesis of Arg107 and His108 abolished plasminogen binding by Prp despite the presence of Lys96 and Lys101 in the binding site. Thus, binding to plasminogen via arginine and histidine residues appears to be a conserved mechanism among plasminogen-binding M proteins.

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Superantigenicity of streptococcal M protein.

Journal of Experimental Medicine ◽

10.1084/jem.172.1.359 ◽

1990 ◽

Vol 172 (1) ◽

pp. 359-362 ◽

Cited By ~ 96

Author(s):

M Tomai ◽

M Kotb ◽

G Majumdar ◽

E H Beachey

Keyword(s):

T Cells ◽

Mhc Class Ii ◽

Class Ii ◽

M Protein ◽

Streptococcal M Protein ◽

Human T Cells ◽

M Proteins ◽

Group A ◽

Cell Mitogen ◽

Antigen Presenting

M proteins that define the serotypes of group A streptococci are powerful blastogens for human T lymphocytes. The mechanism by which they activate T cells was investigated and compared with the conventional T cell mitogen phytohemagglutinin, and the known superantigen staphylococcal enterotoxin B. Although major histocompatibility complex (MHC) class II molecules are required for presentation, there is no MHC restriction, since allogeneic class II molecules presented the bacterial protein to human T cells. Type 5 M protein appears to bind class II molecules on the antigen-presenting cells and stimulate T cells bearing V beta 8 sequences. Our results indicate that this streptococcal M protein is a superantigen and suggest a possible mechanism of its role in the pathogenesis of the postinfectious autoimmune sequelae.

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