scholarly journals Streptococcus Mutans And The Problem of Heart Cross-Reactivity

1990 ◽  
Vol 1 (3) ◽  
pp. 191-205 ◽  
Author(s):  
Michael W. Russell ◽  
Hongyin Wu
Keyword(s):  
Streptococcus Mutans ◽  
Human Heart ◽  
Molecular Mechanisms ◽  
Surface Protein ◽  
Preventive Measure ◽  
Heart Tissue ◽  
Cross Reactivity ◽  
Group A Streptococci ◽  
Group A ◽  
Circulating Antibodies

Investigations of immune responses to Streptococcus mutans have fostered consideration of vaccination as a possible preventive measure against dental caries. However, the finding that hyperimmune rabbit antisera to S. mutans sometimes give immunofluorescent reactions on human heart raised concerns over safety, especially as most individuals display circulating antibodies to this common oral organism. Recent progress in elucidating the molecular mechanisms of the well-established immunological cross-reactivity between group A streptococci and human heart tissue and the structure of S. mutans antigens permits a re-evaluation of this problem. This review examines the evidence for heart cross-reactivity induced by S. mutans in relation to studies on group A streptococci and current understanding of autoimmunity. Although the mechanisms involved in this phenomenon need further clarification, it now appears that it cannot be ascribed to antigenic similarity between heart tissue and a high-molecular-weight surface protein antigen of S. mutans.

scholarly journals Bacterial Immunoglobulin Superantigen Proteins A and L Activate Human Heart Mast Cells by Interacting with Immunoglobulin E

2000 ◽  
Vol 68 (10) ◽  
pp. 5517-5524 ◽  
Author(s):  
Arturo Genovese ◽  
Jean-Pierre Bouvet ◽  
Giovanni Florio ◽  
Bärbel Lamparter-Schummert ◽  
Lars Björck ◽  
...  
Keyword(s):  
Mast Cells ◽  
Human Heart ◽  
Immunoglobulin E ◽  
Protein A ◽  
Surface Protein ◽  
Heart Tissue ◽  
Protein L ◽  
Cysteinyl Leukotriene ◽  
Proinflammatory Mediators

ABSTRACT Human heart mast cells (HHMC) have been identified in heart tissue, perivascularly, and in the intima of coronary arteries. In vitro activation of isolated HHMC induces the release of vasoactive and proinflammatory mediators (histamine, tryptase, and cysteinyl leukotriene C4 [LTC4]). We investigated the effects of several bacterial proteins on HHMC activation in vitro. HHMC released histamine, tryptase, and LTC4 in response toStaphylococcus aureus Cowan 1 and the immunoglobulin (Ig)-binding protein A, but not to S. aureus Wood 46, which does not synthesize protein A. The effect of protein A was inhibited by preincubation with monoclonal IgM VH3+. Some strains of Peptostreptococcus magnus express an Ig light chain-binding surface protein called protein L. Such bacteria and soluble protein L stimulated the release of preformed and newly synthesized mediators from HHMC. Preincubation of HHMC with either protein A or protein L resulted in complete cross-desensitization to a subsequent challenge with the heterologous stimulus or anti-IgE. Monoclonal IgE (κ chains) blocked protein L-induced release, whereas IgE (λ chains) had no effect. Streptococcal protein G, formyl-containing tripeptide, and pepstatin A did not activate HHMC. Bacterial products protein A and protein L and intact bacteria (S. aureus and P. magnus) activate HHMC by acting as Ig superantigens.

Molecular mechanisms of adhesion, colonization, and invasion of group A streptococci

2002 ◽  
Vol 34 (2) ◽  
pp. 77-87 ◽  
Author(s):  
Harry S Courtney ◽  
David L Hasty ◽  
James B Dale
Keyword(s):  
Molecular Mechanisms ◽  
Group A Streptococci ◽  
Group A ◽  
Mechanisms Of Adhesion
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