A review of the correlation of T-agglutination patterns and M-protein typing and opacity factor production in the identification of group A streptococci

ABSTRACT Serum opacity factor (SOF) is a protein expressed by Streptococcus pyogenes that opacifies mammalian serum. SOF is also a virulence factor of S. pyogenes, but it has not been previously shown to elicit a protective immune response. Herein, we report that SOF evokes bactericidal antibodies against S. pyogenes in humans, rabbits, and mice. Rabbit antiserum against purified recombinant SOF2 opsonized SOF-positive M type 2, 4, and 28 S. pyogenes in human blood but had no effect on SOF-negative M type 5 S. pyogenes. Furthermore, affinity-purified human antibodies against SOF2 also opsonized SOF-positive streptococci. A combination of antisera against M2 and SOF2 proteins was dramatically more effective in killing streptococci than either antiserum alone, indicating that antibodies against SOF2 enhance the opsonic efficiency of M protein antibodies. Mice tolerated an intravenous injection of 100 μg of SOF without overt signs of toxicity, and immunization with SOF protected mice against challenge infections with M type 2 S. pyogenes. These data indicate that SOF evokes opsonic antibodies that may protect against infections by SOF-positive serotypes of group A streptococci and suggest that different serotypes of SOF have common epitopes that may be useful vaccine candidates to protect against group A streptococcal infections.

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Non-M protein(s) on the cell wall and membrane of group A streptococci induce(s) IFN-γ production by dermal CD4 + T cells in psoriasis

Archives of Dermatological Research ◽

10.1007/s004030100218 ◽

2001 ◽

Vol 293 (4) ◽

pp. 165-170 ◽

Cited By ~ 12

Author(s):

Dean W. Brown ◽

B. S. Baker ◽

J.-M. Ovigne ◽

Vincent A. Fischetti ◽

Catherine Hardman ◽

...

Keyword(s):

T Cells ◽

Cell Wall ◽

Cd4 T Cells ◽

Protein S ◽

M Protein ◽

Group A Streptococci ◽

Group A ◽

Ifn Γ

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Correction for O'Toole et al., Two major classes in the M protein family in group A streptococci

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0604596103 ◽

2006 ◽

Vol 103 (31) ◽

pp. 11814-11814

Keyword(s):

Protein Family ◽

M Protein ◽

Group A Streptococci ◽

Group A

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STUDIES OF L FORMS AND PROTOPLASTS OF GROUP A STREPTOCOCCI

Journal of Experimental Medicine ◽

10.1084/jem.110.6.853 ◽

1959 ◽

Vol 110 (6) ◽

pp. 853-874 ◽

Cited By ~ 42

Author(s):

Earl H. Freimer ◽

Richard M. Krause ◽

Maclyn McCarty

Keyword(s):

Cell Wall ◽

Cell Walls ◽

M Protein ◽

Group A Streptococci ◽

Group A ◽

Isolated Cell ◽

Streptococcal Strain

L forms of Group A streptococci have been isolated by the use of penicillin gradient agar plates. Osmotically fragile protoplasts of Group A streptococci have been obtained by the use of Group C phage-associated lysin which lyses Group A streptococci and their isolated cell walls. Membranes surrounding these enzymatically derived protoplasts have been isolated, and chemical and immunological studies indicate that they are free of cell wall carbohydrate and M protein. The streptococcal protoplasts reproduce as colonies which are morphologically indistinguishable from streptococcal L forms. Evidence is presented to show that these two streptococcal derivatives are serologically and physiologically related to each other as well as to the parent streptococcal strain from which they were isolated.

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Antibodies against a Synthetic Peptide of SagA Neutralize the Cytolytic Activity of Streptolysin S from Group A Streptococci

Infection and Immunity ◽

10.1128/iai.70.4.2166-2170.2002 ◽

2002 ◽

Vol 70 (4) ◽

pp. 2166-2170 ◽

Cited By ~ 25

Author(s):

James B. Dale ◽

Edna Y. Chiang ◽

David L. Hasty ◽

Harry S. Courtney

Keyword(s):

Synthetic Peptide ◽

Neutralizing Antibodies ◽

Natural Infection ◽

Convincing Evidence ◽

Cytolytic Activity ◽

M Protein ◽

Group A Streptococci ◽

Streptolysin S ◽

Group A

ABSTRACT Virtually all group A streptococci (GAS) produce streptolysin S (SLS), a cytolytic toxin that is responsible for the beta-hemolysis surrounding colonies of the organisms grown on blood agar. SLS is an important virulence determinant of GAS, and recent studies have identified a nine-gene locus that is responsible for synthesis and transport of the toxin. SLS is not immunogenic; thus, no neutralizing antibodies are evoked during the course of natural infection. In the present study, we show that a synthetic peptide containing amino acid residues 10 to 30 of the putative SLS (SagA) propeptide [SLS(10-30)] coupled to keyhole limpet hemocyanin evoked antibodies in rabbits that completely neutralized the hemolytic activity of the toxin in vitro. Inhibition of hemolysis was reversed by preincubation of the immune serum with soluble, unconjugated peptide, indicating the specificity of the antibodies. In addition, antibodies that were affinity purified over an SLS(10-30) peptide column completely inhibited SLS-mediated hemolysis. The SLS(10-30) antisera did not opsonize group A streptococci; however, when combined with type-specific M protein antisera, the SLS antibodies significantly enhanced phagocytosis mediated by M protein antibodies. Thus, we have shown for the first time that it is possible to raise neutralizing antibodies against one of the most potent bacterial cytolytic toxins known. Our data also provide convincing evidence that the sagA gene actually encodes the SLS peptide of GAS. The synthetic peptide may prove to be an important component of vaccines designed to prevent GAS infections.

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