Role of streptococcal pyrogenic exotoxin B in the mouse model of group A streptococcal infection.
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| Abstract |
Streptococcal pyrogenic exotoxin B (SPE B) is a cysteine protease produced by Streptococcus pyogenes. In this study, the differences in virulence between protease-positive clinical isolates and their protease-negative mutants were examined in a mouse model. Isogenic protease-negative mutants were constructed by homologous recombination, using integrational plasmids to disrupt the speB gene. These mutants caused less mortality and tissue damage than protease-positive strains when inoculated into BALB/c mice via air pouch, suggesting that SPE B cysteine protease plays an important role in the pathogenesis of S. pyogenes infection. Reconstitution of SPE B in the air pouches increased the mortality of mice receiving the speB mutant strain. Infiltrated cell numbers in the exudates from the air pouches of mice infected with SPE B-producing S. pyogenes were higher than those from mice infected with protease-negative mutants at 12 h. However, despite pretreatment with vinblastine to deplete neutrophils, injection of protease-positive bacteria still resulted in severe tissue injury, indicating that neutrophil infiltration may not be the major factor involved in SPE B-enhanced tissue damage. The role of SPE B was further confirmed by demonstrating that SPE B immunization of mice conferred protection from challenge with a lethal dose of protease-positive bacteria.
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| Authors | C F Kuo, J J Wu, K Y Lin, P J Tsai, S C Lee, Y T Jin, H Y Lei, Y S Lin |
| Journal | Infection and immunity (Infect Immun) Vol. 66 Issue 8 Pg. 3931-5 (Aug 1998) ISSN: 0019-9567 [Print] United States |
| PMID | 9673282 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't) |
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