Role of streptococcal pyrogenic exotoxin B in the mouse model of group A streptococcal infection

Chih Feng Kuo, Jiunn Jong Wu, Kuei Yuan Lin, Pei Jane Tsai, Shiour Ching Lee, Ying Tai Jin, Huan Yao Lei, Yee Shin Lin

Research output: Contribution to journalArticlepeer-review

100 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)3931-3935
Number of pages5
JournalInfection and Immunity
Issue number8
Publication statusPublished - 1998 Aug

All Science Journal Classification (ASJC) codes

  • Parasitology
  • Microbiology
  • Immunology
  • Infectious Diseases

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