Journal Article

Synergistic effects of streptolysin S and streptococcal pyrogenic exotoxin B on the mouse model of group A streptococcal infection

Wu, Jiunn-Jong, Hung, Chih-Hsin, Chiang-Ni, Chuan, Tsao, Nina, Zeng, Yi-Fang, Kuo, Chih-Feng, Lin, Yee-Shin, Lu, Shiou-Ling

2012

Overview

Streptococcus pyogenes is a group A streptococcus (GAS) and an important human pathogen that causes a variety of diseases. Streptococcal pyrogenic exotoxin B (SPE B) and streptolysin S (SLS) are important virulence factors involved in GAS infection, but it is not clear which one is more virulent. Using an air pouch infection model, the wild-type strain NZ131, its isogenic mutants, and complementary mutants were used to examine the effects of SPE B and SLS on GAS infection. The results of the skin lesion and mouse mortality assays showed that although SPE B and SLS had a synergistic effect on GAS infection, SPE B played a more important role in local tissue damage while SLS had a more prominent effect on mouse mortality. Surveys of the exudates from the air pouch revealed that the expression of inflammatory cytokines was significantly inhibited in the sagB / speB- double-mutant JM4-infected mice. Furthermore, in vivo and in vitro studies showed that the isogenic mutant strains were more susceptible to the immune cell killing than the wild-type strain and that the sagB / speB- double-mutant JM4 was the most sensitive among these strains. Moreover, infection with the sagB / speB- double-mutant JM4 strain caused the least amount of macrophage apoptosis compared to infection with the wild-type NZ131 and the other complementary strains, which express only SPE B or SLS or both. Taken together, these results indicate that both SPE B and SLS contributed to GAS evasion from immune cell killing, local tissue damage, and mouse mortality.

• Publisher: Springer-Verlag,Springer,Springer Nature B.V
• Subject: Animals / Apoptosis / Bacterial Proteins - genetics / Bacterial Proteins - metabolism / Bacteriology / Biological and medical sciences / Biomedical and Life Sciences / Biomedicine / Disease Models, Animal / Drug Synergism / Exotoxins - genetics / Exotoxins - metabolism / Fundamental and applied biological sciences. Psychology / Humans / Immune Evasion / Immunology / Male / Medical Microbiology / Mice / Mice, Inbred BALB C / Microbiology / Mutation / Original Investigation / Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains / Pathogens / Streptococcal Infections - immunology / Streptococcal Infections - microbiology / Streptococcal Infections - mortality / Streptococcal Infections - pathology / Streptococcus infections / Streptococcus pyogenes / Streptococcus pyogenes - genetics / Streptococcus pyogenes - pathogenicity / Streptolysins - genetics / Streptolysins - metabolism / Virology / Virulence / Virulence Factors - genetics / Virulence Factors - metabolism