The streptococcal cysteine protease SpeB is not a natural immunoglobulin-cleaving enzyme.

The streptococcal cysteine protease SpeB is not a natural immunoglobulin 2 cleaving enzyme

Selective modulation of superantigen-induced responses by streptococcal cysteine protease.

Streptococcal pyrogenic exotoxin (Spe) B, a streptococcal cysteine protease, is believed to be important in group A streptococcal (GAS) pathogenesis. The present study examined the effect of SpeB on the activity of superantigenic exotoxins secreted by M1T1 GAS isolates. The proliferative response of human lymphocytes to culture supernatant (SUP) from an SpeB(+) isolate increased significantly (...

The M protein is dispensable for maturation of streptococcal cysteine protease SpeB.

The streptococcal pyrogenic exotoxin B (SpeB) is an important virulence factor of group A streptococci (GAS) with cysteine protease activity. Maturation of SpeB to a proteolytically active form was suggested to be dependent on cell-wall-anchored M1 protein, the major surface protein of GAS (M. Collin and A. Olsen, Mol. Microbiol. 36:1306-1318, 2000). Collin and Olsen showed that mutant GAS stra...

Cleavage of antigen-bound immunoglobulin G by SpeB contributes to streptococcal persistence in opsonizing blood.

Group A streptococci (GAS) express a superantigen, SpeB, having cysteine protease activity. SpeB exhibits several properties that might contribute to virulence, the most recently discovered being the ability to cleave immunoglobulin G (IgG) in a manner similar to that of papain. In the present study, we confirmed this latter finding and found that the irreversible inhibition of SpeB protease ac...

Role of group A Streptococcus HtrA in the maturation of SpeB protease.

The serine protease high-temperature requirement A (HtrA) (DegP) of the human pathogen Streptococcus pyogenes (group A Streptococcus; GAS) is localized to the ExPortal secretory microdomain and is reportedly essential for the maturation of cysteine protease streptococcal pyrogenic exotoxin B (SpeB). Here, we utilize HSC5 (M5 serotype) and the in-frame isogenic mutant HSC5DeltahtrA to determine ...