The Staphylococcal Superantigen-like Toxins
Ries J. Langley and John D. Fraser
from: Bacterial Toxins: Genetics, Cellular Biology and Practical Applications (Edited by: Thomas Proft). Caister Academic Press, U.K. (2013)
Staphylococcus aureus is a serious human pathogen responsible for a wide range of hospital and community acquired infections and deaths. It produces many virulence factors with functions involved first in invasion and then establishment and persistence within the body. Immune evasion is essential for survival of S. aureus in the host. The Staphylococcal Superantigen-like Proteins (SSLs), a family of recently discovered proteins expressed by all strains, play key roles in immune evasion by targeting important components of innate immunity. For example SSL7 blocks IgA from binding its Fc receptor on immune cells. IgA is the bodies' first line of defence against invading pathogens. SSL7 also binds the complement component C5 and prevents the cleavage of this molecule into its active fragments. The active fragment C5a has been shown to be of great importance in clearance of S. aureus. The binding of SSL10 to IgG1 prevents effector functions of this important class of antibody. Another sub-group of SSLs bind immune cell receptor proteins in a glycan-dependent manner to inhibit host immune defence against S. aureus. It is becoming clear that the SSLs are among the important arsenal of proteins that are responsible for immune evasion in S. aureus read more ...