Death by superantigen

Death by a B Cell Superantigen

Amongst the many ploys used by microbial pathogens to interfere with host immune responses is the production of proteins with the properties of superantigens. These properties enable superantigens to interact with conserved variable region framework subdomains of the antigen receptors of lymphocytes rather than the complementarity determining region involved in the binding of conventional antig...

Negative Selection by IgM Superantigen

Complement activation by a B cell superantigen.

Staphylococcal protein A (SpA), acting as a B cell superantigen, binds to the Fab region of human VH3+ Igs. Using SpA abrogated of its IgG Fc binding activity (Mod SpA) as a model B cell superantigen, we determined whether such an interaction causes complement activation. Addition of Mod SpA to human serum led to complement consumption and the generation of C3a. To determine whether this comple...

Superantigen antagonist peptides

The production of superantigenic exotoxins by Gram positive bacteria underlies the pathology of toxic shock syndrome. Future treatment strategies for superantigen-mediated diseases are likely to be directed at blocking the three-way interaction between superantigen, T cell receptor and major histocompatibility class II molecule, which inititates an excessive and disordered inflammatory response...

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 (...