Human antibodies to bacterial superantigens and their ability to inhibit T-cell activation and lethality

Bacterial superantigens (BSAgs) cause massive stimulation of the immune sys tem and are associated with various pathologies and diseases. To address th e role of antibodies in protection against BSAgs, we screened the sera of 2 9 human volunteers for antibodies to the SAgs staphylococcal enterotoxin A (SEA), SEB, SEC1, and toxic shock syndrome toxin 1 (TSST-1). Although all v olunteers had detectable levels of antibodies against SEB and SEC1, many (9 out of 29 volunteers) lacked detectable antibody to SEA or had minimal tit ers, Antibody titers to TSST-1 were well below those to SEB and SEC1, and t hree volunteers lacked detectable antibody to this BSAg. In addition, poole d immunoglobulin preparations obtained from different companies had antibod y titers against SEs and TSST-1. There was a good correlation between antib ody titers and inhibition of superantigenic effects of these toxins. Transf er of SEB-specific antibodies, obtained from pooled sera, suppressed in vit ro T-cell proliferation and totally protected mice against SEB. These data suggest that the inhibitory activity of human sera was specific to antibodi es directed against the toxins. Thus, it may be possible to counteract with specific antibodies BSAg-associated pathologies caused by stimulation of t he immune system.