The conventional paradigm of T cell activation through the TCR states that Lck plays a critical activating role in this signaling process. However, the T cell response to bacterial superantigens does not require Lck. In this study we report that not only is Lck dispensable for T cell activation by superantigens, but it actively inhibits this signaling pathway. Disruption of Lck function, either...

Staphylococcal enterotoxin B (SEB) is both a superantigen and toxin. As a superantigen, SEB can bind to major histocompatibility complex (MHC) class II molecules to form a ligand for alpha/beta T cell receptors bearing particular V beta elements. As a toxin, SEB causes rapid weight loss in mice sometimes leading to death. We show here that both of these functions map to the NH2-terminal portion...

The clinical, pathological, and immunological similarities between Kawasaki disease and the staphylococcal and streptococcal toxic shock syndromes suggest that a superantigen toxin may be involved in the pathogenesis of the disease. The V beta repertoire of peripheral blood mononuclear cells from 21 children with Kawasaki disease, 28 children with other illnesses, and 22 healthy controls were e...

Yersinia pseudotuberculosis-derived mitogen (YPM) is the unique Gram-negative bacillary superantigen known. In order to identify the regions on the YPM molecule involved in its superantigenic activity, seven overlapping peptides of the entire YPM molecule were synthesized and tested to evaluate their effects on the YPM-induced proliferation of human peripheral blood lymphocytes. A peptide corre...

We have used staphylococcal enterotoxin B (SEB) to study the role of naive and memory T cells in the induction of peripheral tolerance. After administration of SEB to mice, the numbers of naive and memory T cells increase, as does the proportion of memory T cells, which are unresponsive to further stimulation with SEB in vitro. In addition, memory T cells generated in response to conventional a...

Staphylococcus aureus bacteria utilize an extensive array of molecular countermeasures to manipulate the defensive microenvironment of the infected host and colonize potentially any tissue. The secreted polypeptides referred to as superantigens are unique among these countermeasures, because they target the multireceptor communication between T cells and antigen-presenting cells that is fundame...