Bacterial superantigen intoxication causes massive overactivation of T cells, which can result in potentially lethal toxic shock. Superantigens fall into two groups: superantigens such as staphylococcal enterotoxin B (SEB) that contain a single generic binding site for major histocompatibility complex class II (MHC-II) and more potent superantigens such as SEA with a second, zinc-dependent MHC-...

A growing body of evidence implicates streptococcal and staphylococcal superantigens in the development of psoriasis, atopic dermatitis and Kawasaki syndrome. In each of these illnesses, an abnormal state of immunologic activity is observed. Superantigens, which have a unique ability to activate large numbers of lymphocytes, are likely to contribute to these disorders in a number of ways. The d...

The ability of superantigens to activate large numbers of T cells suggests that they may play a role in the course of autoimmune disorders. Data from several animal models of autoimmune disorders including experimental allergic encephalomyelitis and collagen induced arthritis supports this hypothesis. Administration of bacterial superantigens can induce an exacerbation of the autoimmune process...

The species Staphylococcus aureus harbors 19 superantigen gene loci, six of which are located in the enterotoxin gene cluster (egc). Although these egc superantigens are far more prevalent in clinical S. aureus isolates than non-egc superantigens, they are not a prominent cause of toxic shock. Moreover, neutralizing Abs against egc superantigens are very rare, even among carriers of egc-positiv...

Superantigens are a family of bacterial and viral toxins that are able to induce a massive T-cell activation [1,2]. Compared to conventional antigens where only 0.0001-0.01% of T-cells are activated, superantigens are able to activate 10-30% of T-cells. Superantigen-induced T-cell activation results in an extensive production of inflammatory cytokines, such as tumor necrosis factor and interleu...

Superantigens are bacterial, viral, retroviral and some naturally occurring proteins that can specifically activate a large proportion of T and/or B cells. In contrast to classical peptide antigen recognition, superantigens do not require processing to small peptides. T-cell superantigens interact with the immune system by binding to major histocompatibility complex (MHC) class II proteins outs...

Superantigens are defined as proteins that activate a large number of T cells through interaction with the Vbeta region of the T cell antigen receptor (TCR). Here we demonstrate that the superantigen produced by Mycoplasma arthritidis (MAM), unlike six bacterial superantigens tested, interacts not only with the Vbeta region but also with the CDR3 (third complementarity-determining region) of TC...

Formation of the costimulatory axis between the B7-2 and CD28 coreceptors is critical for T-cell activation. Superantigens, Gram-positive bacterial virulence factors, cause toxic shock and sepsis by hyperinducing inflammatory cytokines. We report a novel role for costimulatory receptors CD28 and B7-2 as obligatory receptors for superantigens, rendering them therapeutic targets. We show that by ...

Endogenous superantigen-mediated thymic negative selection resulted in a paucity of mature T cells bearing T-cell receptor (TCR) Vbeta8 in the periphery. Consequently, the magnitude of immune response to exogenous superantigen staphylococcal enterotoxin B, which activates TCR Vbeta8(+) T cells, was significantly reduced and conferred protection from superantigen-induced mortality.