We analyzed the responses of several T cell fractions reactive with superantigenic toxins (SAGTs), staphylococcal enterotoxin A (SEA), or Yersinia pseudotuberculosis-derived mitogen (YPM) in mice implanted with mini-osmotic pumps filled with SEA or YPM. In mice implanted with the SEA pump, SEA-reactive Vbeta3(+)CD4(+) T cells exhibited a high-level protracted expansion for 30 days, and SEA-reac...

The in vivo rabbit ileum was used to study the relationship of cholera enterotoxin-induced water and electrolyte secretion and mucus secretion and to determine whether the enterotoxin influenced the intestinal mucus blanket. In experiments in which luminal fluid viscosity was used to assess mucus secretion, it was found that while cholera enterotoxin induced a sustained secretion of water and e...

The role of TCR ligand density (i.e. the number of antigen-MHC complexes) in modulating the diversity of a T cell response selected from a pool of naive precursors remains largely undefined. By measuring early-activation markers up-regulation and proliferation following stimulation with staphylococcal enterotoxin A (SEA), we demonstrate that decreasing the ligand dose below an optimal concentra...

Superantigens exert their pathologic effects by direct binding to major histocompatibility complex (MHC) class II molecules and T cell antigen receptors (TCR), thus circumventing the normal, antigen-specific immune response. A direct link between disease and toxin suggests an excellent opportunity for vaccine intervention. Site-directed mutants of staphylococcal enterotoxin A (SEA) that have at...

Bacterial superantigens induce peripheral unresponsiveness in CD4+ T cell populations that express appropriate Vbeta chains. We have used Vbeta3/Valpha11 T cell receptor transgenic (Tg) mice and the Vbeta3-specific superantigen staphylococcal enterotoxin A (SEA) to further investigate the mechanisms that contribute to such unresponsiveness. As in other models, in vivo exposure to SEA rendered t...

Previous studies indicated that enterotoxin B production by staphylococci was strongly inhibited by slight reductions in water activity (a(w)) levels. Similar studies reported herein, employing an enterotoxin A-producing strain, indicated that this organism was capable of producing enterotoxin at a much lower a(w) level than that required for enterotoxin B production. Staphylococcal growth rate...

Immunologic cross-reactivity between Streptococcus pyogenes type A exotoxin (erythrogenic toxin) and Staphylococcus aureus enterotoxins B and C1 was demonstrated by Ouchterlony double diffusion, Western immunoblot, and immunodot analyses. Specific antiserum to type A streptococcal exotoxin reacted more strongly with staphylococcal enterotoxin B than with enterotoxin C1. The reactivity of type A...

This report examines the genetic basis for Salmonella typhimurium Q1 enterotoxin production. A 918-base-pair XbaI-HincII fragment of plasmid pJM17, composed of cholera toxin (CT) coding sequences (ctxAB), was used as a gene probe. With this probe, the S. typhimurium enterotoxin was identified on a 6.3-kilobase EcoRI-PstI fragment of chromosomal DNA from plasmidless strain Q1. We cloned this 6.3...

BACKGROUND Rheumatoid arthritis (RA) is the most common chronic inflammatory disease. The staphylococcal superantigens are considered as the causative agent of RA disease. OBJECTIVES This study aimed to assess the presence of staphylococcal enterotoxin D in synovial fluid and blood of patients with RA. PATIENTS AND METHODS A total of 120 blood and SF samples of patients with RA were studied...

Staphylococcus succinus subsp. succinus type strain DSM 14617 was isolated from plant and soil inclusions within 25- to 35-million-year-old Dominican amber. The complete genome sequence of strain DSM 14617T includes a genome of 2.88 Mb (32.94% G+C content) without any plasmids.