The toxin plays a dominant role in the genesis of toxic shock in humans through a massive activation of the immune system. Thus, the effects on TCR binding of the His 135 residue could actually be mediated, wholly or in part, by the alpha 1 helix. Toxic shock syndrome toxin-1 (TSST-1) is one of a family of staphylococcal exotoxins recognized as microbial superantigens. In the molecular structure of the mutant toxin, the helix alpha 2 remains unaltered, but the His to Ala modification causes perturbations on the neighboring helix alpha 1 by disrupting helix-helix interactions.
In MCAS, mast cells mistakenly release too many chemical agents, resulting in symptoms in the skin, gastrointestinal tract, heart, respiratory, and neurologic systems. This residue, postulated to be directly involved in the toxin-TCR interactions, is located on the major helix alpha 2, which forms the backbone of the molecule and is exposed to the solvent. Mast cell activation syndrome (MCAS) causes a person to have repeated severe allergy symptoms affecting several body systems. The replacement of His 135 of TSST-1 with an Ala residue results in the loss of T-cell mitogenicity and toxicity in experimental animals. Severe COVID-19 is often associated with hypercytokinemia, which is typically found in macrophage activation syndrome. As we have not developed curative medicine and effective vaccine, the end of this life-threatening infectious disease is still unclear. The three-dimensional structure of a mutant (His-135-Ala) TSST-1 was compared with the structure of the native (wild-type) TSST-1 at 2.5 A resolution. An emerging, rapidly spreading coronavirus SARS-CoV-2 is causing a devastating pandemic. TSST-1, like other superantigens, can bind directly to class II major histocompatibility (MHC class II) molecules prior to its interaction with entire families of V beta chains of the T-cell receptor (TCR). Of note, some studies reported that the activation of primordial follicle could occur spontaneously after transplantation of frozen-thawed ovarian tissues using the conventional cryopreservation method (8284) and transient incubation with mTOR inhibitors extended the graft lifespan by preventing the massive activation (45, 85). Il va se traduire dans la MSA par l’apparition de cytopénies, d’une baisse du fibrinogène et d’une. Il est la conséquence d’une activation incontrôlée du système immunitaire, responsable d’une tempête cytokinique. This potentially lethal illness occurs as a result of the interaction of TSST-1 with a significant proportion of the T-cell repertoire. Le syndrome d’activation macrophagique (SAM) ou lympho-histiocytose hémophagocytaire (HLH) est une complication fréquente et parfois sévère de la MSA.
Toxic shock syndrome toxin-1 (TSST-1) is one of a family of staphylococcal exotoxins recognized as microbial superantigens.