Staphylococcal enterotoxin B (SEB)

Staphylococcal enterotoxin B (SEB) is a bacterial protein toxin and superantigen produced by Staphylococcus aureus. SEB functions as a potent virulence factor responsible for staphylococcal food poisoning and is a leading cause of toxic shock syndrome. It achieves its effects by simultaneously binding to major histocompatibility complex (MHC) class II molecules on antigen-presenting cells and T-cell receptors (TCR) on T cells, specifically cross-linking them in a manner independent of antigen specificity and resulting in massive, polyclonal T-cell activation. This leads to an uncontrolled release of pro-inflammatory cytokines (a "cytokine storm"), which can cause severe inflammation, shock, and potentially death[1][3][6]. Structurally, SEB is a stable protein with a distinctive two-domain fold and is capable of withstanding high temperatures, remaining active even after boiling for short periods[6][9]. SEB does not possess enzymatic activity but exerts its toxicological effects via immune modulation as a superantigen. Due to its potency, stability, and ease of production, SEB is classified as a potential biological warfare agent and remains a target for the development of inhibitory therapeutics and diagnostic methods[9]. Experimental drug candidates include peptides that can interfere with SEB binding to immune receptors, reducing pathological immune activation[7].

Other names

Enterotoxin type BSEBStaphylococcus aureus enterotoxin B

Superantigen cross-links MHC class II molecules and T-cell receptors independent of antigen, massively activating T cells; Induces release of pro-inflammatory cytokines (cytokine storm); Some experimental peptides block SEB-TCR or SEB-CD28 binding to mitigate cytokine storm[7].