Shiga Like Toxin 2

Shiga-like toxins (Stx) are a group of toxins produced by certain strains of Escherichia coli (E. coli), particularly those associated with severe foodborne illnesses. These toxins are structurally and functionally similar to the Shiga toxin produced by Shigella dysenteriae. Among the various types of Shiga-like toxins, Shiga-like toxin 2 (Stx2) is known for its potent cytotoxic effects and its role in causing hemolytic-uremic syndrome (HUS) and hemorrhagic colitis in humans .

Shiga-like toxin 2 (Stx2) is a member of the AB5 toxin family, which consists of one enzymatically active A subunit and five receptor-binding B subunits . The B subunits form a pentameric ring that binds to globotriaosylceramide (Gb3) receptors on the surface of target cells . Upon binding, the toxin is internalized, and the A subunit exerts its toxic effect by inhibiting protein synthesis in the host cell .

The recombinant form of the Stx2 B subunit is produced through genetic engineering techniques. This involves cloning the gene encoding the B subunit and expressing it in a suitable host, such as E. coli . The recombinant B subunit retains its ability to bind to Gb3 receptors but lacks the toxic A subunit, making it a valuable tool for research and potential therapeutic applications .

1. Immunoprophylaxis: Research has shown that the recombinant Stx2 B subunit can induce an immune response in animal models, providing protection against the toxic effects of the holotoxin . This suggests potential for developing vaccines or immunotherapies against Stx2-producing E. coli infections .

2. Cancer Therapy: The Gb3 receptor, which the Stx2 B subunit targets, is overexpressed in certain cancer cells . This property has been exploited to develop targeted drug delivery systems and imaging agents for cancer therapy .

3. Diagnostic Tools: The binding specificity of the Stx2 B subunit to Gb3 receptors can be utilized in diagnostic assays to detect the presence of Gb3-expressing cells or tissues .