Shiga toxin 2e subunit B (Stx2eB)

Shiga toxin 2e (Stx2e) is a member of the AB5 family of bacterial toxins produced by certain strains of Escherichia coli, primarily associated with swine edema disease. The B subunit (Stx2eB) forms a pentameric structure that is responsible for the specific binding of the toxin to its cellular receptor, globotetraosylceramide (Gb4), which is highly expressed on the vascular endothelial cells of pigs [2, 7, 11]. This binding event is the essential first step in the toxin's pathogenesis, as it triggers the retrograde transport and internalization of the catalytic A subunit into the host cell cytoplasm [6, 11]. Once inside, the A subunit inhibits protein synthesis by depurinating the 28S ribosomal RNA, leading to cell death and the characteristic clinical signs of edema and neurological distress [4, 6]. Because the B subunit is non-toxic on its own but critical for toxin entry, it serves as a primary target for the development of veterinary vaccines, such as Ecoporc SHIGA, and experimental neutralizing antibodies [27, 32, 38]. These therapeutic interventions aim to induce a humoral immune response that blocks the B subunit's interaction with its receptor, thereby preventing the toxin from entering cells and causing disease [11, 38].

Other names

Verotoxin 2e B subunitVT2eBSLT-IIe B subunitShiga-like toxin 2e B subunitstxB2e

The B subunit pentamer binds to the globotetraosylceramide (Gb4) receptor on the surface of host cells, facilitating the entry of the toxic A subunit into the cytoplasm. Vaccines targeting the B subunit induce neutralizing antibodies that block this binding and prevent toxin-mediated cell death [11, 27, 38].