Selenium reduces enterohemorrhagic Escherichia coli O157:H7 verotoxin production and globotriaosylceramide receptor expression on host cells

This study investigated the efficacy of selenium (Se) in reducing Escherichia coli O157:H7 verotoxin production and toxin gene expression. Additionally, the effect of Se on globotriaosylceramide (Gb3) receptor in human lymphoma cells was determined. The effect of Se on verotoxin synthesis was determined by standard ELISA, whereas its effect on Gb3 receptor was determined by flow cytometry and real-time quantitative PCR. Se reduced extracellular and intracellular verotoxin concentration by 40-60% and 80-90%, respectively (p < 0.05), and downregulated verotoxin genes (p < 0.05). Se reduced Gb3 receptor synthesis in lymphoma cells, and real-time quantitative PCR data revealed a significant downregulation of LacCer synthase gene (GalT2) involved in Gb3 synthesis. Further studies are warranted to validate these results in an appropriate animal model.