J Korean Pediatr Soc.  2003 Feb;46(2):143-153.

Relationship between Gb3 Expression and Cytotoxicity of Shiga-like Toxin I

Affiliations
  • 1Department of Pediatrics, Chonnam National University Medical School, Kwangju, Korea.
  • 2Department of Microbiology, Pusan National University College of Medicine, Pusan, Korea. immunpym@pusan.ac.kr
  • 3Department of Immunology, Pusan National University College of Medicine, Pusan, Korea.
  • 4Medical Research Center, Dong-A University College of Medicine, Pusan, Korea.

Abstract

PURPOSE
Infection with Shiga-like toxin (SLT)-producing Escherichia coli, an emerging human pathogen found particularly in young children under 5 years of age, causes a spectrum of illnesses with high morbidity and mortality, ranging from diarrhea to hemorrhagic colitis and hemolytic uremic syndrome. Host mediators play an important role in the pathogenesis of SLT-I toxicity. The experiments described here were designed to investigate the effect of SLT-I on TNF- alpha production and to understand the effect of TNF-alpha on GB3 expression. We also further examine the relationship between the Gb3 level and the differential susceptibility of cells to the cytotoxic action of SLT-I.
METHODS
The effect of purified SLT-1 from E. coli O157 : H7 (ATCC 43890) on tumor necrosis factor-alpha (TNF- alpha) production in Raw264.7 cells was investigated. Many mediators regulate endothelial cell membrane expression of the glycolipid globotriaosyleramide (Gb3), which serves as the toxin receptor, suggesting that the host response to the toxin or other bacterial products may contribute to pathogenesis by regulating target cell sensitivity to the toxins. Therefore, the relationships between Gb3 expression and cytotoxicity against SLT-I on three types of cells were evaluated.
RESULTS
Detectable levels of TNF-alpha were produced as early as six hours after induction and continued to increase during 48 hours by SLT-I. It was also found that Vero cells and dendritic cells (DC2.4 cells) expressed high levels of Gb3, 83% and 68%, respectively, and that Raw264.7 cells had a low level of Gb3 (29%) and appeared refractory to cytotoxicity against SLT-I. Vero cells and DC2.4 cells expressing high levels of Gb3 were highly susceptible to SLT-I. Furthermore, macrophages showed a resistance to SLT-I cytotoxicity, despite the fact that Gb3 expression was enhanced.
CONCLUSION
These results strongly suggest that the expression of Gb3 is necessary but not sufficient to confer sensitivity of macrophages to SLT-I and further underpin the important role of SLT-I and its Gb3 receptors in the pathogenesis of E. coli O157 infection.

Keyword

E. coli O157; Shiga-like toxin; tumor necrosis factor- alpha; glycolipid globotriaosyleramide

MeSH Terms

Child
Colitis
Dendritic Cells
Diarrhea
Endothelial Cells
Escherichia coli
Hemolytic-Uremic Syndrome
Humans
Macrophages
Membranes
Mortality
Shiga Toxin 1*
Tumor Necrosis Factor-alpha
Vero Cells
Shiga Toxin 1
Tumor Necrosis Factor-alpha
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