Article

Differential binding of Shiga toxin 2 to human and murine neutrophils.

Department of Microbiology and Infectious Diseases, University of Calgary Health Sciences Centre, Calgary, Alberta, Canada.
Journal of Medical Microbiology (impact factor: 2.5). 12/2007; 56(Pt 11):1423-30. DOI:10.1099/jmm.0.47282-0 pp.1423-30
Source: PubMed

ABSTRACT Shiga toxins (Stx1 and Stx2) are responsible for initiating haemolytic uraemic syndrome, a serious extraintestinal complication caused by enterohaemorrhagic Escherichia coli O157 : H7 infection in humans. Shiga toxins are classical AB(5)-type exotoxins, consisting of a globotriaosylceramide (Gb(3))-binding B subunit pentamer and an enzymic A subunit. It is demonstrated in this study that Stx2 binds to human neutrophils by a non-classical mechanism that is independent of Gb(3). In contrast, the investigation revealed that Stx2 binds to murine neutrophils by the classical Gb(3)-dependent mechanism. Moreover, whereas the human serum amyloid P (HuSAP) component inhibited Stx2 binding to murine neutrophils, HuSAP increased Stx2 binding to human neutrophils by 84.2 % (P< or =0.002, Student's t-test). These observations may explain why HuSAP protects mice from the lethal effects of Stx2, whereas there is no indication that HuSAP plays a similar protective role in humans infected by E. coli O157 : H7.

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Keywords

classical Gb(3)-dependent mechanism
 
enterohaemorrhagic Escherichia coli O157
 
Gb(3))-binding B subunit pentamer
 
H7 infection
 
human serum amyloid P
 
independent
 
initiating haemolytic uraemic syndrome
 
lethal effects
 
serious extraintestinal complication
 
Shiga toxins
 
similar protective role
 
Student's t-test
 
Stx2
 
Stx2 binding
 
Stx2 binds
 
subunit
 

Thomas P Griener