Document Detail


Mouse toxicity and cytokine release by verotoxin 1 B subunit mutants.
MedLine Citation:
PMID:  11119557     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The crystal structure of the verotoxin 1 (VT1) B subunit complexed with a globotriaosylceramide (Gb(3)) analogue showed the presence of three receptor binding sites per monomer. We wished to study the effects of altering the three sites, singly or in combination, on animal toxicity and cytokine induction in vitro. We found that while the site 1 and 2 mutants were modestly (two- to sevenfold) reduced in their ability to cause disease in BALB/c mice, the site 3 mutant, W34A, was as toxic as VT1. However, all the double-mutant proteins, irrespective of which two sites were mutated, exhibited approximately a 100-fold reduction in their 50% lethal doses for mice. These results suggest that multivalent receptor binding is important in vivo and that all three binding sites make a similar contribution to the latter process. The triple-mutant holotoxin, F30A G62T W34A, administered intraperitoneally without adjuvant, stimulated a strong antibody response in BALB/c mice, and the immune sera neutralized the activity of VT1 in vitro. Induction of tumor neurosis factor alpha release from differentiated human monocytes (THP-1 cells) was relatively impaired for site 1 and site 2 but not site 3 mutants, suggesting an auxiliary role for the latter site in mediation of cytokine release in vitro. Cytotoxicity assays on undifferentiated THP-1 cells have also demonstrated the importance of sites 1 and 2 and the relatively small role played by site 3 in causing cell death. These data suggest an association between the cytotoxicity of the protein and its ability to induce cytokine release.
Authors:
V M Wolski; A M Soltyk; J L Brunton
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Infection and immunity     Volume:  69     ISSN:  0019-9567     ISO Abbreviation:  Infect. Immun.     Publication Date:  2001 Jan 
Date Detail:
Created Date:  2001-01-18     Completed Date:  2001-01-18     Revised Date:  2013-04-17    
Medline Journal Info:
Nlm Unique ID:  0246127     Medline TA:  Infect Immun     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  579-83     Citation Subset:  IM    
Affiliation:
Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cell Line
Escherichia coli / pathogenicity*
Female
Glycosides / immunology
Humans
Mice
Mice, Inbred BALB C
Monocytes / drug effects,  metabolism
Mutation
Protein Subunits
Shiga Toxins / immunology,  metabolism,  toxicity*
Trihexosylceramides / metabolism
Triterpenes / immunology
Tumor Necrosis Factor-alpha / biosynthesis*
Chemical
Reg. No./Substance:
0/Glycosides; 0/Protein Subunits; 0/Shiga Toxins; 0/Trihexosylceramides; 0/Triterpenes; 0/Tumor Necrosis Factor-alpha; 37341-37-0/stichoposide; 71965-57-6/globotriaosylceramide
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