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Assembly of human contact phase factors and release of bradykinin at the surface of curli-expressing Escherichia coli

På svenska

Author

  • Abdelhakim Ben Nasr
  • Arne Olsén
  • Ulf Sjöbring
  • Werner Müller-Esterl
  • Lars Björck

Summary, in English

Previous work has demonstrated that most strains of the human pathogen Streptococcus pyogenes bind kininogens through M protein, a fibrous surface protein and virulence determinant. Here we find that strains of several other pathogenic bacterial species, both Gram-positive and Gram-negative, isolated from patients with sepsis, also bind kininogens, especially kininogen (HK). The most pronounced interaction was seen between HK and Escherichia coli. Among clinical isolates of E. coli, the majority of the enterohaemorrhagic, enterotoxigenic, and sepsis strains, but none of the enteroinvasive and enteropathogenic strains, bound HK. Binding of HK to E. coli correlated with the expression of curli, another fibrous bacterial surface protein, and the binding of HK to purified curli was specific, saturable, and of high affinity; Ka = 9 x 10(7) M-1. Other contact phase proteins such as factor XI, factor XII, and prekallikrein bound to curliated E. coli, but not to an isogenic curli-deficient mutant strain, suggesting that contact phase activation may occur at the surface of curliated bacteria. Kininogens are also precursor molecules of the vasoactive kinins. When incubated with human plasma, curli-expressing bacteria absorbed HK. Addition of purified plasma kallikrein to the HK-loaded bacteria resulted in a rapid and efficient release of bradykinin from surface-bound HK. The assembly of contact phase factors at the surface of pathogenic bacteria and the release of the potent proinflammatory and vasoactive peptide bradykinin, should have a major impact on the host-microbe relationship and may contribute to bacterial pathogenicity and virulence.

Publishing year

1996

Language

English

Pages

35-927

Publication/Series

Molecular Microbiology

Volume

20

Issue

5

Document type

Journal article

Publisher

Wiley-Blackwell

Topic

  • Microbiology in the medical area

Status

Published

ISBN/ISSN/Other

  • ISSN: 1365-2958