TY - JOUR
T1 - Assembly of human contact phase factors and release of bradykinin at the surface of curli-expressing Escherichia coli
AU - Ben Nasr, Abdelhakim
AU - Olsén, Arne
AU - Sjöbring, Ulf
AU - Müller-Esterl, Werner
AU - Björck, Lars
PY - 1996
Y1 - 1996
N2 - 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.
AB - 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.
M3 - Article
SN - 1365-2958
VL - 20
SP - 927
EP - 935
JO - Molecular Microbiology
JF - Molecular Microbiology
IS - 5
ER -