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Merck
  • Immune evasion of Enterococcus faecalis by an extracellular gelatinase that cleaves C3 and iC3b.

Immune evasion of Enterococcus faecalis by an extracellular gelatinase that cleaves C3 and iC3b.

Journal of immunology (Baltimore, Md. : 1950) (2008-10-23)
Shin Yong Park, Yong Pyo Shin, Chong Han Kim, Ho Jin Park, Yeon Sun Seong, Byung Sam Kim, Sook Jae Seo, In Hee Lee
초록

Enterococcus faecalis (Ef) accounts for most cases of enterococcal bacteremia, which is one of the principal causes of nosocomial bloodstream infections (BSI). Among several virulence factors associated with the pathogenesis of Ef, an extracellular gelatinase (GelE) has been known to be the most common factor, although its virulence mechanisms, especially in association with human BSI, have yet to be demonstrated. In this study, we describe the complement resistance mechanism of Ef mediated by GelE. Using purified GelE, we determined that it cleaved the C3 occurring in human serum into a C3b-like molecule, which was inactivated rapidly via reaction with water. This C3 convertase-like activity of GelE was shown to result in a consumption of C3 and thus inhibited the activation of the complement system. Also, GelE was confirmed to degrade an iC3b that was deposited on the Ag surfaces without affecting the bound C3b. This proteolytic effect of GelE against the major complement opsonin resulted in a substantial reduction in Ef phagocytosis by human polymorphonuclear leukocytes. In addition, we verified that the action of GelE against C3, which is a central component of the complement cascade, was human specific. Taken together, it was suggested that GelE may represent a promising molecule for targeting human BSI associated with Ef.

MATERIALS
제품 번호
브랜드
제품 설명

Sigma-Aldrich
Complement factor H from human plasma, 1 mg/mL in PBS, pH 7.2, ≥90% (SDS-PAGE)
Sigma-Aldrich
Complement C3 from human serum, ≥3000 C3H50 units/mg (using C3 deficient serum)
Sigma-Aldrich
Complement factor D from human plasma, 90-110 μg/mL in PBS, pH 7.2, ≥90% (SDS-PAGE)
Sigma-Aldrich
Complement C3 deficient serum human, substrate serum for C3 activity