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Characterization of complement factor H binding to Yersinia enterocolitica serotype O:3
Marta Biedzka-Sarek1, Hanna Jarva, Heidi Hyytiäinen
1Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, 00014 Helsinki, Finland.
Infection and Immunity
|July 16, 2008
Summary
Yersinia enterocolitica O:3 uses outer membrane proteins YadA and Ail to bind factor H (FH), a complement regulator. This binding helps the bacteria evade immune attack, highlighting a key bacterial immune evasion strategy.
Area of Science:
- Microbiology
- Immunology
- Bacterial Pathogenesis
Background:
- Bacteria evade the complement system, a key immune defense, by binding host proteins.
- Factor H (FH) is a crucial negative regulator of the alternative complement pathway.
Purpose of the Study:
- To investigate how Yersinia enterocolitica O:3 binds FH.
- To identify the bacterial surface proteins involved in FH binding and their functional significance.
Main Methods:
- Utilized Y. enterocolitica O:3 mutant strains lacking specific outer membrane proteins.
- Employed truncated recombinant FH constructs to map binding sites.
- Assessed the functional activity of bound FH through complement component cleavage assays.
Main Results:
- The outer membrane protein YadA is the primary receptor for FH on Y. enterocolitica O:3.
- The outer membrane protein Ail also contributes to FH binding under specific conditions.
- Bound FH retained cofactor activity for factor I-mediated C3b cleavage, indicating functional binding.
- Ail binds FH to short consensus repeats 6 and 7, while YadA binds FH broadly across the molecule.
Conclusions:
- Yersinia enterocolitica O:3 actively recruits functional FH to its surface via YadA and Ail.
- FH binding is a significant mechanism contributing to the complement resistance of this pathogen.
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