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Fibronectin-binding activity in Borrelia burgdorferi1
D J Grab1, C Givens, R Kennedy
1Department of Parasitology, Tulane Regional Primate Research Center, Covington, LA, USA. grab@cc.saga-u.ac.jp
Abstract:
Recently, the term MSCRAMM (microbial surface components recognizing adhesive matrix molecules), has been introduced to describe microbial molecules that recognize extracellular matrix (ECM) [1]. Here we present evidence for the presence of fibronectin-binding molecules in Borrelia burgdorferi and several other Borrelia species. Immunofluorescence studies show that plasma fibronectin is bound uniformly over the cell surface of free swimming B. burgdorferi. In addition, the spirochetes are able to bind to plasma fibronectin-coated microwell plates, an interaction that is inhibited by anti-fibronectin antibody as well as exogenous plasma fibronectin. Taken together, the data suggest that fibronectin binds to the surface of the spirochete. On Western blot-like assays, B. burgdorferi and some B. afzelii strains express a major fibronectin-binding protein (Fn-BA) with an approximate molecular mass of 52 kDa. In addition, several other major Fn-BAs were found in B. hermsii (26, 31, 33, 39, 46, 54 and 58 kDa) and B. turicatae (39, 41, 45, 50, 56, 59 and 66 kDa). Preliminary evidence suggests that fibronectin (and Fn-BA) may play a role as a molecular bridge between the spirochete and other components of the extracellular matrix.
Insights
Borrelia burgdorferi and related species possess surface molecules that bind to fibronectin, a component of the host extracellular matrix. These fibronectin-binding proteins (Fn-BAs) may facilitate spirochete adhesion and interaction with host tissues.
Area of Science:
- Microbiology
- Molecular Biology
- Immunology
Background:
- Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMM) are key to pathogen-host interactions.
- The extracellular matrix (ECM) plays a crucial role in cellular structure and communication.
- Understanding pathogen adhesion mechanisms is vital for developing effective treatments.
Purpose of the Study:
- To investigate the presence and characteristics of fibronectin-binding molecules on Borrelia burgdorferi and other Borrelia species.
- To determine the role of these molecules in the interaction between Borrelia and the host extracellular matrix.
Main Methods:
- Immunofluorescence microscopy to visualize fibronectin binding on B. burgdorferi.
- Microtiter plate assays to quantify spirochete binding to fibronectin.
- Western blot-like assays to identify and characterize fibronectin-binding proteins (Fn-BAs).
Main Results:
- Plasma fibronectin uniformly binds to the surface of B. burgdorferi.
- Borrelia species demonstrate significant binding to fibronectin, which can be inhibited by anti-fibronectin antibodies and excess fibronectin.
- B. burgdorferi and B. afzelii express a major 52 kDa Fn-BA, while other Borrelia species exhibit multiple Fn-BAs of varying molecular masses.
Conclusions:
- Borrelia species possess surface molecules that bind to host fibronectin.
- Fibronectin-binding proteins (Fn-BAs) on Borrelia spirochetes are identified.
- Fn-BAs likely act as molecular bridges, mediating the interaction between spirochetes and the extracellular matrix, potentially contributing to pathogenesis.