Description of a novel adhesin of Mycobacterium avium subsp. paratuberculosis

Area of Science:

• Microbiology
• Cell Biology
• Immunology

Background:

• Mycobacterium avium subsp. paratuberculosis (MAP) infection relies on host cell binding and ingestion.
• Fibronectin (FN) mediates the interaction between MAP and host cells.
• Identifying MAP adhesion molecules is crucial for understanding its pathogenesis.

Purpose of the Study:

• To identify and characterize fibronectin (FN) binding cell wall proteins of Mycobacterium avium subsp. paratuberculosis (MAP).
• To investigate the role of specific MAP surface proteins in host cell adhesion and internalization.

Main Methods:

• A cell wall protein fraction from MAP was obtained and analyzed using 2D electrophoresis.
• Immunoreactive spots were identified by MALDI-TOF MS and homology searches.
• Fibronectin (FN) binding capability of candidate proteins, including elongation factor Tu (EF-Tu), was assessed using ligand blot assays, ELISA, and surface plasmon resonance.

Main Results:

• Elongation factor Tu (EF-Tu) was identified as a potential FN-binding protein.
• EF-Tu demonstrated direct binding to FN in a dose-dependent manner.
• Surface plasmon resonance analysis revealed a dissociation constant for EF-Tu in the μM range.

Conclusions:

• Elongation factor Tu (EF-Tu) is a fibronectin (FN)-binding protein on Mycobacterium avium subsp. paratuberculosis (MAP).
• EF-Tu may play a significant role in the interaction of MAP with host epithelial cells via FN binding.
• These findings contribute to understanding MAP pathogenesis and potential therapeutic targets.