Recombinant Mycobacterium avium Elongation factor Tu (tuf)
Description
Adhesion and Host Interaction
rEF-Tu binds host extracellular matrix proteins like fibronectin (Fn) with high affinity (dissociation constant K<sub>D</sub> = 605 nM) . This interaction facilitates bacterial adherence to epithelial cells, as demonstrated in Mycoplasma hyopneumoniae and M. avium subsp. paratuberculosis (MAP):
-
Blocking EF-Tu with antibodies reduced bacterial adhesion to swine tracheal epithelial cells (STEC) by 46% .
-
rEF-Tu competitively inhibits mycobacterial attachment to Fn-coated surfaces .
Immune Modulation
rEF-Tu triggers antibody responses in infected hosts but exhibits cross-reactivity:
-
64% of MAP-infected cattle sera recognized rEF-Tu, though healthy and M. bovis-infected cattle also showed reactivity .
-
Antigenic epitopes are conserved across mycobacteria, limiting diagnostic specificity .
Surface Localization and Processing
EF-Tu is surface-exposed in M. avium subsp. hominissuis and processed into fragments under infection-mimicking conditions . Proteomic profiling identified EF-Tu as a core surface protein across multiple culture conditions :
| Culture Condition | Unique Peptides (24h/48h) |
|---|---|
| 7H9 medium | 9/7 |
| DMEM (host mimic) | 13/11 |
| Intracellular | 4/8 |
Interaction with Host Proteins
rEF-Tu binds plasminogen, enabling its conversion to plasmin—a protease that degrades host tissues—in the presence of host activators .
Diagnostic and Vaccine Development
-
Antigen Screening: rEF-Tu is evaluated in interferon-γ release assays (IGRAs) for MAP detection, though cross-reactivity remains a challenge .
-
Vaccine Candidates: EF-Tu is included in multi-antigen formulations to enhance sensitivity .
Challenges and Future Directions
Product Specs
Target Background
KEGG: mav:MAV_4489
