Monoclonal Antibody-Based Biosensor for Point-of-Care Detection of Type III Secretion System Expressing Pathogens

Area of Science:

• Microbiology
• Immunology
• Biotechnology

Background:

• Antibiotic resistance is a growing global health crisis, projected to cause 10 million deaths annually by 2050.
• Rapid and accurate diagnostic tools are crucial to combatting bacterial infections and the spread of resistance.
• The bacterial type 3 secretion system (T3SS) is a key virulence factor in many Gram-negative pathogens.

Purpose of the Study:

• To develop a novel monoclonal antibody targeting the EspB protein of the T3SS.
• To assess the antibody's specificity, affinity, stability, and functionality for diagnostic applications.
• To integrate the antibody into an electrochemical biosensor for pathogen detection.

Main Methods:

• Development and characterization of a monoclonal antibody (mAb-EspB-B7) against the EspB protein.
• Epitope mapping using competitive enzyme-linked immunosorbent assay (ELISA).
• Integration of mAb-EspB-B7 into an electrochemical biosensor platform.

Main Results:

• mAb-EspB-B7 demonstrated high affinity and specificity for both recombinant and native EspB proteins.
• The antibody remained stable across various pH, temperature, and salt concentration conditions, and functional in human serum.
• The developed electrochemical biosensor showed high sensitivity and specificity in detecting T3SS antigens and intact pathogenic bacteria.

Conclusions:

• mAb-EspB-B7 is a promising candidate for developing rapid and precise diagnostic tools against T3SS-harboring pathogens.
• The conserved epitope recognized by the antibody facilitates differentiation between commensal and pathogenic bacteria.
• Future development of point-of-care biosensors with multiplexing capabilities is feasible for broad pathogen detection.