Identification of a new diagnostic antigen for glanders using immunoproteome analysis.

This research article discusses the identification of a new antigen, GroEL, which can be used to diagnose glanders, a disease affecting horses, donkeys and mules caused by the Burkholderia mallei pathogen, using immunoproteome analysis.

Understanding Glanders and the Need for Diagnostic Tools

• Glanders is a disease primarily affecting equine species such as horses, donkeys, and mules, but it’s also considered a biothreat agent due its potential use in bioweapon sanitation.
• The disease is caused by the Burkholderia mallei pathogen, a biorisk group 3 pathogen. Diseases of this category have potential for large-scale dissemination and typically require special action for public health preparedness.
• Given the mentioned risks, the development of simple and rapid diagnostic tools for glanders is essential. It is for this purpose that the research was carried out.

Identification of Diagnostic Antigens Using Proteomic Approach

• The researchers used a proteomic approach, a large-scale study of proteins, for the identification of diagnostic antigens. Combined with equine sera, the approach helped identify 12 protein antigens that were viable for diagnostic purposes.
• Several immunoreactive proteins, such as GroEL, translation elongation factor Tu, elongation factor Ts, arginine deiminase, malate dehydrogenase, and DNA-directed RNA polymerase subunit alpha, were identified using this approach.

Selection and Evaluation of GroEL

• Out of the identified proteins, the researchers chose GroEL for thorough evaluation. They cloned and expressed it in E. coli before purifying it using Ni-NTA affinity chromatography, a widely-used method for purifying recombinant proteins.
• The recombinant GroEL protein was assessed in ELISA format. ELISA is a diagnostic tool often used in medicine to detect antigens or antibodies present in a sample.
• For effective evaluation of GroEL’s diagnostic potentials, a panel of glanders positive (n=49) and negative (n=79) equine serum samples was used. The developed ELISA had a sensitivity and specificity of 96% and 98.7%, respectively, showing high accuracy for glanders diagnosis.
• These results significantly indicate the potential of GroEL in serodiagnosis, or blood serum testing, of glanders.