Identification of a new diagnostic antigen for glanders using immunoproteome analysis

Area of Science:

• Veterinary Microbiology
• Immunology
• Proteomics

Background:

• Glanders is a highly contagious and zoonotic disease affecting equids, caused by the bacterium Burkholderia mallei.
• Burkholderia mallei is classified as a Biosafety Level 3 pathogen and a significant biothreat agent, necessitating robust diagnostic strategies.
• Current diagnostic methods for glanders can be time-consuming, highlighting the need for simple and rapid tools for disease control and surveillance.

Purpose of the Study:

• To identify potential protein antigens of Burkholderia mallei for the development of a diagnostic test for glanders.
• To evaluate the diagnostic potential of identified antigens, specifically GroEL, in serological assays for glanders.

Main Methods:

• Proteomic analysis and 2D immunoblotting using equine sera were employed to identify immunoreactive protein antigens of Burkholderia mallei.
• The gene encoding the identified GroEL protein was cloned and expressed in E. coli, followed by purification using Ni-NTA affinity chromatography.
• Recombinant GroEL protein was utilized in an Enzyme-Linked Immunosorbent Assay (ELISA) to test a panel of known glanders-positive and negative equine serum samples.

Main Results:

• Twelve potential protein antigens of Burkholderia mallei with diagnostic potential were identified through proteomic and immunoblotting techniques.
• Key immunoreactive proteins identified include GroEL, translation elongation factor Tu, elongation factor Ts, arginine deiminase, malate dehydrogenase, and DNA-directed RNA polymerase subunit alpha.
• The developed ELISA using recombinant GroEL demonstrated high diagnostic accuracy, with a sensitivity of 96% and a specificity of 98.7% when tested against equine sera.

Conclusions:

• The study successfully identified GroEL as a promising candidate antigen for the serodiagnosis of glanders.
• The recombinant GroEL-based ELISA shows significant potential for a sensitive and specific diagnostic tool for glanders, aiding in disease control efforts.
• Further validation and implementation of this GroEL-based diagnostic assay could greatly improve the management and eradication of glanders in equine populations.