ROP-ESAT6-CFP10 as Tuberculosis-Specific Antigen in Interferon Gamma Release Assay

Area of Science:

• Immunology
• Infectious Diseases
• Biotechnology

Background:

• Interferon-gamma release assays (IGRAs) are crucial for tuberculosis (TB) diagnosis.
• Existing IGRAs rely on specific antigens like ESAT6 and CFP10.
• Development of novel, cost-effective TB antigens is essential for improving diagnostic accessibility.

Purpose of the Study:

• To evaluate a newly developed tuberculosis (TB)-specific antigen, ROP-ESAT6-CFP10, for use in interferon-gamma release assays (IGRAs).
• To compare the performance of ROP-ESAT6-CFP10 in an ELISpot assay against established IGRAs: QuantiFERON-TB Gold (QFT) and T-SPOT.TB.

Main Methods:

• The study enrolled 35 TB patients and 20 healthy volunteers.
• Samples were tested using QFT, T-SPOT.TB, and an ELISpot assay with ROP-ESAT6-CFP10 at two concentrations (1 μg and 5 μg) as the TB-specific antigen (ROP-TB).
• Agreement between the different IGRA methods was statistically evaluated.

Main Results:

• High agreement was observed between ROP-TB (1 μg) and T-SPOT.TB (79.1%, kappa=0.483) and between ROP-TB (1 μg) and QFT (76.7%, kappa=0.557).
• Excellent agreement was found between the two concentrations of ROP-TB (95.3%, kappa=0.894).
• No significant difference in the median number of spots was found between T-SPOT.TB and ROP-TB assays in TB patients.

Conclusions:

• The ELISpot assay utilizing the novel ROP-ESAT6-CFP10 antigen demonstrates good concordance with established IGRAs (T-SPOT.TB and QFT).
• Recombinant overlapping peptide (ROP) technology offers potential for reduced manufacturing costs.
• ROP-ESAT6-CFP10 is a promising TB-specific antigen for developing more affordable and accessible IGRAs.