Effectiveness of Mycobacterium tuberculosis recombinant proteins-coated gold nanoparticles in improving the interferon-gamma release assay test.

INTRODUCTION

Gold nanoparticles (GNPs) are chemically inert, have low toxicity, and are easy to modify and functionalize for the detection of many pathogens. They have excellent immune modulatory and adjuvant properties. The aim of this study was to improve the diagnosis of latent tuberculosis infection (LTBI) by adding GNPs in tests based on interferon-gamma (IFN-γ) measurement.

METHODS

GNPs were coated with Mycobacterium tuberculosis (Mtb) recombinant proteins including TB10.4, CFP-10, ESAT-6, and TB7.7. Then, they exposed the whole blood of subjects with active tuberculosis (aTB), LTBI, and healthy controls (HC). Subsequently, IFN-γ produced in GNP tubes (QFT-NG) was measured and compared with IFN-γ produced in tubes without GNPs [QFT-A: (CFP-10, ESAT-6, TB7.7, TB10.4), QFT-B: (CFP-10, ESAT-6, TB7.7)].

RESULTS

The results showed that the IFN-γ production in the GNPs tubes was significantly higher than in tubes without GNPs in aTB, LTBI, and HC subjects. In aTB patients, the mean difference (MD) between the QFT-NG and QFT-A tubes was 0.44, with a P-value of 0.04, and a 95% CI: 0.07-0.88. Furthermore, in LTBI individuals, the QFT-NG and QFT-A tubes exhibited an MD=0.21, P-value=0.03, 95% CI: 0.15-0.4. In the aTB and LTBI subjects were detected in the QFT-NG tubes with a sensitivity of 95%, 100% and specificity 100%, 86%, respectively.

CONCLUSION

The use of GNPs coated with Mtb recombinant proteins can aid in detecting LTBI subjects by increasing IFN-γ levels.