Population tailored modification of tuberculosis specific interferon-gamma release assay

Area of Science:

• Immunology
• Infectious Diseases
• Biotechnology

Background:

• Blood-based Interferon-Gamma Release Assays (IGRA) are crucial for detecting Mycobacterium tuberculosis (MTB) sensitization.
• Current IGRA sensitivity is limited in individuals with human immunodeficiency virus (HIV).
• The QuantiFERON-TB Gold In-Tube test utilizes peptide 38-55 of Rv2654c, with potential for improvement.

Purpose of the Study:

• To fine-map T cell responses to Rv2654c peptides to enhance MTB detection sensitivity.
• To improve the performance of IGRA in both HIV-uninfected and HIV-infected populations.

Main Methods:

• Utilized Interferon-gamma ELISpot assay to map peptide epitopes of Rv2654c in HIV-uninfected individuals with latent and active tuberculosis.
• Tested a modified IGRA incorporating a newly identified peptide in HIV-uninfected and HIV-infected cohorts in South Africa.

Main Results:

• Identified a peptide epitope between amino acids 51-65 (p51-65) of Rv2654c as highly recognized.
• The modified IGRA showed significantly increased quantitative performance in HIV-uninfected individuals (p=0.002).
• In HIV-infected individuals, a modest increase in positive responders was observed after 3 months of antiretroviral therapy (ART).

Conclusions:

• Specific synthetic peptides can be used to tailor the detection of MTB sensitization.
• Interferon-gamma release assays can be optimized for improved diagnostic performance in diverse populations.
• Further research may lead to more sensitive diagnostics for tuberculosis infection, particularly in immunocompromised individuals.