Single-Cell Cytokine Gene Expression in Peripheral Blood Cells Correlates with Latent Tuberculosis Status

Area of Science:

• Immunology
• Molecular Biology
• Infectious Diseases

Background:

• Latent tuberculosis infection (LTBI) affects a significant portion of the global population.
• Accurate detection of host immune responses is crucial for managing infectious diseases like tuberculosis.
• Current methods for assessing T-cell responses can be time-consuming.

Purpose of the Study:

• To evaluate the correlation between antigen-specific T-cell responses measured by FISH-Flow and latent tuberculosis infection (LTBI).
• To assess the utility of FISH-Flow in rapidly measuring cytokine mRNA production in response to mycobacterial antigens.
• To characterize the immunophenotype of cytokine-producing cells in LTBI patients.

Main Methods:

• Peripheral-blood mononuclear cells (PBMCs) from LTBI-positive and LTBI-negative donors were stimulated ex vivo with mycobacterial antigens.
• RNA flow cytometry (FISH-Flow) was used to measure IFNG and IL2 mRNA production at the single-cell level.
• Conventional antibody-based staining was employed for immunophenotyping of cytokine mRNA-positive cells.

Main Results:

• A significant association was observed between LTBI status and the antigen-specific induction of IFNG and IL2 transcripts.
• FISH-Flow detected cytokine gene induction in a quarter of the time required for protein detection by ELISA.
• Antigen-driven cytokine mRNA induction primarily occurred in activated CD4+ T cells and was also detected in NK cells.

Conclusions:

• Antigen-driven T-cell cytokine mRNA induction, as measured by FISH-Flow, is a viable single-cell biomarker for host responses in latent tuberculosis.
• FISH-Flow provides a rapid, high-throughput method for assessing single-cell gene expression, complementing traditional immunophenotyping.
• Multi-scale, single-cell analyses hold promise for disease staging and monitoring therapeutic responses in tuberculosis and other infections.