Rv2204c, Rv0753c and Rv0009 antigens specific T cell responses in latent and active TB - a flow cytometry-based...

Area of Science:

• Immunology
• Infectious Diseases
• Microbiology

Background:

• Latent tuberculosis infection (LTBI) poses a global health challenge, complicating the differentiation from active pulmonary tuberculosis (PTB).
• T-cell cytokine profiles in response to Mycobacterium tuberculosis antigens differ between LTBI and PTB states.

Purpose of the Study:

• To evaluate antigen-specific CD4+ and CD8+ T-cell cytokine responses for distinguishing LTBI from PTB.
• To identify potential biomarkers for differential diagnosis of tuberculosis infection types.

Main Methods:

• Peripheral blood from LTBI and PTB patients was stimulated in vitro with Mycobacterium tuberculosis antigens (ESAT-6, CFP-10, Rv2204c, Rv0753c, Rv0009).
• Antigen-specific CD4+ and CD8+ T-cell cytokine production (IFN-γ, TNF-α, IL-10, IL-4) was measured using flow cytometry.

Main Results:

• Higher frequencies of antigen-specific CD4+ or CD8+ IFN-γ+ T cells were observed in LTBI compared to PTB.
• Rv2204c-specific CD8+ IFN-γ+ T cells showed 72% positivity in LTBI vs. 24% in PTB.
• CD4+ or CD8+ TNF-α+ cells were significantly higher in PTB than LTBI, particularly against Rv0753c antigen.
• Rv2204c-specific CD8+ T cells secreting IL-10 or IL-4 demonstrated significant differentiation between LTBI and PTB.

Conclusions:

• Altered expression of Rv2204c-specific CD4+IFN-γ+ and CD8+IL-4+ T cells may serve as valuable biomarkers.
• These T-cell responses offer potential for the differential diagnosis of LTBI and active TB.