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

Balaji, P.; S anthi, D.; P rabhavathi, M.; Raja, A .

International Journal of Medical Microbiology; 2018; 308(2): 297-305.

Abstract: High global prevalence of latent TB infection (LTBI) is a key challenge in distinguishing patients with active pulmonary TB (PTB) from those with LTBI. The functional pro?le of CD4 + and CD8 + T cell cytokines produced as a response to Mycobacterium tuberculosis antigens vary during the course of tuberculosis (TB) infection. We evaluated antigen-speci?c CD4 + and CD8 + T cell cytokine response after overnight in vitro stimulation of peripheral blood with mycobacterial antigens ESAT-6, CFP-10, Rv2204c, Rv0753c and Rv0009 by ?ow cytometry. A signi?cantly higher frequency of antigen-speci?c CD4 + or CD8 + IFN-?+ T cells were found in LTBI than in PTB. Among all the antigens used, Rv2204c-speci?c CD8+ IFN-?+ displayed the positivity of 72% and 24% in LTBI and PTB respectively. In contrast to IFN-?, the frequencies of CD4 + or CD8 + secreting TNF-a + cells were signi?cantly high in PTB compared to LTBI. CD8 + TNF-a + analysis showed 60% positivity in PTB and 13.6% positivity in LTBI against Rv0753c antigen stimulation. We also predicted Rv2204c speci?c CD8 + T cells secreting IL-10 or IL-4 showed maximum di?erentiation between LTBI and PTB. In conclusion, altered expression of Rv2204c-speci?c CD 4 +IFN-?+ and CD 8 +IL-4 + T cells in LTBI and PTB might be a useful biomarker to di?erentially diagnose LTBI and active TB.

Keywords: Latent tuberculosis; Active tuberculosis; Biomarker; Antigen-speci?c T cell response; Multifunctional T cell; Interferon gamma; Interleukins

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