Therapy modulates the response to T cell epitopes over the spectrum of tuberculosis infection

Background

Identifying stage-specific antigens is essential for developing tuberculosis (TB) diagnostics and vaccines. In a low TB endemic country, we characterized, the Mycobacterium tuberculosis (Mtb)-specific immune response to a pool of Mtb-derived epitopes (ATB116), demonstrated as associated with TB disease.

Methods

In this prospective observational cross-sectional study, we enrolled healthy donors (HD), subjects with TB disease, and TB infection (TBI) at baseline and therapy completion. T-cell response after whole blood stimulation with the peptide pools was characterized by ELISA, flow cytometry, and multiplex assay.

Results

ATB116-specific IFN-γ response (by ELISA) significantly associates with Mtb regardless of infection/disease (p < 0.0001) and decreases during TB therapy (p = 0.0002). Flow cytometry confirms that ATB116-specific CD4⁺ T-cell response associated with Mtb regardless of infection/disease (p < 0.0001) and shows a significantly higher frequency of IFN-γ/IL-2 and central memory T-cells in TBI compared to TB (p = 0.016; p = 0.0242, respectively). CD4⁺ T cell-specific response decreases after TB therapy completion. The antigen-specific CD8⁺ T-cell response mirrors the CD4⁺ response. Finally, the multiplex assay analysis showed that ATB116 induces several immune factors in both TB and TBI.

Conclusion

We characterized the immune response to Mtb peptide pools that is modulated by TB therapy. These results are important for our understanding of TB immunopathogenesis and vaccine design.