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Dynamic antigen-specific T-cell responses after point-source exposure to Mycobacterium tuberculosis
Katie Ewer1, Kerry A Millington, Jonathan J Deeks
1Tuberculosis Immunology Group, Nuffield Department of Clinical Medicine, University of Oxford, UK.
Summary
Antibiotic treatment reduced Mycobacterium tuberculosis-specific T cells in treated individuals. Untreated contacts showed a disappearance of these T cells, suggesting a resolving infection.
Area of Science:
- Immunology
- Infectious Diseases
- Tuberculosis Research
Background:
- T-cell kinetics are crucial for determining clinical outcomes in Mycobacterium tuberculosis infections.
- Understanding T-cell responses is key to managing tuberculosis (TB).
Purpose of the Study:
- To examine T-cell response kinetics in TB outbreak contacts with varying treatment and Tuberculin Skin Test (TST) statuses.
- To compare RD1-specific T-cell dynamics in treated vs. untreated individuals.
Main Methods:
- Utilized ex vivo IFN-gamma enzyme-linked immunospot assay (ELISpot) to track T cells.
- Monitored T cells specific for early secretory antigenic target 6 and culture filtrate protein 10 (RD1 antigens).
- Followed T-cell responses for 18 months post-TB exposure.
Main Results:
- Treated TST-positive students showed a significant annual decline (68%) in RD1-specific T cells.
- Untreated TST-positive staff maintained stable T-cell frequencies.
- Untreated TST-negative students displayed varied T-cell kinetics, with some becoming ELISpot-negative.
Conclusions:
- Antibiotic treatment likely reduces M. tuberculosis-specific T cells by decreasing bacterial load.
- Disappearance of M. tuberculosis-specific T cells in some untreated contacts suggests acute, resolving infections.