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Updated: Aug 8, 2026
Spatial and Temporal Control of T Cell Activation Using a Photoactivatable Agonist
Published on: April 25, 2018
Kinetics of T cell-activation molecules in response to Mycobacterium tuberculosis antigens
Paulo R Z Antas1, Eliane B Oliveira, Alexandre S Milagres
1Laboratório de Hanseníase, Instituto Oswaldo Cruz, Fiocruz, 21045-900 Rio de Janeiro, RJ, Brasil. pzuquim@ioc.fiocruz.br
Insights
This study tracked immune cell activation markers CD69 and CD25 in T lymphocytes responding to tuberculosis antigens. Results show distinct kinetic expressions, aiding in the development of new tuberculosis diagnostics and vaccines.
Area of Science:
- Immunology
- Cellular Biology
- Infectious Disease Research
Background:
- Understanding T lymphocyte activation is crucial for diagnosing and preventing infectious diseases like tuberculosis.
- Specific antigens like PPD, Ag85B, and ferritin are key targets for immune response evaluation.
Purpose of the Study:
- To analyze the kinetic expression of CD69 and CD25 activation markers on T lymphocytes after stimulation with mycobacterial antigens.
- To compare T cell responses to specific antigens versus a general mitogen (PHA).
- To assess the potential of these antigens for developing new tuberculosis diagnostics and vaccines.
Main Methods:
- Flow cytometry was used to measure CD69 and CD25 expression on CD4+ and CD8+ T cells.
- T cells from PPD-positive healthy individuals were stimulated in vitro with PPD, Ag85B, ferritin, and PHA.
- Kinetic analysis of marker expression over time (4h to 120h) was performed.
Main Results:
- PHA induced rapid CD69 expression (peak 24h) and later CD25 expression (peak 96h).
- Mycobacterial antigens elicited lower but significant responses, with CD25 high after 96h and CD69 after 24h.
- CD69 expression was significantly higher on CD8+ than CD4+ T cells. Ag85B primarily stimulated CD4+ T cells expressing CD25.
Conclusions:
- The study characterizes T cell activation kinetics in response to specific mycobacterial antigens.
- Findings support the evaluation of these antigens for novel tuberculosis diagnostic tools and vaccine development.
- Differential T cell subset responses (CD4+ vs. CD8+) to antigens like Ag85B provide insights for targeted immunotherapies.
Abstract:
The phenotypic features acquired subsequent to antigen-specific stimulation in vitro were evaluated by means of the kinetic expressions of CD69 and CD25 activation molecules on T lymphocytes and assayed by flow cytometry in response to PPD, Ag85B, and ferritin in PPD-positive healthy control individuals. In response to PHA, CD69 staining on both CD4+ and CD8+ T cells became initially marked after 4 h, peaked at 24 h, and quickly decreased after 120 h. For CD25, a latter expression was detected around 8 h, having increased after 96 h. As expected, the response rate to the mycobacterial antigens was much lower than that to the mitogen. Positive staining was high after 96 h for CD25 and after 24 h for CD69. CD69 expression was significantly enhanced (p < 0.05) on CD8+ as compared to CD4+ T cells. High levels were also found between 96-120 h. Regarding Ag85B, CD25+ cells were mostly CD4+ instead of CD8+ T cells. Moreover, in response to ferritin, a lower CD25 expression was noted. The present data will allow further characterization of the immune response to new mycobacterial-specific antigens and their evaluation for possible inclusion in developing new diagnostic techniques for tuberculosis as well in a new vaccine to prevent the disease.
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