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Gamma delta T lymphocytes in human tuberculosis.
P F Barnes1, C L Grisso, J S Abrams
1Department of Medicine, University of Southern California School of Medicine, Los Angeles 90033.
The Journal of Infectious Diseases
|March 1, 1992
Summary
Gamma delta T cells play a crucial role in immune resistance against tuberculosis. Higher percentages of these cells correlate with effective immunity, suggesting their importance in fighting Mycobacterium tuberculosis infection.
Area of Science:
- Immunology
- Microbiology
- Cell Biology
Background:
- Tuberculosis (TB) manifestations indicate the body's immune response to Mycobacterium tuberculosis (M. tuberculosis).
- Immune responses vary from protective and resistant (tuberculin reactors, tuberculous pleuritis) to ineffective (advanced pulmonary and miliary TB).
- Gamma delta T cells are a subset of T lymphocytes involved in innate and adaptive immunity.
Purpose of the Study:
- To investigate the role of gamma delta T cells in immune responses to tuberculous infection.
- To assess the expansion of gamma delta T cells in patients with different outcomes of M. tuberculosis infection.
- To evaluate the cytokine production by gamma delta T cells upon stimulation with M. tuberculosis.
Main Methods:
- Blood mononuclear cells were isolated from patients with varying degrees of TB and leprosy.
- Cells were cultured in vitro and stimulated with Mycobacterium tuberculosis.
- Expansion of gamma delta T cells was quantified using flow cytometry.
- Cytokine production (interferon-gamma, GM-CSF, IL-3, TNF-alpha) by M. tuberculosis-reactive gamma delta T cell lines was analyzed.
Main Results:
- Significantly higher percentages of gamma delta T cells were observed in patients with protective (tuberculin reactors) and resistant (tuberculous pleuritis) immunity compared to those with ineffective immunity (advanced pulmonary and miliary TB).
- In leprosy, greater gamma delta T cell expansion was seen in resistant tuberculoid leprosy patients than in unresponsive lepromatous leprosy patients.
- M. tuberculosis-reactive gamma delta T cells produced key cytokines like interferon-gamma, crucial for macrophage activation and potential mycobacterial elimination.
Conclusions:
- Gamma delta T cells are significantly expanded in individuals with effective immune responses to M. tuberculosis.
- These findings suggest that gamma delta T cells contribute to immune resistance against tuberculosis.
- Gamma delta T cells may play a vital role in controlling mycobacterial infections through cytokine-mediated macrophage activation.