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Towards a DNA vaccine against tuberculosis
D B Lowrie1, R E Tascon, M J Colston
1Laboratory for Leprosy and Mycobacterial Research, National Institute for Medical Research, London, UK.
Vaccine
|December 1, 1994
Summary
Generating cell-mediated immunity against tuberculosis (TB) is possible by expressing the Mycobacterium leprae hsp65 gene. This approach protects mice and involves T cells, including CD8 cells that target infected macrophages.
Area of Science:
- Immunology
- Microbiology
- Genetics
Background:
- Tuberculosis (TB) remains a significant global health challenge.
- Developing effective vaccines and immunotherapies for TB is crucial.
- Mycobacterial antigens are key targets for immune responses.
Purpose of the Study:
- To investigate the potential of expressing the Mycobacterium leprae hsp65 gene for inducing cell-mediated protection against Mycobacterium tuberculosis.
- To evaluate the role of CD4 and CD8 T cells in adoptive transfer of protection.
- To assess the cytotoxic activity of CD8 T cells against M. tuberculosis-infected macrophages.
Main Methods:
- Expression of the M. leprae hsp65 gene in adult Balb/c mice using three different delivery methods: retroviral vectors in tumor cells, in vitro transfected bone marrow cells for reconstitution, and plasmid DNA injection into muscle.
- Isolation and cloning of CD4 and CD8 T cells from immunized mice.
- Passive transfer of cloned T cells to non-immunized recipients.
- Assessing protection against M. tuberculosis challenge.
- Evaluating the lysis of M. tuberculosis-infected macrophages by CD8 T cells.
Main Results:
- Expression of the M. leprae hsp65 gene conferred substantial cell-mediated protection against M. tuberculosis challenge in mice.
- Both CD4 and CD8 T cells transferred protection passively.
- CD8 T cells demonstrated selective lysis of M. tuberculosis-infected macrophages.
Conclusions:
- The M. leprae hsp65 gene holds promise as a target for developing TB vaccines.
- Cell-mediated immunity, particularly involving CD8 T cells, plays a critical role in protection against M. tuberculosis.
- Different gene delivery strategies can be employed to achieve protective immunity.