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Bacterial superantigens reactivate antigen-specific CD8+ memory T cells
1Department of Immunology, St Jude Children's Research Hospital, Memphis, TN 38105, USA.
International Immunology
|October 6, 1997
Summary
Bacterial superantigens, like staphylococcal enterotoxins (SE), can activate CD8+ memory T cells, contrary to previous beliefs. This immune response involves T cell proliferation and effector function, potentially altering the CD8+ memory T cell pool.
Area of Science:
- Immunology
- Microbiology
- Cellular Biology
Background:
- Superantigens typically activate naive T cells via TCR V beta specificity.
- Memory T cells were previously thought to be unresponsive to superantigen stimulation.
Purpose of the Study:
- To investigate the response of CD8+ memory T cells to superantigen stimulation.
- To determine if staphylococcal enterotoxins (SE) can activate influenza virus-specific CD8+ memory cytotoxic T lymphocytes (CTLs).
Main Methods:
- In vivo challenge of memory mice with SEB and in vitro stimulation of splenic T cells with SEA or SEB.
- Analysis of CTL activity and T cell activation mechanisms.
- Purification and culture of CD8+ CD62L loCD44hi memory phenotype T cells with SE.
Main Results:
- SE challenge in memory mice generated vigorous influenza-specific CTL activity.
- In vitro SEA or SEB stimulation induced influenza-specific CTLs from memory T cells, but not naive T cells.
- Purified CD8+ memory T cells proliferated and secreted lymphokines in response to SE, indicating direct T cell receptor engagement.
Conclusions:
- CD8+ memory T cells are responsive to superantigen stimulation, exhibiting proliferation and effector function.
- Bacterial superantigen exposure may potentially perturb the CD8+ T cell memory pool.