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Preparing T Cell Growth Factor from Rat Splenocytes
Published on: November 1, 2007
T cell expansion is regulated by activated Gr-1+ splenocytes
T A Dietlin1, F M Hofman, W Gilmore
1Department of Neurology, University of Southern California Keck School of Medicine, Los Angeles, CA, USA.
Cellular Immunology
|August 9, 2005
Summary
Regulatory Gr-1+ splenic cells, including granulocytes and monocytes, control T cell expansion by producing nitric oxide (NO) and superoxide (O2-). These innate cells, activated by immunization, regulate adaptive immunity.
Area of Science:
- Immunology
- Cell Biology
Background:
- CD4+ T cell proliferation is regulated by the balance of nitric oxide (NO) and extracellular superoxide (O2-).
- Extracellular superoxide (O2-) enhances T cell proliferation and immune response intensity by reducing NO bioavailability.
Purpose of the Study:
- To investigate the role of Gr-1+ splenocytes in regulating Ag-specific T cell expansion.
- To determine the molecular mechanisms by which Gr-1+ splenocytes modulate T cell responses.
Main Methods:
- Analysis of NO and O2- production by spleen cells from naive and primed mice during T cell activation.
- Purification and characterization of splenic Gr-1+ cells.
- Assessment of the impact of immunization (CFA) on regulatory Gr-1+ cell populations.
- Comparison of regulatory cell presence in spleen versus draining lymph nodes.
Main Results:
- Spleen cells from naive mice did not produce NO or O2- during T cell activation.
- Gr-1+ splenocytes from primed mice produced both NO and O2-, regulating Ag-specific T cell expansion.
- Purified splenic Gr-1+ cells comprised granulocytes and monocytes.
- Activation/recruitment of these regulatory cells depended on CFA immunization.
- Regulatory Gr-1+ cells were absent in draining lymph nodes.
Conclusions:
- Innate Gr-1+ splenic cells, primarily granulocytes and monocytes, play a regulatory role in adaptive immunity.
- These cells modulate T cell expansion through the production of NO and O2-.
- The regulatory function of these cells is dependent on prior immunization and is localized to the spleen.
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