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Peptide:MHC Tetramer-based Enrichment of Epitope-specific T cells
Published on: October 22, 2012
Antigen-specific precursor frequency impacts T cell proliferation, differentiation, and requirement for costimulation
Mandy L Ford1, Brent H Koehn, Maylene E Wagener
1Department of Surgery and Emory Transplant Center, Emory University, Atlanta, GA 30322, USA.
The Journal of Experimental Medicine
|January 31, 2007
Summary
Initial T cell precursor frequency significantly impacts immune responses during transplantation. Low precursor frequency leads to increased T cell division and reliance on costimulation, affecting graft survival.
Area of Science:
- Immunology
- Transplantation Biology
- Cellular Immunology
Background:
- T cells undergo expansion and differentiation after antigenic stimulation.
- Antigen-specific T cell precursor frequency is explored as a factor influencing T cell programming.
- Allogeneic tissue transplantation serves as the experimental model.
Purpose of the Study:
- To investigate the role of antigen-specific T cell precursor frequency in T cell programming.
- To determine how precursor frequency affects T cell expansion, differentiation, and effector function.
- To assess the impact of precursor frequency on immune responses during allogeneic transplantation.
Main Methods:
- Utilized an adoptive transfer system to manipulate precursor frequency of antigen-specific CD8(+) T cells.
- Compared T cells primed at low versus high precursor frequencies.
- Analyzed cellular division, effector activity, and costimulatory requirements (CD28, CD154).
- Evaluated skin graft survival in recipients with varying T cell precursor frequencies under costimulatory blockade.
Main Results:
- T cells primed at low precursor frequency showed increased division and reduced multifunctional effector activity.
- Low frequency priming led to a greater requirement for CD28 and CD154 costimulation.
- Recipients with low donor-reactive T cell frequencies had long-term skin graft survival after CD28/CD154 blockade.
- Elevated T cell precursor frequencies (0.5% CD4+, 5% CD8+) led to graft rejection despite blockade.
- Primed T cells retained an imprint of their initial precursor frequency upon rechallenge.
Conclusions:
- Initial T cell precursor frequency is a critical cell-extrinsic factor in T cell programming.
- Precursor frequency dictates the CD8(+) T cell requirement for CD28 and CD154 costimulation in graft rejection.
- Understanding precursor frequency dynamics is crucial for modulating immune responses in transplantation.
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