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Antigen-specific precursor frequency impacts T cell proliferation, differentiation, and requirement for costimulation.

Ford ML, Koehn BH, Wagener ME, Jiang W, Gangappa S, Pearson TC, Larsen CP - J. Exp. Med. (2007)

Bottom Line: Using an adoptive transfer system to incrementally raise the precursor frequency of antigen-specific CD8(+) T cells, we found that donor-reactive T cells primed at low frequency exhibited increased cellular division, decreased development of multifunctional effector activity, and an increased requirement for CD28- and CD154-mediated costimulation relative to those primed at high frequency.The results demonstrated that recipients with low CD4(+) and CD8(+) donor-reactive T cell frequencies exhibited long-term skin graft survival upon CD28/CD154 blockade, whereas simultaneously raising the frequency of CD4(+) T cells to approximately 0.5% and CD8(+) T cells to approximately 5% precipitated graft rejection despite CD28/CD154 blockade.These results demonstrate a critical role for initial precursor frequency in determining the CD8(+) T cell requirement for CD28- and CD154-mediated costimulatory signals during graft rejection.

View Article: PubMed Central - PubMed

Affiliation: Department of Surgery and Emory Transplant Center, Emory University, Atlanta, GA 30322, USA.

ABSTRACT
After a brief period of antigenic stimulation, T cells become committed to a program of autonomous expansion and differentiation. We investigated the role of antigen-specific T cell precursor frequency as a possible cell-extrinsic factor impacting T cell programming in a model of allogeneic tissue transplantation. Using an adoptive transfer system to incrementally raise the precursor frequency of antigen-specific CD8(+) T cells, we found that donor-reactive T cells primed at low frequency exhibited increased cellular division, decreased development of multifunctional effector activity, and an increased requirement for CD28- and CD154-mediated costimulation relative to those primed at high frequency. The results demonstrated that recipients with low CD4(+) and CD8(+) donor-reactive T cell frequencies exhibited long-term skin graft survival upon CD28/CD154 blockade, whereas simultaneously raising the frequency of CD4(+) T cells to approximately 0.5% and CD8(+) T cells to approximately 5% precipitated graft rejection despite CD28/CD154 blockade. Antigenic rechallenge of equal numbers of cells stimulated at high or low frequency revealed that cells retained an imprint of the frequency at which they were primed. These results demonstrate a critical role for initial precursor frequency in determining the CD8(+) T cell requirement for CD28- and CD154-mediated costimulatory signals during graft rejection.

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Reduced numbers of functional effector cells in CTLA-4 Ig– and anti-CD154–treated mice with low precursor frequency of graft-specific cells. 106 or 107 OT-I T cells (along with 106 OT-II cells) were adoptively transferred into naive B6 recipients before transplantation with an mOVA skin graft. (A) IFN-γ production by cells primed at low versus high frequency in the presence or absence of CTLA-4 Ig/ anti-CD154 was measured as the percentage of Thy1.1+ CD8+ T cells that stained positive for intracellular anti–IFN-γ after a 4-h in vitro peptide stimulation. (B) The absolute number of cytokine-producing effector cells that secreted IFN-γ or TNF-α was calculated by multiplying the percentage of cytokine-positive cells by the total number of OT-I T cells as determined by TruCount analysis. Results indicate that both the percentage (A and not depicted) and absolute numbers (B) of IFN-γ– and TNF-α–secreting cells were diminished in mice primed at low but not high frequency in the presence of CTLA-4 Ig/anti-CD154. These data are representative examples of four independent experiments, with two to three mice per group per experiment.
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fig5: Reduced numbers of functional effector cells in CTLA-4 Ig– and anti-CD154–treated mice with low precursor frequency of graft-specific cells. 106 or 107 OT-I T cells (along with 106 OT-II cells) were adoptively transferred into naive B6 recipients before transplantation with an mOVA skin graft. (A) IFN-γ production by cells primed at low versus high frequency in the presence or absence of CTLA-4 Ig/ anti-CD154 was measured as the percentage of Thy1.1+ CD8+ T cells that stained positive for intracellular anti–IFN-γ after a 4-h in vitro peptide stimulation. (B) The absolute number of cytokine-producing effector cells that secreted IFN-γ or TNF-α was calculated by multiplying the percentage of cytokine-positive cells by the total number of OT-I T cells as determined by TruCount analysis. Results indicate that both the percentage (A and not depicted) and absolute numbers (B) of IFN-γ– and TNF-α–secreting cells were diminished in mice primed at low but not high frequency in the presence of CTLA-4 Ig/anti-CD154. These data are representative examples of four independent experiments, with two to three mice per group per experiment.

Mentions: Based on our observations that OT-I T cells primed at low frequency in vivo were quantitatively susceptible to the effects of costimulation blockade, whereas OT-I T cells primed at high frequency were able to overcome the induction of tolerance, we hypothesized that T cells primed at high versus low frequency in the absence of CD28- and CD154- mediated costimulatory signals might also be qualitatively different on a per cell basis in terms of their abilities to produce the effector cytokines IFN-γ and TNF-α. Although cells stimulated at high frequency in the presence or absence of costimulation blockade exhibited similar frequencies of IFN-γ– and TNF-α–producing cells 4 h after in vitro peptide rechallenge, cells primed at low precursor frequency in the presence of costimulation blockade exhibited a dramatically diminished ability to make IFN-γ and TNF-α as compared with their untreated counterparts (Fig. 5 A and not depicted). The same result was observed when the total number of IFN-γ– or TNF-α–secreting cells per spleen was analyzed (Fig. 5 B). This striking result closely parallels the observed clinical outcome of graft rejection, as mice that received a low precursor frequency of OT-I T cells in the presence of costimulation blockade were the only group in which long-term tolerance was induced (Fig. 3 A).


Antigen-specific precursor frequency impacts T cell proliferation, differentiation, and requirement for costimulation.

Ford ML, Koehn BH, Wagener ME, Jiang W, Gangappa S, Pearson TC, Larsen CP - J. Exp. Med. (2007)

Reduced numbers of functional effector cells in CTLA-4 Ig– and anti-CD154–treated mice with low precursor frequency of graft-specific cells. 106 or 107 OT-I T cells (along with 106 OT-II cells) were adoptively transferred into naive B6 recipients before transplantation with an mOVA skin graft. (A) IFN-γ production by cells primed at low versus high frequency in the presence or absence of CTLA-4 Ig/ anti-CD154 was measured as the percentage of Thy1.1+ CD8+ T cells that stained positive for intracellular anti–IFN-γ after a 4-h in vitro peptide stimulation. (B) The absolute number of cytokine-producing effector cells that secreted IFN-γ or TNF-α was calculated by multiplying the percentage of cytokine-positive cells by the total number of OT-I T cells as determined by TruCount analysis. Results indicate that both the percentage (A and not depicted) and absolute numbers (B) of IFN-γ– and TNF-α–secreting cells were diminished in mice primed at low but not high frequency in the presence of CTLA-4 Ig/anti-CD154. These data are representative examples of four independent experiments, with two to three mice per group per experiment.
© Copyright Policy
Related In: Results  -  Collection

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fig5: Reduced numbers of functional effector cells in CTLA-4 Ig– and anti-CD154–treated mice with low precursor frequency of graft-specific cells. 106 or 107 OT-I T cells (along with 106 OT-II cells) were adoptively transferred into naive B6 recipients before transplantation with an mOVA skin graft. (A) IFN-γ production by cells primed at low versus high frequency in the presence or absence of CTLA-4 Ig/ anti-CD154 was measured as the percentage of Thy1.1+ CD8+ T cells that stained positive for intracellular anti–IFN-γ after a 4-h in vitro peptide stimulation. (B) The absolute number of cytokine-producing effector cells that secreted IFN-γ or TNF-α was calculated by multiplying the percentage of cytokine-positive cells by the total number of OT-I T cells as determined by TruCount analysis. Results indicate that both the percentage (A and not depicted) and absolute numbers (B) of IFN-γ– and TNF-α–secreting cells were diminished in mice primed at low but not high frequency in the presence of CTLA-4 Ig/anti-CD154. These data are representative examples of four independent experiments, with two to three mice per group per experiment.
Mentions: Based on our observations that OT-I T cells primed at low frequency in vivo were quantitatively susceptible to the effects of costimulation blockade, whereas OT-I T cells primed at high frequency were able to overcome the induction of tolerance, we hypothesized that T cells primed at high versus low frequency in the absence of CD28- and CD154- mediated costimulatory signals might also be qualitatively different on a per cell basis in terms of their abilities to produce the effector cytokines IFN-γ and TNF-α. Although cells stimulated at high frequency in the presence or absence of costimulation blockade exhibited similar frequencies of IFN-γ– and TNF-α–producing cells 4 h after in vitro peptide rechallenge, cells primed at low precursor frequency in the presence of costimulation blockade exhibited a dramatically diminished ability to make IFN-γ and TNF-α as compared with their untreated counterparts (Fig. 5 A and not depicted). The same result was observed when the total number of IFN-γ– or TNF-α–secreting cells per spleen was analyzed (Fig. 5 B). This striking result closely parallels the observed clinical outcome of graft rejection, as mice that received a low precursor frequency of OT-I T cells in the presence of costimulation blockade were the only group in which long-term tolerance was induced (Fig. 3 A).

Bottom Line: Using an adoptive transfer system to incrementally raise the precursor frequency of antigen-specific CD8(+) T cells, we found that donor-reactive T cells primed at low frequency exhibited increased cellular division, decreased development of multifunctional effector activity, and an increased requirement for CD28- and CD154-mediated costimulation relative to those primed at high frequency.The results demonstrated that recipients with low CD4(+) and CD8(+) donor-reactive T cell frequencies exhibited long-term skin graft survival upon CD28/CD154 blockade, whereas simultaneously raising the frequency of CD4(+) T cells to approximately 0.5% and CD8(+) T cells to approximately 5% precipitated graft rejection despite CD28/CD154 blockade.These results demonstrate a critical role for initial precursor frequency in determining the CD8(+) T cell requirement for CD28- and CD154-mediated costimulatory signals during graft rejection.

View Article: PubMed Central - PubMed

Affiliation: Department of Surgery and Emory Transplant Center, Emory University, Atlanta, GA 30322, USA.

ABSTRACT
After a brief period of antigenic stimulation, T cells become committed to a program of autonomous expansion and differentiation. We investigated the role of antigen-specific T cell precursor frequency as a possible cell-extrinsic factor impacting T cell programming in a model of allogeneic tissue transplantation. Using an adoptive transfer system to incrementally raise the precursor frequency of antigen-specific CD8(+) T cells, we found that donor-reactive T cells primed at low frequency exhibited increased cellular division, decreased development of multifunctional effector activity, and an increased requirement for CD28- and CD154-mediated costimulation relative to those primed at high frequency. The results demonstrated that recipients with low CD4(+) and CD8(+) donor-reactive T cell frequencies exhibited long-term skin graft survival upon CD28/CD154 blockade, whereas simultaneously raising the frequency of CD4(+) T cells to approximately 0.5% and CD8(+) T cells to approximately 5% precipitated graft rejection despite CD28/CD154 blockade. Antigenic rechallenge of equal numbers of cells stimulated at high or low frequency revealed that cells retained an imprint of the frequency at which they were primed. These results demonstrate a critical role for initial precursor frequency in determining the CD8(+) T cell requirement for CD28- and CD154-mediated costimulatory signals during graft rejection.

Show MeSH
Related in: MedlinePlus