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Inhibition of Donor-Reactive CD8+ T Cell Responses by Selective CD28 Blockade Is Independent of Reduced ICOS Expression.

Liu D, Suchard SJ, Nadler SG, Ford ML - PLoS ONE (2015)

Bottom Line: We previously showed that selective CD28 blockade with novel domain antibodies that leave CTLA-4-mediated coinhibitory signaling intact resulted in more profound attenuation of donor-reactive T cell responses and improved graft survival in a murine transplant model.Selective CD28 blockade was also associated with decreased ICOS expression on donor-reactive CD8+ T cell responses as compared to CTLA-4 Ig, but the functional importance of this reduced ICOS expression was not known.In this study, we created retrogenic donor-reactive CD8+ T cells that overexpress ICOS in order to determine whether reduced ICOS expression mechanistically underlies the increased efficacy of selective CD28 blockade in controlling graft-specific T cell responses as compared to conventional costimulation blockade with CTLA-4 Ig.

View Article: PubMed Central - PubMed

Affiliation: Emory Transplant Center and Department of Surgery, Emory University, Atlanta, GA 30322, United States of America.

ABSTRACT
Programmed T cell differentiation is critically influenced by the complement of costimulatory and coinhibitory signals transmitted during initial antigen encounter. We previously showed that selective CD28 blockade with novel domain antibodies that leave CTLA-4-mediated coinhibitory signaling intact resulted in more profound attenuation of donor-reactive T cell responses and improved graft survival in a murine transplant model. Selective CD28 blockade was also associated with decreased ICOS expression on donor-reactive CD8+ T cell responses as compared to CTLA-4 Ig, but the functional importance of this reduced ICOS expression was not known. In this study, we created retrogenic donor-reactive CD8+ T cells that overexpress ICOS in order to determine whether reduced ICOS expression mechanistically underlies the increased efficacy of selective CD28 blockade in controlling graft-specific T cell responses as compared to conventional costimulation blockade with CTLA-4 Ig. Results indicated that the ability of selective CD28 blockade to blunt donor-reactive CD8+ T cell expansion following transplantation was independent of its ability to inhibit ICOS expression. Furthermore, we have previously published that 2B4 coinhibitory signals are functionally important for controlling graft-specific CD8+ T cell responses in mice treated with CD28 blockade. Here we used a co-adoptive transfer approach to determine that 2B4 coinhibitory signals on antigen-specific CD8+ T cells function in a cell-intrinsic manner to limit ICOS expression in the setting of selective CD28 blockade.

No MeSH data available.


Related in: MedlinePlus

Upregulation of 2B4 (CD244) following selective CD28 blockade is independent of degree of ICOS expression.Naïve B6 animals were adoptively transferred with 106 congenically labeled ICOSrg Thy1.1+ OT-I T cells (or pMY Thy1.1+ OT-I controls) along with 106 Thy1.1+ CD4+ OT-II T cells and then challenged with an OVA-expressing skin graft. Groups of animals were left untreated or treated with anti-CD28 dAb. Animals were sacrificed at day 10 post transplant, and graft-draining LN T cells were analyzed for the expression of the magnitude of the CD8+ Thy1.1+ response. A, Representative flow cytometry plots depicting CD62L expression on control (left panel) or ICOSrg (right panel) Thy1.1+ CD8+ T cells in the treatment groups indicated. B, Summary data of CD62L expression (MFI) on control or ICOSrg Thy1.1+ CD8+ T cells (three independent experiments with a total of n = 6–9 animals/group). C, Representative flow cytometry plots depicting 2B4 expression on ICOSrg Thy1.1+ CD8+ T cells in the treatment groups indicated. B, Summary data of 4 expression (MFI) on ICOSrg Thy1.1+ CD8+ T cells (three independent experiments with a total of n = 6–9 animals/group). *p<0.05.
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pone.0130490.g005: Upregulation of 2B4 (CD244) following selective CD28 blockade is independent of degree of ICOS expression.Naïve B6 animals were adoptively transferred with 106 congenically labeled ICOSrg Thy1.1+ OT-I T cells (or pMY Thy1.1+ OT-I controls) along with 106 Thy1.1+ CD4+ OT-II T cells and then challenged with an OVA-expressing skin graft. Groups of animals were left untreated or treated with anti-CD28 dAb. Animals were sacrificed at day 10 post transplant, and graft-draining LN T cells were analyzed for the expression of the magnitude of the CD8+ Thy1.1+ response. A, Representative flow cytometry plots depicting CD62L expression on control (left panel) or ICOSrg (right panel) Thy1.1+ CD8+ T cells in the treatment groups indicated. B, Summary data of CD62L expression (MFI) on control or ICOSrg Thy1.1+ CD8+ T cells (three independent experiments with a total of n = 6–9 animals/group). C, Representative flow cytometry plots depicting 2B4 expression on ICOSrg Thy1.1+ CD8+ T cells in the treatment groups indicated. B, Summary data of 4 expression (MFI) on ICOSrg Thy1.1+ CD8+ T cells (three independent experiments with a total of n = 6–9 animals/group). *p<0.05.

Mentions: We next examined the cell surface phenotype of graft-specific pMY or ICOSrg cells in the presence or absence of selective CD28 blockade. As expected, anti-CD28 dAb treatment resulted an increase in the expression of CD62L on antigen-specific CD8+ T cells (Fig 5A and 5B), likely as a result of failure to downregulate CD62L during stunted activation and differentiation of these cells. Downregulation of CD62L was not rescued by overexpression of ICOS, as graft-specific ICOSrg cells similarly exhibited increased CD62L expression in the setting of anti-CD28 dAb as compared to untreated animals (Fig 5A and 5B).


Inhibition of Donor-Reactive CD8+ T Cell Responses by Selective CD28 Blockade Is Independent of Reduced ICOS Expression.

Liu D, Suchard SJ, Nadler SG, Ford ML - PLoS ONE (2015)

Upregulation of 2B4 (CD244) following selective CD28 blockade is independent of degree of ICOS expression.Naïve B6 animals were adoptively transferred with 106 congenically labeled ICOSrg Thy1.1+ OT-I T cells (or pMY Thy1.1+ OT-I controls) along with 106 Thy1.1+ CD4+ OT-II T cells and then challenged with an OVA-expressing skin graft. Groups of animals were left untreated or treated with anti-CD28 dAb. Animals were sacrificed at day 10 post transplant, and graft-draining LN T cells were analyzed for the expression of the magnitude of the CD8+ Thy1.1+ response. A, Representative flow cytometry plots depicting CD62L expression on control (left panel) or ICOSrg (right panel) Thy1.1+ CD8+ T cells in the treatment groups indicated. B, Summary data of CD62L expression (MFI) on control or ICOSrg Thy1.1+ CD8+ T cells (three independent experiments with a total of n = 6–9 animals/group). C, Representative flow cytometry plots depicting 2B4 expression on ICOSrg Thy1.1+ CD8+ T cells in the treatment groups indicated. B, Summary data of 4 expression (MFI) on ICOSrg Thy1.1+ CD8+ T cells (three independent experiments with a total of n = 6–9 animals/group). *p<0.05.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4476729&req=5

pone.0130490.g005: Upregulation of 2B4 (CD244) following selective CD28 blockade is independent of degree of ICOS expression.Naïve B6 animals were adoptively transferred with 106 congenically labeled ICOSrg Thy1.1+ OT-I T cells (or pMY Thy1.1+ OT-I controls) along with 106 Thy1.1+ CD4+ OT-II T cells and then challenged with an OVA-expressing skin graft. Groups of animals were left untreated or treated with anti-CD28 dAb. Animals were sacrificed at day 10 post transplant, and graft-draining LN T cells were analyzed for the expression of the magnitude of the CD8+ Thy1.1+ response. A, Representative flow cytometry plots depicting CD62L expression on control (left panel) or ICOSrg (right panel) Thy1.1+ CD8+ T cells in the treatment groups indicated. B, Summary data of CD62L expression (MFI) on control or ICOSrg Thy1.1+ CD8+ T cells (three independent experiments with a total of n = 6–9 animals/group). C, Representative flow cytometry plots depicting 2B4 expression on ICOSrg Thy1.1+ CD8+ T cells in the treatment groups indicated. B, Summary data of 4 expression (MFI) on ICOSrg Thy1.1+ CD8+ T cells (three independent experiments with a total of n = 6–9 animals/group). *p<0.05.
Mentions: We next examined the cell surface phenotype of graft-specific pMY or ICOSrg cells in the presence or absence of selective CD28 blockade. As expected, anti-CD28 dAb treatment resulted an increase in the expression of CD62L on antigen-specific CD8+ T cells (Fig 5A and 5B), likely as a result of failure to downregulate CD62L during stunted activation and differentiation of these cells. Downregulation of CD62L was not rescued by overexpression of ICOS, as graft-specific ICOSrg cells similarly exhibited increased CD62L expression in the setting of anti-CD28 dAb as compared to untreated animals (Fig 5A and 5B).

Bottom Line: We previously showed that selective CD28 blockade with novel domain antibodies that leave CTLA-4-mediated coinhibitory signaling intact resulted in more profound attenuation of donor-reactive T cell responses and improved graft survival in a murine transplant model.Selective CD28 blockade was also associated with decreased ICOS expression on donor-reactive CD8+ T cell responses as compared to CTLA-4 Ig, but the functional importance of this reduced ICOS expression was not known.In this study, we created retrogenic donor-reactive CD8+ T cells that overexpress ICOS in order to determine whether reduced ICOS expression mechanistically underlies the increased efficacy of selective CD28 blockade in controlling graft-specific T cell responses as compared to conventional costimulation blockade with CTLA-4 Ig.

View Article: PubMed Central - PubMed

Affiliation: Emory Transplant Center and Department of Surgery, Emory University, Atlanta, GA 30322, United States of America.

ABSTRACT
Programmed T cell differentiation is critically influenced by the complement of costimulatory and coinhibitory signals transmitted during initial antigen encounter. We previously showed that selective CD28 blockade with novel domain antibodies that leave CTLA-4-mediated coinhibitory signaling intact resulted in more profound attenuation of donor-reactive T cell responses and improved graft survival in a murine transplant model. Selective CD28 blockade was also associated with decreased ICOS expression on donor-reactive CD8+ T cell responses as compared to CTLA-4 Ig, but the functional importance of this reduced ICOS expression was not known. In this study, we created retrogenic donor-reactive CD8+ T cells that overexpress ICOS in order to determine whether reduced ICOS expression mechanistically underlies the increased efficacy of selective CD28 blockade in controlling graft-specific T cell responses as compared to conventional costimulation blockade with CTLA-4 Ig. Results indicated that the ability of selective CD28 blockade to blunt donor-reactive CD8+ T cell expansion following transplantation was independent of its ability to inhibit ICOS expression. Furthermore, we have previously published that 2B4 coinhibitory signals are functionally important for controlling graft-specific CD8+ T cell responses in mice treated with CD28 blockade. Here we used a co-adoptive transfer approach to determine that 2B4 coinhibitory signals on antigen-specific CD8+ T cells function in a cell-intrinsic manner to limit ICOS expression in the setting of selective CD28 blockade.

No MeSH data available.


Related in: MedlinePlus