CD4+CD25HiFoxP3+ regulatory T cells in long-term cardiac xenotransplantation

Avneesh K. Singh; Joshua L. Chan; Caleb N. Seavey; Philip C. Corcoran; Robert F. Hoyt; Billeta G.T. Lewis; Marvin L. Thomas; David L. Ayares; Keith A. Horvath; Muhammad M. Mohiuddin

doi:10.1111/xen.12379

CD4+CD25^HiFoxP3+ regulatory T cells in long-term cardiac xenotransplantation

Avneesh K. Singh, Joshua L. Chan, Caleb N. Seavey, Philip C. Corcoran, Robert F. Hoyt, Billeta G.T. Lewis, Marvin L. Thomas, David L. Ayares, Keith A. Horvath, Muhammad M. Mohiuddin

Research output: Contribution to journal › Article › peer-review

10 Scopus citations

Abstract

Background: CD4+CD25^HiFoxP3+ T (Treg) cells are a small subset of CD4+ T cells that have been shown to exhibit immunoregulatory function. Although the absolute number of Treg cells in peripheral blood lymphocytes (PBL) is very small, they play an important role in suppressing immune reactivity. Several studies have demonstrated that the number of Treg cells, rather than their intrinsic suppressive capacity, may contribute to determining the long-term fate of transplanted grafts. In this study, we analyzed Treg cells in PBL of long-term baboon recipients who have received genetically modified cardiac xenografts from pig donors. Methods: Heterotopic cardiac xenotransplantation was performed on baboons using hearts obtained from GTKO.hCD46 (n = 8) and GTKO.hCD46.TBM (n = 5) genetically modified pigs. Modified immunosuppression regimen included antithymocyte globulin (ATG), anti-CD20, mycophenolate mofetil (MMF), cobra venom factor (CVF), and costimulation blockade (anti-CD154/anti-CD40 monoclonal antibody). FACS analysis was performed on PBLs labeled with anti-human CD4, CD25, and FoxP3 monoclonal antibodies (mAb) to analyze the percentage of Treg cells in six baboons that survived longer than 2 months (range: 42-945 days) after receiving a pig cardiac xenograft. Results: Total WBC count was low due to immunosuppression in baboons who received cardiac xenograft from GTKO.hCD46 and GTKO.hCD46.hTBM donor pigs. However, absolute numbers of CD4+CD25^HiFoxP3 Treg cells in PBLs of long-term xenograft cardiac xenograft surviving baboon recipients were found to be increased (15.13 ± 1.50 vs 7.38 ± 2.92; P <.018) as compared to naïve or pre-transplant baboons. Xenograft rejection in these animals was correlated with decreased numbers of regulatory T cells. Conclusion: Our results suggest that regulatory T (Treg) cells may contribute to preventing or delaying xenograft rejection by controlling the activation and expansion of donor-reactive T cells, thereby masking the antidonor immune response, leading to long-term survival of cardiac xenografts.

Original language	English (US)
Article number	e12379
Journal	Xenotransplantation
Volume	25
Issue number	2
DOIs	https://doi.org/10.1111/xen.12379
State	Published - Mar 1 2018
Externally published	Yes

Keywords

immunosuppression
regulatory T lymphocytes
xenograft rejection
xenotransplantation

ASJC Scopus subject areas

Immunology
Transplantation

Access to Document

10.1111/xen.12379

Cite this

@article{4b6aebb2ab454494ba87636fbd007ed1,

title = "CD4+CD25HiFoxP3+ regulatory T cells in long-term cardiac xenotransplantation",

abstract = "Background: CD4+CD25HiFoxP3+ T (Treg) cells are a small subset of CD4+ T cells that have been shown to exhibit immunoregulatory function. Although the absolute number of Treg cells in peripheral blood lymphocytes (PBL) is very small, they play an important role in suppressing immune reactivity. Several studies have demonstrated that the number of Treg cells, rather than their intrinsic suppressive capacity, may contribute to determining the long-term fate of transplanted grafts. In this study, we analyzed Treg cells in PBL of long-term baboon recipients who have received genetically modified cardiac xenografts from pig donors. Methods: Heterotopic cardiac xenotransplantation was performed on baboons using hearts obtained from GTKO.hCD46 (n = 8) and GTKO.hCD46.TBM (n = 5) genetically modified pigs. Modified immunosuppression regimen included antithymocyte globulin (ATG), anti-CD20, mycophenolate mofetil (MMF), cobra venom factor (CVF), and costimulation blockade (anti-CD154/anti-CD40 monoclonal antibody). FACS analysis was performed on PBLs labeled with anti-human CD4, CD25, and FoxP3 monoclonal antibodies (mAb) to analyze the percentage of Treg cells in six baboons that survived longer than 2 months (range: 42-945 days) after receiving a pig cardiac xenograft. Results: Total WBC count was low due to immunosuppression in baboons who received cardiac xenograft from GTKO.hCD46 and GTKO.hCD46.hTBM donor pigs. However, absolute numbers of CD4+CD25HiFoxP3 Treg cells in PBLs of long-term xenograft cardiac xenograft surviving baboon recipients were found to be increased (15.13 ± 1.50 vs 7.38 ± 2.92; P <.018) as compared to na{\"i}ve or pre-transplant baboons. Xenograft rejection in these animals was correlated with decreased numbers of regulatory T cells. Conclusion: Our results suggest that regulatory T (Treg) cells may contribute to preventing or delaying xenograft rejection by controlling the activation and expansion of donor-reactive T cells, thereby masking the antidonor immune response, leading to long-term survival of cardiac xenografts.",

keywords = "immunosuppression, regulatory T lymphocytes, xenograft rejection, xenotransplantation",

author = "Singh, {Avneesh K.} and Chan, {Joshua L.} and Seavey, {Caleb N.} and Corcoran, {Philip C.} and Hoyt, {Robert F.} and Lewis, {Billeta G.T.} and Thomas, {Marvin L.} and Ayares, {David L.} and Horvath, {Keith A.} and Mohiuddin, {Muhammad M.}",

note = "Funding Information: DLA is an employee of Revivicor, Inc. None of the remaining authors have any conflict of interests or relevant financial relationships with an external or commercial entity to disclose. Work at the NHLBI was funded through contract HHSN268201300001C and gift funds from Revivicor, Inc. No external or commercial entities were involved in this study{\textquoteright}s design, analysis, or interpretation of data. MMM had access to all of the data in this study and takes complete responsibility for the integrity of the data and the accuracy of the data analysis. The decision to write this report and to submit it for publication was made Publisher Copyright: {\textcopyright} 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.",

year = "2018",

month = mar,

day = "1",

doi = "10.1111/xen.12379",

language = "English (US)",

volume = "25",

journal = "Xenotransplantation",

issn = "0908-665X",

publisher = "Wiley-Blackwell",

number = "2",

}

TY - JOUR

T1 - CD4+CD25HiFoxP3+ regulatory T cells in long-term cardiac xenotransplantation

AU - Singh, Avneesh K.

AU - Chan, Joshua L.

AU - Seavey, Caleb N.

AU - Corcoran, Philip C.

AU - Hoyt, Robert F.

AU - Lewis, Billeta G.T.

AU - Thomas, Marvin L.

AU - Ayares, David L.

AU - Horvath, Keith A.

AU - Mohiuddin, Muhammad M.

N1 - Funding Information: DLA is an employee of Revivicor, Inc. None of the remaining authors have any conflict of interests or relevant financial relationships with an external or commercial entity to disclose. Work at the NHLBI was funded through contract HHSN268201300001C and gift funds from Revivicor, Inc. No external or commercial entities were involved in this study’s design, analysis, or interpretation of data. MMM had access to all of the data in this study and takes complete responsibility for the integrity of the data and the accuracy of the data analysis. The decision to write this report and to submit it for publication was made Publisher Copyright: © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

PY - 2018/3/1

Y1 - 2018/3/1

N2 - Background: CD4+CD25HiFoxP3+ T (Treg) cells are a small subset of CD4+ T cells that have been shown to exhibit immunoregulatory function. Although the absolute number of Treg cells in peripheral blood lymphocytes (PBL) is very small, they play an important role in suppressing immune reactivity. Several studies have demonstrated that the number of Treg cells, rather than their intrinsic suppressive capacity, may contribute to determining the long-term fate of transplanted grafts. In this study, we analyzed Treg cells in PBL of long-term baboon recipients who have received genetically modified cardiac xenografts from pig donors. Methods: Heterotopic cardiac xenotransplantation was performed on baboons using hearts obtained from GTKO.hCD46 (n = 8) and GTKO.hCD46.TBM (n = 5) genetically modified pigs. Modified immunosuppression regimen included antithymocyte globulin (ATG), anti-CD20, mycophenolate mofetil (MMF), cobra venom factor (CVF), and costimulation blockade (anti-CD154/anti-CD40 monoclonal antibody). FACS analysis was performed on PBLs labeled with anti-human CD4, CD25, and FoxP3 monoclonal antibodies (mAb) to analyze the percentage of Treg cells in six baboons that survived longer than 2 months (range: 42-945 days) after receiving a pig cardiac xenograft. Results: Total WBC count was low due to immunosuppression in baboons who received cardiac xenograft from GTKO.hCD46 and GTKO.hCD46.hTBM donor pigs. However, absolute numbers of CD4+CD25HiFoxP3 Treg cells in PBLs of long-term xenograft cardiac xenograft surviving baboon recipients were found to be increased (15.13 ± 1.50 vs 7.38 ± 2.92; P <.018) as compared to naïve or pre-transplant baboons. Xenograft rejection in these animals was correlated with decreased numbers of regulatory T cells. Conclusion: Our results suggest that regulatory T (Treg) cells may contribute to preventing or delaying xenograft rejection by controlling the activation and expansion of donor-reactive T cells, thereby masking the antidonor immune response, leading to long-term survival of cardiac xenografts.

AB - Background: CD4+CD25HiFoxP3+ T (Treg) cells are a small subset of CD4+ T cells that have been shown to exhibit immunoregulatory function. Although the absolute number of Treg cells in peripheral blood lymphocytes (PBL) is very small, they play an important role in suppressing immune reactivity. Several studies have demonstrated that the number of Treg cells, rather than their intrinsic suppressive capacity, may contribute to determining the long-term fate of transplanted grafts. In this study, we analyzed Treg cells in PBL of long-term baboon recipients who have received genetically modified cardiac xenografts from pig donors. Methods: Heterotopic cardiac xenotransplantation was performed on baboons using hearts obtained from GTKO.hCD46 (n = 8) and GTKO.hCD46.TBM (n = 5) genetically modified pigs. Modified immunosuppression regimen included antithymocyte globulin (ATG), anti-CD20, mycophenolate mofetil (MMF), cobra venom factor (CVF), and costimulation blockade (anti-CD154/anti-CD40 monoclonal antibody). FACS analysis was performed on PBLs labeled with anti-human CD4, CD25, and FoxP3 monoclonal antibodies (mAb) to analyze the percentage of Treg cells in six baboons that survived longer than 2 months (range: 42-945 days) after receiving a pig cardiac xenograft. Results: Total WBC count was low due to immunosuppression in baboons who received cardiac xenograft from GTKO.hCD46 and GTKO.hCD46.hTBM donor pigs. However, absolute numbers of CD4+CD25HiFoxP3 Treg cells in PBLs of long-term xenograft cardiac xenograft surviving baboon recipients were found to be increased (15.13 ± 1.50 vs 7.38 ± 2.92; P <.018) as compared to naïve or pre-transplant baboons. Xenograft rejection in these animals was correlated with decreased numbers of regulatory T cells. Conclusion: Our results suggest that regulatory T (Treg) cells may contribute to preventing or delaying xenograft rejection by controlling the activation and expansion of donor-reactive T cells, thereby masking the antidonor immune response, leading to long-term survival of cardiac xenografts.

KW - immunosuppression

KW - regulatory T lymphocytes

KW - xenograft rejection

KW - xenotransplantation

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U2 - 10.1111/xen.12379

DO - 10.1111/xen.12379

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SN - 0908-665X

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