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Manipulating IL-2 availability amid presentation of donor MHC antigens suppresses murine alloimmune responses by inducing regulatory T cells.

Zhang S, Dai H, Wan N, Moore Y, Dai Z - PLoS ONE (2010)

Bottom Line: Importantly, MHCII + IL-2 induced FoxP3+ Treg cells in both spleens and grafts and suppressed graft-infiltrating CD4+ cell proliferation, whereas MHCI + IL-2/anti-IL-2 mainly inhibited graft-infiltrating CD8+ cell proliferation and donor-specific CTL activity.The combined protocol plus rapamycin treatment further reduced both CD4+ and CD8+ T cell proliferation as well as donor-specific CTL activity but spared FoxP3+ Treg cells.Depleting CD25+ Treg cells or adoptive transfer of pre-sensitized CD8+ T cells abolished this long-term allograft survival.

View Article: PubMed Central - PubMed

Affiliation: Center for Biomedical Research, University of Texas Health Science Center, Tyler, Texas, United States of America.

ABSTRACT

Background: Major histocompatibility complex (MHC) antigens are important for alloimmune responses as well as immune tolerance. Previous studies have shown that presentation of donor MHC antigens by donor-specific transfusion prior to or upon transplantation promotes transplant tolerance induced by other agents. However, it is unclear whether presentation of donor MHC antigens by DNA vaccination induces long-term allograft survival.

Methodology/principal findings: We investigated whether presentation of MHC class-II and/or class-I donor antigens by DNA vaccination suppresses alloimmune responses and promotes long-term allograft acceptance. We initially found that presentation of both MHC donor antigens by DNA vaccination itself prior to transplantation fails to significantly prolong islet allograft survival in otherwise untreated mice. However, islet allograft survival was significantly prolonged when MHC class-II DNA vaccination was accompanied with IL-2 administration (MHCII + IL-2) while MHC class-I DNA vaccination was followed by IL-2 and subsequent neutralizing anti-IL-2 treatments (MHCI + IL-2/anti-IL-2). Especially, this protocol promoted long-term allograft survival in the majority of recipients (57%) when combined with low doses of rapamycin post-transplantation. Importantly, MHCII + IL-2 induced FoxP3+ Treg cells in both spleens and grafts and suppressed graft-infiltrating CD4+ cell proliferation, whereas MHCI + IL-2/anti-IL-2 mainly inhibited graft-infiltrating CD8+ cell proliferation and donor-specific CTL activity. The combined protocol plus rapamycin treatment further reduced both CD4+ and CD8+ T cell proliferation as well as donor-specific CTL activity but spared FoxP3+ Treg cells. Depleting CD25+ Treg cells or adoptive transfer of pre-sensitized CD8+ T cells abolished this long-term allograft survival.

Conclusions/significance: Manipulating IL-2 availability during presentation of MHC class-II and class-I donor antigens by DNA vaccination pre-transplantation induces Treg cells, suppresses alloimmune responses and promotes long-term allograft survival.

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Related in: MedlinePlus

Donor MHC DNA vaccination and administration of IL-2 regimen prior to transplantation promote long-term islet allograft survival.Prior to transplantation, B6 mice were untreated (□, n = 10) or treated with neutralizing anti-IL-2 (◊, n = 6) alone, recombinant IL-2 alone (υ, n = 8), donor MHC class-I DNA vaccination plus both IL-2 and subsequent anti-IL-2 (MHC I + IL-2/anti-IL-2: A) (○, n = 6), donor MHC class-II DNA vaccination plus IL-2 (MHC II + IL-2: B) (λ, n = 7), or both MHC I and MHC II vaccination plus IL-2 regimen (A + B) (σ, n = 7). In some groups, rapamycin control mice (Rapa) (▵, n = 8) or mice treated with both MHC vaccinations and IL-2 regimen (A + B + Rapa) (ν, n = 7) or both vaccinations without IL-2 (MHC I + MHC II + Rapa) (⊕, n = 6) received low doses of rapamycin post-transplantation. (A). Islet allograft rejection was observed. (B). H&E staining on kidney sections at the time of rejection or 100 days after transplantation. (C). Immunofluorescence staining on muscular frozen sections for the expression of donor MHC I (H-2Kd) or MHC II (I-Ad) three days after donor MHC DNA vaccination in a recipient. One representative of three independent experiments is shown.
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pone-0008756-g002: Donor MHC DNA vaccination and administration of IL-2 regimen prior to transplantation promote long-term islet allograft survival.Prior to transplantation, B6 mice were untreated (□, n = 10) or treated with neutralizing anti-IL-2 (◊, n = 6) alone, recombinant IL-2 alone (υ, n = 8), donor MHC class-I DNA vaccination plus both IL-2 and subsequent anti-IL-2 (MHC I + IL-2/anti-IL-2: A) (○, n = 6), donor MHC class-II DNA vaccination plus IL-2 (MHC II + IL-2: B) (λ, n = 7), or both MHC I and MHC II vaccination plus IL-2 regimen (A + B) (σ, n = 7). In some groups, rapamycin control mice (Rapa) (▵, n = 8) or mice treated with both MHC vaccinations and IL-2 regimen (A + B + Rapa) (ν, n = 7) or both vaccinations without IL-2 (MHC I + MHC II + Rapa) (⊕, n = 6) received low doses of rapamycin post-transplantation. (A). Islet allograft rejection was observed. (B). H&E staining on kidney sections at the time of rejection or 100 days after transplantation. (C). Immunofluorescence staining on muscular frozen sections for the expression of donor MHC I (H-2Kd) or MHC II (I-Ad) three days after donor MHC DNA vaccination in a recipient. One representative of three independent experiments is shown.

Mentions: To study whether presentation of both MHC class-II and class-I donor antigens by DNA vaccination promotes long-term allograft survival, B6 mice were immunized with MHC class-II and/or class-I donor antigens by DNA vaccines and treated with recombinant IL-2 or neutralizing anti-IL-2 Ab, as described in the Methods section and Figure 1, before they received islet allografts from Balb/C donors. As shown in Figure 2A, neither MHC I + IL-2/anti-IL-2 nor MHC II + IL-2 treatment significantly prolonged islet allograft survival compared to control group (median survival time, MST = 18 vs. 16 days or 19 vs. 16 days, both P>0.05). Also as controls, neither anti-IL-2 alone nor IL-2 alone prior to transplantation altered islet allograft survival (MST = 15 vs. 16 days or 14 vs. 16 days, both P>0.05). Treatments with isotype Ab for anti-IL-2 or with MHC I and/or MHC II immunization but without IL-2 did not affect allograft survival (data not shown in the figure). However, the protocol that combined MHC I + IL-2/anti-IL-2 and subsequent MHC II + IL-2 treatments (A + B) significantly prolonged islet allograft survival compared to control group (MST = 31 vs. 16 days, P<0.05). More importantly, this combined protocol induced long-term islet allograft survival in the majority of recipients (57%) when rapamycin, at low doses, was also administered after transplantation (A+ B+ Rapa). On the other hand, treatments with the same doses of rapamycin failed to induce long-term islet allograft survival in the presence of either MHC I + IL-2/anti-IL-2 (A) or MHC II + IL-2 B (data not shown in the figure). Although rapamycin plus both MHC I and MHC II vaccination without the IL-2 regimen (MHC I + MHC II + Rapa) significantly prolonged allograft survival compared to control group (MST = 40 vs. 16 days, P<0.05), they did not induce long-term allograft survival and were much less effective than the same treatments plus IL-2 regimen (A+ B+ Rapa) (MST = 40 vs. 112 days, P<0.05), suggesting that IL-2 regimen in this treatment protocol is essential for long-term allograft survival. H&E staining on sections of the kidney confirmed cellular infiltration in and around islet grafts in the control group (Control) and the group treated with MHC I + IL-2/anti-IL-2 plus MHC II + IL-2 (A + B) but not the group treated with A + B + Rapa (Figure 2B) that achieved long-term allograft survival. Moreover, tissue immunofluorescence staining also confirmed the expression of donor MHC class-II (I-Ad) and MHC class-I (H-2Kd) molecules three days after DNA vaccination (Figure 2C).


Manipulating IL-2 availability amid presentation of donor MHC antigens suppresses murine alloimmune responses by inducing regulatory T cells.

Zhang S, Dai H, Wan N, Moore Y, Dai Z - PLoS ONE (2010)

Donor MHC DNA vaccination and administration of IL-2 regimen prior to transplantation promote long-term islet allograft survival.Prior to transplantation, B6 mice were untreated (□, n = 10) or treated with neutralizing anti-IL-2 (◊, n = 6) alone, recombinant IL-2 alone (υ, n = 8), donor MHC class-I DNA vaccination plus both IL-2 and subsequent anti-IL-2 (MHC I + IL-2/anti-IL-2: A) (○, n = 6), donor MHC class-II DNA vaccination plus IL-2 (MHC II + IL-2: B) (λ, n = 7), or both MHC I and MHC II vaccination plus IL-2 regimen (A + B) (σ, n = 7). In some groups, rapamycin control mice (Rapa) (▵, n = 8) or mice treated with both MHC vaccinations and IL-2 regimen (A + B + Rapa) (ν, n = 7) or both vaccinations without IL-2 (MHC I + MHC II + Rapa) (⊕, n = 6) received low doses of rapamycin post-transplantation. (A). Islet allograft rejection was observed. (B). H&E staining on kidney sections at the time of rejection or 100 days after transplantation. (C). Immunofluorescence staining on muscular frozen sections for the expression of donor MHC I (H-2Kd) or MHC II (I-Ad) three days after donor MHC DNA vaccination in a recipient. One representative of three independent experiments is shown.
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Related In: Results  -  Collection

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pone-0008756-g002: Donor MHC DNA vaccination and administration of IL-2 regimen prior to transplantation promote long-term islet allograft survival.Prior to transplantation, B6 mice were untreated (□, n = 10) or treated with neutralizing anti-IL-2 (◊, n = 6) alone, recombinant IL-2 alone (υ, n = 8), donor MHC class-I DNA vaccination plus both IL-2 and subsequent anti-IL-2 (MHC I + IL-2/anti-IL-2: A) (○, n = 6), donor MHC class-II DNA vaccination plus IL-2 (MHC II + IL-2: B) (λ, n = 7), or both MHC I and MHC II vaccination plus IL-2 regimen (A + B) (σ, n = 7). In some groups, rapamycin control mice (Rapa) (▵, n = 8) or mice treated with both MHC vaccinations and IL-2 regimen (A + B + Rapa) (ν, n = 7) or both vaccinations without IL-2 (MHC I + MHC II + Rapa) (⊕, n = 6) received low doses of rapamycin post-transplantation. (A). Islet allograft rejection was observed. (B). H&E staining on kidney sections at the time of rejection or 100 days after transplantation. (C). Immunofluorescence staining on muscular frozen sections for the expression of donor MHC I (H-2Kd) or MHC II (I-Ad) three days after donor MHC DNA vaccination in a recipient. One representative of three independent experiments is shown.
Mentions: To study whether presentation of both MHC class-II and class-I donor antigens by DNA vaccination promotes long-term allograft survival, B6 mice were immunized with MHC class-II and/or class-I donor antigens by DNA vaccines and treated with recombinant IL-2 or neutralizing anti-IL-2 Ab, as described in the Methods section and Figure 1, before they received islet allografts from Balb/C donors. As shown in Figure 2A, neither MHC I + IL-2/anti-IL-2 nor MHC II + IL-2 treatment significantly prolonged islet allograft survival compared to control group (median survival time, MST = 18 vs. 16 days or 19 vs. 16 days, both P>0.05). Also as controls, neither anti-IL-2 alone nor IL-2 alone prior to transplantation altered islet allograft survival (MST = 15 vs. 16 days or 14 vs. 16 days, both P>0.05). Treatments with isotype Ab for anti-IL-2 or with MHC I and/or MHC II immunization but without IL-2 did not affect allograft survival (data not shown in the figure). However, the protocol that combined MHC I + IL-2/anti-IL-2 and subsequent MHC II + IL-2 treatments (A + B) significantly prolonged islet allograft survival compared to control group (MST = 31 vs. 16 days, P<0.05). More importantly, this combined protocol induced long-term islet allograft survival in the majority of recipients (57%) when rapamycin, at low doses, was also administered after transplantation (A+ B+ Rapa). On the other hand, treatments with the same doses of rapamycin failed to induce long-term islet allograft survival in the presence of either MHC I + IL-2/anti-IL-2 (A) or MHC II + IL-2 B (data not shown in the figure). Although rapamycin plus both MHC I and MHC II vaccination without the IL-2 regimen (MHC I + MHC II + Rapa) significantly prolonged allograft survival compared to control group (MST = 40 vs. 16 days, P<0.05), they did not induce long-term allograft survival and were much less effective than the same treatments plus IL-2 regimen (A+ B+ Rapa) (MST = 40 vs. 112 days, P<0.05), suggesting that IL-2 regimen in this treatment protocol is essential for long-term allograft survival. H&E staining on sections of the kidney confirmed cellular infiltration in and around islet grafts in the control group (Control) and the group treated with MHC I + IL-2/anti-IL-2 plus MHC II + IL-2 (A + B) but not the group treated with A + B + Rapa (Figure 2B) that achieved long-term allograft survival. Moreover, tissue immunofluorescence staining also confirmed the expression of donor MHC class-II (I-Ad) and MHC class-I (H-2Kd) molecules three days after DNA vaccination (Figure 2C).

Bottom Line: Importantly, MHCII + IL-2 induced FoxP3+ Treg cells in both spleens and grafts and suppressed graft-infiltrating CD4+ cell proliferation, whereas MHCI + IL-2/anti-IL-2 mainly inhibited graft-infiltrating CD8+ cell proliferation and donor-specific CTL activity.The combined protocol plus rapamycin treatment further reduced both CD4+ and CD8+ T cell proliferation as well as donor-specific CTL activity but spared FoxP3+ Treg cells.Depleting CD25+ Treg cells or adoptive transfer of pre-sensitized CD8+ T cells abolished this long-term allograft survival.

View Article: PubMed Central - PubMed

Affiliation: Center for Biomedical Research, University of Texas Health Science Center, Tyler, Texas, United States of America.

ABSTRACT

Background: Major histocompatibility complex (MHC) antigens are important for alloimmune responses as well as immune tolerance. Previous studies have shown that presentation of donor MHC antigens by donor-specific transfusion prior to or upon transplantation promotes transplant tolerance induced by other agents. However, it is unclear whether presentation of donor MHC antigens by DNA vaccination induces long-term allograft survival.

Methodology/principal findings: We investigated whether presentation of MHC class-II and/or class-I donor antigens by DNA vaccination suppresses alloimmune responses and promotes long-term allograft acceptance. We initially found that presentation of both MHC donor antigens by DNA vaccination itself prior to transplantation fails to significantly prolong islet allograft survival in otherwise untreated mice. However, islet allograft survival was significantly prolonged when MHC class-II DNA vaccination was accompanied with IL-2 administration (MHCII + IL-2) while MHC class-I DNA vaccination was followed by IL-2 and subsequent neutralizing anti-IL-2 treatments (MHCI + IL-2/anti-IL-2). Especially, this protocol promoted long-term allograft survival in the majority of recipients (57%) when combined with low doses of rapamycin post-transplantation. Importantly, MHCII + IL-2 induced FoxP3+ Treg cells in both spleens and grafts and suppressed graft-infiltrating CD4+ cell proliferation, whereas MHCI + IL-2/anti-IL-2 mainly inhibited graft-infiltrating CD8+ cell proliferation and donor-specific CTL activity. The combined protocol plus rapamycin treatment further reduced both CD4+ and CD8+ T cell proliferation as well as donor-specific CTL activity but spared FoxP3+ Treg cells. Depleting CD25+ Treg cells or adoptive transfer of pre-sensitized CD8+ T cells abolished this long-term allograft survival.

Conclusions/significance: Manipulating IL-2 availability during presentation of MHC class-II and class-I donor antigens by DNA vaccination pre-transplantation induces Treg cells, suppresses alloimmune responses and promotes long-term allograft survival.

Show MeSH
Related in: MedlinePlus