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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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In vivo proliferation of graft-infiltrating T cells.Prior to transplantation, B6 mice were immunized with donor MHC DNA vaccines and/or treated with IL-2 regimen as described in Figure 1 legend. One week after receiving Balb/C islets under the kidney capsule, graft-infiltrating cells from B6 recipients were isolated to determine CD4+ and CD8+ T cell proliferation by BrdU uptakes. Histograms are shown after gating on CD4+ or CD8+ population. One representative histogram per group from three separate experiments is shown, and data are presented as mean ± SEM from three independent experiments. MHC II + IL-2 mainly suppressed CD4+ T cell proliferation while MHC I + IL-2/anti-IL-2 inhibited CD8+ T cell proliferation. The treatment protocol combining both suppressed both CD4+ and CD8+ cell proliferation, and further prevented T cell proliferation when rapamycin, at low doses, was additionally administered.
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pone-0008756-g005: In vivo proliferation of graft-infiltrating T cells.Prior to transplantation, B6 mice were immunized with donor MHC DNA vaccines and/or treated with IL-2 regimen as described in Figure 1 legend. One week after receiving Balb/C islets under the kidney capsule, graft-infiltrating cells from B6 recipients were isolated to determine CD4+ and CD8+ T cell proliferation by BrdU uptakes. Histograms are shown after gating on CD4+ or CD8+ population. One representative histogram per group from three separate experiments is shown, and data are presented as mean ± SEM from three independent experiments. MHC II + IL-2 mainly suppressed CD4+ T cell proliferation while MHC I + IL-2/anti-IL-2 inhibited CD8+ T cell proliferation. The treatment protocol combining both suppressed both CD4+ and CD8+ cell proliferation, and further prevented T cell proliferation when rapamycin, at low doses, was additionally administered.

Mentions: To study how donor MHC DNA vaccination and manipulating IL-2 suppress alloimmune responses, mice that were immunized and/or treated with IL-2 regimen prior to transplantation were sacrificed one week after islet transplantation, and graft-infiltrating cells from the kidney harboring islet allografts were isolated to measure T cell proliferation by BrdU uptakes. As shown in Figure 5, treatment with IL-2 or anti-IL-2 alone prior to transplantation did not alter the percentages of BrdU-positive cells in both CD4+ and CD8+ components one week after transplantation (BrdU+ in anti-IL-2 group: CD4: 40±2% vs. 41±3%, CD8: 42±3% vs. 43±4%; and BrdU+ in IL-2 group: CD4: 43±4% vs. 41±3%, CD8: 45±5% vs. 43±4%, all P>0.05). Neither did the vector control, MHC II alone, MHC I alone or MHC I + anti-IL-2 (data not shown in the figure). However, MHC I + IL-2/anti-IL-2 (A) pre-transplantation significantly suppressed CD8+, but not CD4+, T cell proliferation (CD4: 40±3% vs. 41±3%, P>0.05 and CD8: 30±3% vs. 43±4%, P<0.05), whereas MHC II + IL-2 (B) mainly inhibited CD4+ cell proliferation and only slightly inhibited CD8+ cell proliferation (CD4: 34±2% vs. 41±3%, P<0.05 and CD8: 37±3% vs. 43±4%, P>0.05). Moreover, treatments with both MHC II and MHC I plus IL-2 regimen (A+B) suppressed both CD4+ and CD8+ cell proliferation (CD4: 32±2% vs. 41±3%, P<0.05 and CD8: 23±2% vs. 43±4%, P<0.05). On the other hand, low dose of rapamycin alone post-transplantation without immunization pre-transplantation significantly suppressed CD4+ cell proliferation but only slightly inhibited CD8+ cell proliferation (CD4: 22±3% vs. 41±3%, P<0.05 and CD8: 35±3% vs. 43±4%, P = 0.056). Importantly, the combined treatments with MHC I/II vaccination, IL-2 regimen and rapamycin (A+ B+ Rapa) largely prevented both CD4+ and CD8+ cell proliferation (CD4: 9±1% vs. 41±3%, P<0.05 and CD8: 8±1% vs. 43±4%, P<0.05, Figure 5). Taken together, MHC I + IL-2/anti-IL-2 pre-transplantation mainly suppressed CD8+ T cell proliferation in the grafts, whereas MHC II + IL-2 pre-transplantation mainly inhibited CD4+ T cell proliferation. The measures combining both suppressed both CD4+ and CD8+ T cell turnover and largely prevented T cell proliferation when rapamycin, at low doses, was also administered post-transplantation.


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)

In vivo proliferation of graft-infiltrating T cells.Prior to transplantation, B6 mice were immunized with donor MHC DNA vaccines and/or treated with IL-2 regimen as described in Figure 1 legend. One week after receiving Balb/C islets under the kidney capsule, graft-infiltrating cells from B6 recipients were isolated to determine CD4+ and CD8+ T cell proliferation by BrdU uptakes. Histograms are shown after gating on CD4+ or CD8+ population. One representative histogram per group from three separate experiments is shown, and data are presented as mean ± SEM from three independent experiments. MHC II + IL-2 mainly suppressed CD4+ T cell proliferation while MHC I + IL-2/anti-IL-2 inhibited CD8+ T cell proliferation. The treatment protocol combining both suppressed both CD4+ and CD8+ cell proliferation, and further prevented T cell proliferation when rapamycin, at low doses, was additionally administered.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2807454&req=5

pone-0008756-g005: In vivo proliferation of graft-infiltrating T cells.Prior to transplantation, B6 mice were immunized with donor MHC DNA vaccines and/or treated with IL-2 regimen as described in Figure 1 legend. One week after receiving Balb/C islets under the kidney capsule, graft-infiltrating cells from B6 recipients were isolated to determine CD4+ and CD8+ T cell proliferation by BrdU uptakes. Histograms are shown after gating on CD4+ or CD8+ population. One representative histogram per group from three separate experiments is shown, and data are presented as mean ± SEM from three independent experiments. MHC II + IL-2 mainly suppressed CD4+ T cell proliferation while MHC I + IL-2/anti-IL-2 inhibited CD8+ T cell proliferation. The treatment protocol combining both suppressed both CD4+ and CD8+ cell proliferation, and further prevented T cell proliferation when rapamycin, at low doses, was additionally administered.
Mentions: To study how donor MHC DNA vaccination and manipulating IL-2 suppress alloimmune responses, mice that were immunized and/or treated with IL-2 regimen prior to transplantation were sacrificed one week after islet transplantation, and graft-infiltrating cells from the kidney harboring islet allografts were isolated to measure T cell proliferation by BrdU uptakes. As shown in Figure 5, treatment with IL-2 or anti-IL-2 alone prior to transplantation did not alter the percentages of BrdU-positive cells in both CD4+ and CD8+ components one week after transplantation (BrdU+ in anti-IL-2 group: CD4: 40±2% vs. 41±3%, CD8: 42±3% vs. 43±4%; and BrdU+ in IL-2 group: CD4: 43±4% vs. 41±3%, CD8: 45±5% vs. 43±4%, all P>0.05). Neither did the vector control, MHC II alone, MHC I alone or MHC I + anti-IL-2 (data not shown in the figure). However, MHC I + IL-2/anti-IL-2 (A) pre-transplantation significantly suppressed CD8+, but not CD4+, T cell proliferation (CD4: 40±3% vs. 41±3%, P>0.05 and CD8: 30±3% vs. 43±4%, P<0.05), whereas MHC II + IL-2 (B) mainly inhibited CD4+ cell proliferation and only slightly inhibited CD8+ cell proliferation (CD4: 34±2% vs. 41±3%, P<0.05 and CD8: 37±3% vs. 43±4%, P>0.05). Moreover, treatments with both MHC II and MHC I plus IL-2 regimen (A+B) suppressed both CD4+ and CD8+ cell proliferation (CD4: 32±2% vs. 41±3%, P<0.05 and CD8: 23±2% vs. 43±4%, P<0.05). On the other hand, low dose of rapamycin alone post-transplantation without immunization pre-transplantation significantly suppressed CD4+ cell proliferation but only slightly inhibited CD8+ cell proliferation (CD4: 22±3% vs. 41±3%, P<0.05 and CD8: 35±3% vs. 43±4%, P = 0.056). Importantly, the combined treatments with MHC I/II vaccination, IL-2 regimen and rapamycin (A+ B+ Rapa) largely prevented both CD4+ and CD8+ cell proliferation (CD4: 9±1% vs. 41±3%, P<0.05 and CD8: 8±1% vs. 43±4%, P<0.05, Figure 5). Taken together, MHC I + IL-2/anti-IL-2 pre-transplantation mainly suppressed CD8+ T cell proliferation in the grafts, whereas MHC II + IL-2 pre-transplantation mainly inhibited CD4+ T cell proliferation. The measures combining both suppressed both CD4+ and CD8+ T cell turnover and largely prevented T cell proliferation when rapamycin, at low doses, was also administered post-transplantation.

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