Regulatory T cells contribute to the protective effect of ischemic preconditioning in the kidney
2010; Elsevier BV; Volume: 77; Issue: 9 Linguagem: Inglês
10.1038/ki.2010.12
ISSN1523-1755
AutoresGilbert R. Kinsey, Liping Huang, Amy L. Vergis, Li L, Mark D. Okusa,
Tópico(s)Immune Response and Inflammation
ResumoReperfusion following ischemia is associated with acute kidney injury and inflammation. Using a mouse model, we exposed the kidney to a nonlethal period of ischemia, rendering it refractory to future ischemia-induced dysfunction. This ischemic preconditioning is partially mediated by Treg lymphocytes that suppress immune responses. We found that this maneuver significantly inhibited the accumulation of neutrophils and macrophages, tubular necrosis, and loss of kidney function caused by a subsequent ischemia/reperfusion injury 1 week later. The initial ischemia/reperfusion caused a significant increase in CD4+CD25+FoxP3+ and CD4+CD25+IL-10+ Treg cells within the kidney at 7 days of reperfusion. Treatment of preconditioned mice with a Treg cell–depleting antibody (PC61) reversed the effect of preconditioning on kidney neutrophil accumulation and partially inhibited the functional and histological protection of preconditioning. Adoptive transfer of Treg cells in naive mice, before ischemia/reperfusion, mimicked the protective and anti-inflammatory effects of ischemic preconditioning on the kidney. These studies highlight the role of Treg cells in ischemic preconditioning. Reperfusion following ischemia is associated with acute kidney injury and inflammation. Using a mouse model, we exposed the kidney to a nonlethal period of ischemia, rendering it refractory to future ischemia-induced dysfunction. This ischemic preconditioning is partially mediated by Treg lymphocytes that suppress immune responses. We found that this maneuver significantly inhibited the accumulation of neutrophils and macrophages, tubular necrosis, and loss of kidney function caused by a subsequent ischemia/reperfusion injury 1 week later. The initial ischemia/reperfusion caused a significant increase in CD4+CD25+FoxP3+ and CD4+CD25+IL-10+ Treg cells within the kidney at 7 days of reperfusion. Treatment of preconditioned mice with a Treg cell–depleting antibody (PC61) reversed the effect of preconditioning on kidney neutrophil accumulation and partially inhibited the functional and histological protection of preconditioning. Adoptive transfer of Treg cells in naive mice, before ischemia/reperfusion, mimicked the protective and anti-inflammatory effects of ischemic preconditioning on the kidney. These studies highlight the role of Treg cells in ischemic preconditioning. Acute kidney injury is associated with high morbidity and mortality and can predispose individuals to end-stage renal disease.1.Ishani A. Xue J.L. Himmelfarb J. et al.Acute kidney injury increases risk of ESRD among elderly.J Am Soc Nephrol. 2009; 20: 223-228Crossref PubMed Scopus (809) Google Scholar Ischemia/reperfusion injury (IRI) is a major cause of acute kidney injury. Although the pathogenesis of IRI is multifactorial, inflammation in the post-ischemic kidney has been well established as a detrimental process in the pathogenesis of kidney IRI.2.Burne M.J. Daniels F. El Ghandour A. et al.Identification of the CD4(+) T cell as a major pathogenic factor in ischemic acute renal failure.J Clin Invest. 2001; 108: 1283-1290Crossref PubMed Scopus (366) Google Scholar, 3.Burne-Taney M.J. Ascon D.B. Daniels F. et al.B cell deficiency confers protection from renal ischemia reperfusion injury.J Immunol. 2003; 171: 3210-3215Crossref PubMed Scopus (147) Google Scholar, 4.Day Y.J. Huang L. Ye H. et al.Renal ischemia-reperfusion injury and adenosine 2A receptor-mediated tissue protection: the role of CD4+ T cells and IFN-gamma.J Immunol. 2006; 176: 3108-3114Crossref PubMed Scopus (171) Google Scholar, 5.Day Y.J. Huang L. Ye H. et al.Renal ischemia-reperfusion injury and adenosine 2A receptor-mediated tissue protection: role of macrophages.Am J Physiol Renal Physiol. 2005; 288: F722-F731Crossref PubMed Scopus (210) Google Scholar, 6.Kelly K.J. Williams Jr, W.W. Colvin R.B. et al.Intercellular adhesion molecule-1-deficient mice are protected against ischemic renal injury.J Clin Invest. 1996; 97: 1056-1063Crossref PubMed Scopus (637) Google Scholar, 7.Li L. Huang L. Sung S.S. et al.NKT cell activation mediates neutrophil IFN-gamma production and renal ischemia-reperfusion injury.J Immunol. 2007; 178: 5899-5911Crossref PubMed Scopus (249) Google Scholar The innate immune response to IRI involves the activation and accumulation of neutrophils and macrophages in the post-ischemic kidney, and depletion of neutrophils or macrophages in mouse models is sufficient to preserve kidney function after IRI.5.Day Y.J. Huang L. Ye H. et al.Renal ischemia-reperfusion injury and adenosine 2A receptor-mediated tissue protection: role of macrophages.Am J Physiol Renal Physiol. 2005; 288: F722-F731Crossref PubMed Scopus (210) Google Scholar, 6.Kelly K.J. Williams Jr, W.W. Colvin R.B. et al.Intercellular adhesion molecule-1-deficient mice are protected against ischemic renal injury.J Clin Invest. 1996; 97: 1056-1063Crossref PubMed Scopus (637) Google Scholar, 7.Li L. Huang L. Sung S.S. et al.NKT cell activation mediates neutrophil IFN-gamma production and renal ischemia-reperfusion injury.J Immunol. 2007; 178: 5899-5911Crossref PubMed Scopus (249) Google Scholar, 8.Awad A.S. Rouse M. Huang L. et al.Compartmentalization of neutrophils in the kidney and lung following acute ischemic kidney injury.Kidney Int. 2009; 75: 689-698Abstract Full Text Full Text PDF PubMed Scopus (151) Google Scholar, 9.Li L. Huang L. Sung S.S. et al.The chemokine receptors CCR2 and CX3CR1 mediate monocyte/macrophage trafficking in kidney ischemia-reperfusion injury.Kidney Int. 2008Abstract Full Text Full Text PDF Scopus (238) Google Scholar, 10.Oh D.J. Dursun B. He Z. et al.Fractalkine receptor (CX3CR1) inhibition is protective against ischemic acute renal failure in mice.Am J Physiol Renal Physiol. 2008; 294: F264-F271Crossref PubMed Scopus (107) Google Scholar Similar to the heart, the kidney has the ability to be preconditioned by a nonlethal period of ischemia, rendering the kidney refractory to further ischemia-induced dysfunction (ischemic preconditioning, IPC11.Burne-Taney M.J. Liu M. Baldwin W.M. et al.Decreased capacity of immune cells to cause tissue injury mediates kidney ischemic preconditioning.J Immunol. 2006; 176: 7015-7020Crossref PubMed Scopus (41) Google Scholar, 12.Grenz A. Osswald H. Eckle T. et al.The reno-vascular A2B adenosine receptor protects the kidney from ischemia.PLoS Med. 2008; 5: e137Crossref PubMed Scopus (164) Google Scholar, 13.Lee H.T. Emala C.W. Protective effects of renal ischemic preconditioning and adenosine pretreatment: role of A(1) and A(3) receptors.Am J Physiol Renal Physiol. 2000; 278: F380-F387PubMed Google Scholar, 14.Park K.M. Chen A. Bonventre J.V. Prevention of kidney ischemia/reperfusion-induced functional injury and JNK, p38, and MAPK kinase activation by remote ischemic pretreatment.J Biol Chem. 2001; 276: 11870-11876Crossref PubMed Scopus (269) Google Scholar). Kidney IPC leads to increased renal pro-survival signals: HSP 27 expression14.Park K.M. Chen A. Bonventre J.V. Prevention of kidney ischemia/reperfusion-induced functional injury and JNK, p38, and MAPK kinase activation by remote ischemic pretreatment.J Biol Chem. 2001; 276: 11870-11876Crossref PubMed Scopus (269) Google Scholar and Akt phosphorylation,13.Lee H.T. Emala C.W. Protective effects of renal ischemic preconditioning and adenosine pretreatment: role of A(1) and A(3) receptors.Am J Physiol Renal Physiol. 2000; 278: F380-F387PubMed Google Scholar and decreased phosphorylation of cell-death-promoting p38 and Jun kinase.14.Park K.M. Chen A. Bonventre J.V. Prevention of kidney ischemia/reperfusion-induced functional injury and JNK, p38, and MAPK kinase activation by remote ischemic pretreatment.J Biol Chem. 2001; 276: 11870-11876Crossref PubMed Scopus (269) Google Scholar In addition, adenosine receptor activation or inhibition mimics or prevents the protective effect of IPC, respectively.12.Grenz A. Osswald H. Eckle T. et al.The reno-vascular A2B adenosine receptor protects the kidney from ischemia.PLoS Med. 2008; 5: e137Crossref PubMed Scopus (164) Google Scholar,13.Lee H.T. Emala C.W. Protective effects of renal ischemic preconditioning and adenosine pretreatment: role of A(1) and A(3) receptors.Am J Physiol Renal Physiol. 2000; 278: F380-F387PubMed Google Scholar Important studies recently showed that adoptive transfer of kidney lymphocytes from preconditioned mice to non-preconditioned recipients confers protection from kidney IRI.11.Burne-Taney M.J. Liu M. Baldwin W.M. et al.Decreased capacity of immune cells to cause tissue injury mediates kidney ischemic preconditioning.J Immunol. 2006; 176: 7015-7020Crossref PubMed Scopus (41) Google Scholar These findings suggest that accumulation of lymphocytes with protective properties in the post-ischemic kidney may mediate IPC. Regulatory T (Treg) cells are anti-inflammatory lymphocytes that have been recently identified in normal mouse kidneys.15.Ascon D.B. Ascon M. Satpute S. et al.Normal mouse kidneys contain activated and CD3+CD4-CD8- double-negative T lymphocytes with a distinct TCR repertoire.J Leukoc Biol. 2008Crossref Scopus (58) Google Scholar, 16.Gandolfo M.T. Jang H.R. Bagnasco S.M. et al.Foxp3(+) regulatory T cells participate in repair of ischemic acute kidney injury.Kidney Int. 2009; 76: 717-729Abstract Full Text Full Text PDF PubMed Scopus (201) Google Scholar, 17.Kinsey G.R. Sharma R. Huang L. et al.Regulatory T cells suppress innate immunity in kidney ischemia-reperfusion injury.J Am Soc Nephrol. 2009; 20: 1744-1753Crossref PubMed Scopus (269) Google Scholar Expression of the interleukin-2 (IL-2) receptor (CD25) and the transcription factor FoxP3 identify a highly suppressive subset of CD4+ Treg cells. These lymphocytes use multiple mechanisms to inhibit the function and proliferation of pro-inflammatory leukocytes, including production of IL-10 and/or transforming growth factor-β, cell-contact-dependent inhibition or generation of extracellular adenosine.18.Borsellino G. Kleinewietfeld M. Di Mitri D. et al.Expression of ectonucleotidase CD39 by Foxp3+ Treg cells: hydrolysis of extracellular ATP and immune suppression.Blood. 2007; 110: 1225-1232Crossref PubMed Scopus (849) Google Scholar, 19.Buckner J.H. Ziegler S.F. Regulating the immune system: the induction of regulatory T cells in the periphery.Arthritis Res Ther. 2004; 6: 215-222Crossref PubMed Scopus (65) Google Scholar, 20.Kobie J.J. Shah P.R. Yang L. et al.T regulatory and primed uncommitted CD4 T cells express CD73, which suppresses effector CD4 T cells by converting 5′-adenosine monophosphate to adenosine.J Immunol. 2006; 177: 6780-6786Crossref PubMed Scopus (305) Google Scholar, 21.Rubtsov Y.P. Rasmussen J.P. Chi E.Y. et al.Regulatory T cell-derived interleukin-10 limits inflammation at environmental interfaces.Immunity. 2008; 28: 546-558Abstract Full Text Full Text PDF PubMed Scopus (992) Google Scholar, 22.Watanabe K. Rao V.P. Poutahidis T. et al.CTLA-4 blockade abrogates protection by regulatory T cells in a mouse model of microbially-induced innate immune-driven colitis.Infect Immun. 2008; 76 (IAI.00542-00508): 5834-5842Crossref PubMed Scopus (28) Google Scholar Another important property of Treg cells is their propensity to home to areas of ongoing inflammation.23.Huehn J. Hamann A. Homing to suppress: address codes for Treg migration.Trends Immunol. 2005; 26: 632-636Abstract Full Text Full Text PDF PubMed Scopus (143) Google Scholar,24.Wei S. Kryczek I. Zou W. Regulatory T-cell compartmentalization and trafficking.Blood. 2006; 108: 426-431Crossref PubMed Scopus (236) Google Scholar We hypothesized that ischemia/reperfusion would cause Treg cell accumulation in the kidney as a consequence of the associated inflammation, which in turn would protect the kidney from subsequent ischemia/reperfusion-induced inflammation and kidney injury. C57Bl/6 mice underwent 24 min of bilateral renal ischemia (preconditioning) or sham surgery (non-preconditioned controls) on day 0 and then were allowed to recover for 7 days. On day 7, both groups of mice underwent 28 min bilateral renal ischemia. At 24 h after the initial surgery, preconditioned mice exhibited a slight, but significant, decrease in renal function compared to non-preconditioned control mice, as measured by plasma creatinine (PCr) levels (Figure 1a). By 72 h of reperfusion, no differences were observed in PCr levels between groups (Figure 1a). At 24 h after 28 min IRI, non-preconditioned mice (sham/IRI) had severely decreased renal function, whereas preconditioned mice (IRI/IRI) were completely protected (Figure 1a). The increase in outer medulla acute tubular necrosis (ATN) observed in non-preconditioned mice after 28 min IRI was significantly reduced by IPC (Figure 1b–e). At 24 h after the second surgery, accumulation of neutrophils, macrophages, CD4+ T cells and B cells was assessed by flow cytometry. Neutrophil (CD45+7-AAD-CD11b+GR-1high) and macrophage (CD45+7-AAD-F4/80intLy6C+) numbers were markedly increased in the kidney after 28 min IRI in non-preconditioned mice (sham/IRI, Figure 2a and b). The increase in innate inflammatory leukocytes was significantly attenuated by IPC (IRI/IRI, Figure 2a and b). In contrast, the number of B cells (CD45+7-AAD-B220+CD19+) in kidneys was significantly increased in the preconditioned mice vs non-preconditioned mice, after 28 min IRI (B cells per gram kidney: 66,000±13,000 vs 150,000±38,000, n=7, P 0.05). Immunohistochemical analysis of frozen kidney sections using an antibody that recognizes neutrophils and recently emigrated monocytes (7/4; Henderson et al.25.Henderson R.B. Hobbs J.A.R. Mathies M. et al.Rapid recruitment of inflammatory monocytes is independent of neutrophil migration.Blood. 2003; 102: 328-335Crossref PubMed Scopus (229) Google Scholar and Taylor et al.26.Taylor P.R. Brown G.D. Geldhof A.B. et al.Pattern recognition receptors and differentiation antigens define murine myeloid cell heterogeneity ex vivo.Eur J Immunol. 2003; 33: 2090-2097Crossref PubMed Scopus (106) Google Scholar) confirmed the protective effect of IPC on innate leukocyte accumulation after IRI (Figure 2c–e). On the basis of the previously demonstrated ability of Treg cells to traffic to areas of inflammation,23.Huehn J. Hamann A. Homing to suppress: address codes for Treg migration.Trends Immunol. 2005; 26: 632-636Abstract Full Text Full Text PDF PubMed Scopus (143) Google Scholar,24.Wei S. Kryczek I. Zou W. Regulatory T-cell compartmentalization and trafficking.Blood. 2006; 108: 426-431Crossref PubMed Scopus (236) Google Scholar we hypothesized that kidney IRI would cause accumulation of Treg cells in the kidney. To test this, we measured the number of Treg cells in kidneys from mice at various time points after either sham surgery or 24 min bilateral renal ischemia by flow cytometry. Compared to sham-operated mice, we observed an approximately threefold increase in the number of CD4+CD25+FoxP3+ Treg cells in the kidney 7 days after IRI (Figure 3). The accumulation of Treg cells appeared to be kidney specific, because no difference in the number of these lymphocytes was observed in the spleen. The observed increase in kidney Treg cell number was delayed and transient as no increase was noted at 3 or 14 days after IRI (Figure 3). This is consistent with the finding that preconditioning was incomplete at day 3. PCr was 0.16±0.05 vs 0.33±0.03 mg/dl for sham/sham vs IRI/IRI, respectively (P<0.05), when preconditioned mice underwent 28 min IRI at day 3, and 0.17±0.03 vs 0.26±0.02 mg/dl for sham/sham vs IRI/IRI, respectively (P=not significant), when preconditioned mice underwent 28 min IRI at day 7. To investigate the location of the accumulating Treg cells in the kidney, we performed immunohistochemical analysis with antibodies to CD4 and FoxP3. This revealed that CD4+FoxP3+ Treg cells were observed at similar frequencies inside kidney vascular structures in both sham-operated and post-ischemic kidneys (data not shown), but Treg cells were observed in the outer medulla interstitium only in post-ischemic kidneys (Figure 3b–d). To determine whether preconditioning also induces phenotypic changes in Treg cells, we performed intracellular cytokine staining on kidney CD4+CD25+ Treg cells for IL-10. Compared to Treg cells from non-preconditioned mouse kidneys, a greater percentage of Treg cells in kidneys of preconditioned mice expressed IL-10 (Figure 4). This increase in percentage translates into a more than eightfold increase in the number of IL-10+ Treg cells per kidney in preconditioned mice.Figure 4Kidney ischemia/reperfusion injury causes increased IL-10 production by kidney Treg cells. At 7 days after 24 min IRI (preconditioned) or sham (non-preconditioned) surgery, mouse kidneys were harvested, digested, and stained for Treg cell-surface markers CD4 and CD25, and stained for intracellular IL-10 as described in the Materials and Methods section. The percentage (a) and absolute number (b) of IL-10+ Treg cells per kidney in preconditioned and non-preconditioned mice are represented as the mean+s.e.m.; *P 0.05). In contrast, 24 h after 28 min ischemia (day 8) the non-preconditioned IgG-treated mice (sham/IRI-IgG) exhibited a severe decline in renal function, whereas preconditioned IgG-treated mice (IRI/IRI-IgG) retained normal renal function, as measured by PCr levels (Figure 7a). Partial Treg cell depletion, in preconditioned mice (IRI/IRI-PC61), significantly inhibited the protective effect of IPC on renal function after IRI (Figure 7a). Histological analysis of outer medulla ATN was consistent with functional observations, revealing a partial block of the protective effect of IPC on ATN by decreasing Treg cell numbers in preconditioned mice (Figure 7b and c). Outer medulla ATN scores in preconditioned mice treated with IgG vs PC61 were 1.0±0.2 and 2.6±0.3, respectively (P<0.05). To test the ability of increasing Treg numbers in mice to protect the kidney from IRI, we performed adoptive transfer of 1 × 105 or 1 × 106 Treg cells (CD4+CD25+) or 1 × 106 non-Treg lymphocytes (CD4+CD25-) isolated from WT C57Bl/6 mice to naive WT C57Bl/6 recipients 18 h before 28 min bilateral renal ischemia. The freshly isolated Treg cells highly expressed FoxP3, as previously described (Kinsey et al.,17.Kinsey G.R. Sharma R. Huang L. et al.Regulatory T cells suppress innate immunity in kidney ischemia-reperfusion injury.J Am Soc Nephrol. 2009; 20: 1744-1753Crossref PubMed Scopus (269) Google Scholar data not shown). The mice that received 1 × 106 CD4+CD25- non-Treg lymphocytes before IRI exhibited a loss of kidney function (Figure 8a) and marked accumulation of neutrophils and macrophages (Figure 9) compared to sham-operated controls. Adoptive transfer of 1 × 105 Treg cells partially inhibited neutrophil accumulation and preserved renal function, and 1 × 106 Treg cells completely blocked the loss of function and neutrophil and macrophage accumulation induced by IRI (Figures 8 and 9). Adoptive transfer of Treg cells had a dose-dependent protective effect on ATN (Figure 8b–e). Outer medulla 7/4 staining confirmed the flow cytometry results showing dose-dependent protection from IRI-induced inflammation in the mice receiving Treg cells (Figure 9c–e).Figure 9Adoptive transfer of Treg cells prevents ischemia/reperfusion-induced inflammation. At 18 h before 28 min bilateral renal ischemia, naive C57Bl/6 mice were administered either 1 × 106 CD4+CD25- non-Treg lymphocytes (CD25-), 1 × 105, or 1 × 106 CD4+CD25+ Treg cells by tail vein injection. At 24 h after sham surgery or IRI, kidney neutrophil (a) and macrophage (b) accumulation was measured by flow cytometry. Frozen kidney sections were stained with an antibody that recognizes neutrophils and recently emigrated monocytes (7/4) to assess renal accumulation in the different treatment groups (c–e). Data are presented as the mean+s.e.m., means with different labels are significantly different from each other, P 20 min) followed by a recovery period of 6–8 days.11.Burne-Taney M.J. Liu M. Baldwin W.M. et al.Decreased capacity of immune cells to cause tissue injury mediates kidney ischemic preconditioning.J Immunol. 2006; 176: 7015-7020Crossref PubMed Scopus (41) Google Scholar,14.Park K.M. Chen A. Bonventre J.V. Prevention of kidney ischemia/reperfusion-induced functional injury and JNK, p38, and MAPK kinase activation by remote ischemic pretreatment.J Biol Chem. 2001; 276: 11870-11876Crossref PubMed Scopus (269) Google Scholar After this procedure, mice are completely protected from subsequent ischemic injury for more than 1 week and partially protected for up to 12 weeks.14.Park K.M. Chen A. Bonventre J.V. Prevention of kidney ischemia/reperfusion-induced functional injury and JNK, p38, and MAPK kinase activation by remote ischemic pretreatment.J Biol Chem. 2001; 276: 11870-11876Crossref PubMed Scopus (269) Google Scholar We used a model of delayed IPC that resulted in complete functional protection of the kidney from severe ischemic injury 7 days after the initial preconditioning surgery. This model of IPC markedly decreased the infiltration of neutrophils and macrophages in the post-ischemic kidney, which are both known to cause renal injury.5.Day Y.J. Huang L. Ye H. et al.Renal ischemia-reperfusion injury and adenosine 2A receptor-mediated tissue protection: role of macrophages.Am J Physiol Renal Physiol. 2005; 288: F722-F731Crossref PubMed Scopus (210) Google Scholar, 6.Kelly K.J. Williams Jr, W.W. Colvin R.B. et al.Intercellular adhesion molecule-1-deficient mice are protected against ischemic renal injury.J Clin Invest. 1996; 97: 1056-1063Crossref PubMed Scopus (637) Google Scholar, 7.Li L. Huang L. Sung S.S. et al.NKT cell activation mediates neutrophil IFN-gamma production and renal ischemia-reperfusion injury.J Immunol. 2007; 178: 5899-5911Crossref PubMed Scopus (249) Google Scholar, 8.Awad A.S. Rouse M. Huang L. et al.Compartmentalization of neutrophils in the kidney and lung following acute ischemic kidney injury.Kidney Int. 2009; 75: 689-698Abstract Full Text Full Text PDF PubMed Scopus (151) Google Scholar, 9.Li L. Huang L. Sung S.S. et al.The chemokine receptors CCR2 and CX3CR1 mediate monocyte/macrophage trafficking in kidney ischemia-reperfusion injury.Kidney Int. 2008Abstract Full Text Full Text PDF Scopus (238) Google Scholar, 10.Oh D.J. Dursun B. He Z. et al.Fractalkine receptor (CX3CR1) inhibition is protective against ischemic acute renal failure in mice.Am J Physiol Renal Physiol. 2008; 294: F264-F271Crossref PubMed Scopus (107) Google Scholar A report from Ascon et al.30.Ascon D.B. Lopez-Briones S. Liu M. et al.Phenotypic and functional characterization of kidney-infiltrating lymphocytes in renal ischemia reperfusion injury.J Immunol. 2006; 177: 3380-3387Crossref PubMed Scopus (119) Google Scholar showed that adoptive transfer of lymphocytes from kidneys of preconditioned mice conferred protection against renal IRI in naive T-cell-deficient mice, suggesting that renal IRI causes kidney accumulation of lymphocytes with a protective (potentially anti-inflammatory) phenotype. Characterization of the specific lymphocyte (T or B cell) subset(s) responsible for the protection was not reported. We hypothesized that the highly immunosuppressive CD4+CD25+ Treg cells (expressing FoxP3+ and/or IL-10) could be important mediators of kidney IPC for several reasons. First, we have recently shown that CD4+CD25+FoxP3+ Treg cells are an intrinsic protective mechanism against kidney IRI in naive mice, which directly and potent
Referência(s)