Chronic allograft nephropathy in athymic nude rats after adoptive transfer of primed T lymphocytes

The impact of presensitized T lymphocytes on the development of chronic allograft nephropathy (CAN) was investigated in nude athymic LEW.RNU recipients of F344 renal allografts. The recipients (n = 8) were reconstituted with 5 x 10(7) T lymphocytes primed against donor skin grafts to induce graft rejection. LEW.RNU (n = 8) and euthymic LEW recipients (n = 6) which underwent no further intervention after transplantation served as control groups. Adoptive transfer of primed T cells induced CAN in LEW.RNU rats. Their kidney function decreased progressively. After 90 days a moderate glomerulopathy, tubular atrophy and interstitial fibrosis were observed, vascular changes were only mild or absent. Cellular infiltrates were predominated by CD4+ T cells and ED1+ macrophages. Deposition of tenascin and laminin was enhanced. Grafts of euthymic recipients displayed only mild signs of CAN according to the Banff criteria. These data implicate an important role for the cellular immune response in the development of CAN.     

Effects of everolimus on cellular and humoral immune processes leading to chronic allograft nephropathy in a rat model with sensitized recipients

BACKGROUND: Chronic allograft nephropathy (CAN) remains the most common cause of late graft loss especially in sensitized patients. The aim of this study is to evaluate the therapeutic effect of everolimus on cellular and humoral mechanisms of chronic allograft damage in a rat model with sensitized recipients. METHODS: F344 kidneys were transplanted to LEW.RNU rats. The athymic recipients were reconstituted with 3.5 x 10(7) or 5 x 10(7) presensitized CD4+T-lymphocytes. In the treatment group, everolimus was introduced five weeks posttransplantation. Rats were monitored for peripheral blood lymphocytes, renal function, histological changes in the graft, and the development of donor-specific alloantibodies. RESULTS: Rats developed cell dose-dependent renal failure. Increased urinary albumin excretion and glomerulopathy were frequently accompanied by the development of donor-specific major histocompatibility complex (MHC) alloantibodies. In the everolimus group, five of six animals survived for 20 weeks with stable serum creatinine and displayed neither acute cellular rejection nor CAN. Prolonged survival was accompanied with significantly reduced tubulointerstitial cell infiltrate in the graft. Increased urinary albumin excretion was present in all, acute tubular necrosis in five of six, and glomerular sclerosis in two grafts. MHC alloantibodies were found in four of six animals. CONCLUSION: The used rat model offers the opportunity to study the influence of everolimus on the interaction of humoral and cellular mechanisms involved in chronic renal damage. Everolimus leads to a prolongation of allograft survival, reduced cell infiltrate in the graft, and prevents tubular atrophy and interstitial fibrosis. The development of alloantibodies and albuminuria was not prevented. These data suggest that although cellular rejection is clearly suppressed, humoral mechanisms of CAN cannot be completely controlled by everolimus treatment in the sensitized rat model.     

A critical role for human CD4+ T-cells in rejection of porcine islet cell xenografts

T-cell-mediated rejection is likely to present a significant barrier to porcine islet xenotransplantation. Little is known, however, about human anti-porcine islet rejection because no suitable model exists to study this process. To address this problem, we have developed an immunodeficient mouse model to study rejection of fetal porcine islet cell clusters (ICCs) by human lymphocytes. Transplantation of porcine ICCs into hyperglycemic recombinase activating gene-deficient (R-) mice restores normal blood glucose levels within 5 weeks. Adoptive transfer of in vitro-stimulated human peripheral blood mononuclear cells into R- mice before islet cell transplantation leads to acute cellular rejection of porcine ICCs. The first human cells observed to infiltrate rejecting grafts are CD4+ T-cells. Although CD8+ T-cells are observed within the grafts at later time points, CD4+ T-cells predominate until the graft is destroyed. Adoptive transfer of purified human CD4+ T-cells before ICC transplantation is sufficient to cause acute cellular rejection. These data demonstrate that human CD4+ T-cells play a critical role in porcine ICC xenograft rejection.     

Allograft rejection in CD4+ T cell-reconstituted athymic nude rats--the nonessential role of host-derived CD8+ cells.

PVG-rnu/rnu nude rats reject fully allogenic renal (DA) and skin (BN, AO) allografts after the adoptive transfer of naive CD4+ T cells alone, but rejection is accompanied by the accumulation of many nude-derived CD8+ leukocytes within the graft. In addition, mononuclear cells infiltrating the rejecting renal grafts in these animals display cytotoxic activity in vitro against specific and third-party alloantigens. In this investigation we have treated CD4+ T cell-restored nude rats bearing renal or skin allografts with the mAb MRC OX8 to deplete the host of CD8+ cells. In vivo treatment with OX8 completely eliminated CD8+ cells from rejecting grafts of both kidney and skin, but it did not prevent graft rejection, nor did OX8 treatment abolish the cytotoxic effector cells found in nude rat spleen or in graft-infiltrating cells (GIC) of rejecting renal allografts. The nature of the cytotoxic activity was examined with anti-CD3 mAb 1F4, which was shown to block conventional CD8+ Tc killing in vitro but did not inhibit allogeneic target cell lysis by spleen cells from nude rats. The cytotoxic activity found in GIC of rejecting allografts was not inhibited by anti-CD3 mAb, suggesting that these cytotoxic effector cells were CD3-CD8- and were of extrathymic origin. We conclude that non-thymus-derived CD8+ GIC are not essential for allograft rejection in CD4+ T cell-restored nude rats.     

Renal allograft rejection in CD4+ T cell-reconstituted athymic nude rats. The origin of CD4+ and CD8+ graft-infiltrating cells

PVG-rnu/rnu nude rats reject a fully allogeneic DA renal allograft after the adoptive transfer of naive CD4+ T cells alone, but rejection is accompanied by the accumulation of many CD8+ leukocytes within the graft. In order to clearly establish the provenance of these CD8+ cells infiltrating rejecting kidney allografts, nude recipients (PVG-RT7a) were injected with CD4+ T cells from the PVG-RT7b congenic strain bearing an allotypic variant of the leukocyte-common antigen. Dual fluorescence and immunohistochemistry demonstrated that approximately 75% of the total infiltrate was host-derived; the donor-derived RT7b population was almost entirely (92-99%) CD4+, CD5+, CD3+, and alpha beta TCR+. At least 97% of the CD8+ cells were of nude origin. There was no evidence of donor-derived CD8+ cells or of a CD4+8+ double-staining population. Unexpectedly, nearly half of the alpha beta TCR+ cells from the grafts were of nude origin.     

Induction of chronic renal allograft injury by injection of a monoclonal antibody against a donor MHC Ib molecule in a nude rat model

BACKGROUND: Chronic allograft injury induced by immunological as well as non-immunological mechanisms is still a major cause of long-term graft loss after renal transplantation. Major histocompatibility complex (MHC) incompatibilities as well as donor-specific alloantibodies are known risk factors, but the interaction of cellular and humoral mechanisms leading to allograft damage remains to be defined. The aim of this study was to analyze the impact of donor-specific post-transplant antibodies against a non-classical MHC Ib antigen apart from T-cell-dependent immune response. Therefore, we utilized a transplant rat model injecting a moAb directed against a donor MHC Ib molecule into athymic nude recipients lacking an immunocompetent T-cell system. METHODS: F344 kidneys were transplanted into LEW.RNU rats. Donor and recipient differ in the RT1.C locus (MHC Ib) but are phenotypically identical for the RT1.A (MHC I) and RT1.B/D (MHC II) loci. A moAb directed against the donors RT1.C(lv1) was injected into recipients with stable graft function. A control group remained untreated after transplantation. The rats were monitored for renal function and grafts were analyzed for morphological changes, infiltrating cells and C4d deposition. RESULTS: Antibody-infused rats developed renal impairment with massive urine albumin excretion. Histological changes consistent with antibody-mediated injury were interstitial fibrosis, tubular atrophy and severe glomerulopathy accompanied by an infiltrate of numerous macrophages. At time of death, grafts were negative for C4d at the peritubular capillaries and arterial endothelium. CONCLUSION: Antibodies directed against a MHC Ib antigen are able to induce allograft injury in T-cell-deficient rats. This model underlines the role of non-classical MHC disparities for long-term allograft survival and demonstrates the long-term results of antibody-induced allograft damage.     

Multiple pathways in the rejection of skin grafts.

We have analyzed the ability of CD4+ and CD8+ T cells to cause rejection of skin grafts in an Ir gene high responder strain. (DA.RT1u x DA.RT1c)F1 B rats (thymectomized, lethally irradiated, reconstituted with fetal liver cells) were grafted with ear skin of the recombinant strain, DA.RT1rl. The only allogeneic difference was a single class I MHC antigen. The B rats, which do not reject these grafts due to the absence of T cells, were reconstituted at various time intervals after skin grafting with either unsorted lymph node cells (LNCs), CD4+, CD8+ or CD4+ and CD8+ T cells. Unsorted LNCs given any time after graft placement always caused rejection (MST = 15d). CD4+ cells alone never caused rejection (MST greater than 60d, n = 8). CD8+ cells alone caused rejection if given within 3 weeks of graft placement. Thereafter, CD8+ cells alone lost their ability to cause rejection (MST greater than 60d, n = 6). B rats with grafts in place more than 3 weeks, when CD8+ cells alone were ineffective, rejected their skin grafts when given both CD8+ and CD4+ cells. These data suggest that there may be two T cell pathways in skin graft rejection. The first requires only CD8+ cells and causes rejection of a recently placed graft. The second pathway requires both CD4+ and CD8+ cells to reject long-standing grafts in which donor antigen-presenting cells have been putatively depleted and, therefore, may be dependent on host antigen-presenting cells.     

Wegener's granulomatosis: inflammatory cells and markers of repair and fibrosis in renal biopsies--a clinicopathological study.

OBJECTIVE: This study aimed to quantitate inflammatory cells in renal biopsies from patients with Wegener's granulomatosis (WG) and to identify cells participating in early fibrogenesis. The goal was to determine whether these cells correlated with the severity of renal disease and whether their presence had a bearing on renal prognosis. MATERIAL AND METHODS: Sixty-one patients with WG who had a renal biopsy taken at the time of diagnosis were included in the study. Immunostaining with monoclonal antibodies towards macrophages (CD68), T- and B-lymphocytes, alpha-smooth muscle actin (alpha-SMA) and vimentin was done. RESULTS: The dominating intraglomerular leucocytes were macrophages (29.9 +/- 15 cells/glomerular cross-section) and to a lesser extent T-cells (2.57 +/- 1.8 cells/glomerular cross-section). No B-lymphocytes were detected in the glomeruli. More than two-thirds of the T-cells were CD8+ (cytotoxic) cells. Macrophages and T-lymphocytes were distributed equally in the renal interstitium and were numerous around crescentic glomeruli. Glomerular and interstitial macrophages and interstitial T-cells correlated significantly with serum (S-) creatinine at the time of biopsy but not after 1 year. S-creatinine at the time of biopsy and after 1 year differed significantly among the three levels of interstitial alpha-SMA staining. S-creatinine at biopsy was highest when tubular vimentin staining was strongest, and tubular vimentin staining was strongest in patients with acute tubular damage. CONCLUSIONS: Evidence was found for a cellular type IV immune response in WG, with CD8+ T-lymphocytes and macrophages dominating the cellular infiltrate. The detection of interstitial alpha-SMA, probably staining myofibroblasts implicated in renal fibrogenesis, indicated a low glomerular filtration rate 1 year after renal biopsy.     

Combination of donor-specific blood transfusion with anti-CD28 antibody synergizes to prolong graft survival in rat liver transplantation

Donor-specific blood transfusion (DST) has been shown to effectively induce tolerance to certain allografts. In addition, it is well known that blockade of costimulatory signals reduces the ability of T cells to respond to alloantigens, prolonging allograft survival in some transplant models. We assessed the effects of single or multiple DSTs in the absence or presence of anti-CD28 monoclonal antibodies (mAbs) on graft function and host survival in rat liver transplantation (LTx). Fully MHC-mismatched adult male Dark Agouti (DA) and Lewis (LEW) rats were used as donors and recipients, respectively. Heparinized DA blood was administered to na?ve LEW rats 7 days before LTx [DST(-7d)], 14 and 7 days before LTx [DST(1 x 2)], twice a week for 2 weeks prior to LTx [DST(2 x 2)] and once a week for 4 weeks prior to LTx [DST(1 x 4)]. For some experiments, two different monoclonal antibodies (mAb) to rat CD28 (JJ316 and JJ319) were administered in combination with some DST treatments. We found that DST administration induced a time- and dose-dependent increase in host survival. Treatment of LEW rats with JJ316 or JJ319 mAb alone failed to prolong graft survival over untreated rats; however, the combination of DST(1 x 2) with JJ316 or JJ319 mAb induced indefinite survival at 100 days following surgery. We found that this protective effect was associated with increased numbers of splenic CD4+ CD45RC- but not CD4+ CD25+ foxp3+ T-cells in long-term survivors. Our data suggest that the combination of suboptimal DST with CD28 mAb induces donor-specific tolerance that correlates with enhanced numbers of regulatory T-cells.     

T cell subsets mediating rejection of established fetal pancreas grafts and failure to observe graft adaptation

The present study has attempted to elucidate the cellular mechanisms by which long-term established fetal pancreas allografts are rejected. We used an experimental model in which H-2b nude mice were made hyperglycemic by streptozotocin treatment and then engrafted with allogeneic fetal pancreas grafts. These grafts were functional in that engrafted animals returned to near normoglycemia while all animals left unengrafted subsequently died. The fetal pancreas grafts were allowed to reside in the immunoincompetent nude host for 6-9 months prior to T cell reconstitution, at which time animals were reconstituted with either negatively selected CD4+ or CD8+ H-2b T cell subpopulations. We found that a 6-9 month residence in an immunoincompetent host did not lead to a change in the immunogenicity of fetal pancreatic grafts in that both CD4+ and CD8+ T cell subsets were capable of rejecting these long-term established fetal pancreas grafts. The finding that isolated CD8+ spleen T cell subpopulations, which are only activated by antigen-presenting cells of donor origin bearing MHC class I alloantigen, were capable of effecting graft rejection suggested that APC of donor origin persisted in these long-term fetal pancreas allografts.     

Differential effects of interleukin 2 receptor-targeted therapy on heart and kidney allografts in rats. Depression of effectiveness of ART-18 monoclonal antibody treatment by uremia

ART-18, a mouse antirat IL-2R mAb inhibits IL-2 binding and IL-2-dependent T cell growth. Although both (LEW x BN)F1 kidney and heart allografts survive ca. 3 weeks in ART-18-treated LEW rats (acute rejection occurs within 10 days, P less than 0.001), the host responses against the two organs vary. In the heart model, the splenic CD4:CD8 ratio as determined by FMF was similar both in untreated and treated animals, but decreased significantly in kidney recipients conditioned with ART-18. In both mAb-modulated animal groups, splenocytes inhibited test MLR and prolonged test cardiac allograft survival in a donor-specific fashion upon adoptive transfer, suggesting that ART-18 mediates "sparing" of Ts. However, both CD4+ and CD8+ cells from kidney-grafted hosts conferred suppression in vivo; only the CD8+ subset was effective in the heart model. Immunohistologically, IL-2R+ cells were absent in the heart grafts of treated hosts; a significant proportion of the kidney cell infiltrate remained IL-2R+ despite continuous mAb administration. Although ART-18 therapy prolonged renal graft survival significantly, function was poor and the rats remained uremic. However, when one of the native kidneys was retained and the rat continued to enjoy normal renal function, IL-2R+ cells were abolished from the graft infiltrate, as shown by FMF and immunohistology. Thus, ART-18 treatment influences host responses differentially against kidney and heart allografts (modulation and depletion of IL-2R+ cells, respectively) despite increasing their survival comparably. The uremic state in the kidney model prevents elimination of infiltrating IL-2R+ mononuclear cells by a mAb directed specifically against them.     

CD4 T-Cell Regulation of Cytotoxic T Cells During the Induction Phase of Liver-Induced Spontaneous Tolerance in Rats

Purpose To check for in vivo CD4 T-cell-mediated inhibition of the immune response in rats with spontaneously accepted liver transplants.Methods Using the Lewis to Wistar Furth rat strain combination, we performed transient in vivo depletion of CD4 T-cells by anti-CD4 monoclonal antibodies (mAb) after liver transplantation. We used the CTL assay to detect primed T cells. We also retransplanted a grafted donor liver, parked for 3 days, into a secondary naive recipient rat.Results When Lewis rat livers were transplanted into the recipient Wistar Furth rats, the grafts suffered an early immune attack, followed by spontaneous acceptance without immunosuppression. However, giving anti-CD4 mAb to the recipients at the time of grafting prolonged the acute rejection reaction. Furthermore, giving anti-CD4 therapy on postoperative days (PODs) 21 and 35, but not on PODs 56 and 100, induced transient liver damage in recipients overcoming acute rejection. No primed T cells were detected by the CTL assay in the recipient rats within 2 months after transplantation. Meanwhile, the retransplanted liver had no ability to elicit an immune attack.Conclusions CD4 T cells seemed to downregulate the effector function of T cells, but not T-cell proliferation in this model.     

Anti-CD4 induced rat heart tolerance: no presence of primed T cells and regulatory mechanisms for cytotoxic T cells

Treatment with anti-CD4 monoclonal antibody (mAb) (OX38) induces heart, but not skin graft tolerance in WF (RT1u) to Lewis (RT1l) rat strain combinations. We examined differences in cellular responses between heart-bearing and skin-rejected hosts that were both treated with anti-CD4 mAb. In the tolerant LEW rats bearing WF heart transplants, the secondary WF heart but not skin grafts were accepted. On the other hand, in anti-CD4 treated WF skin-rejected hosts, both secondary WF heart and skin grafts were rapidly rejected. Spleen cells from anti-CD4 treated WF skin-rejected LEW rats but not from WF heart-bearing LEW rats received the same treatment generated CTL after in vitro stimulation with paraformaldehyde (PFA) treated donor WF stimulator spleen cells. Adoptive transfer of spleen cells from WF skin-rejected LEW rats with or without anti-CD4 therapy into the tolerant LEW rats at the secondary WF heart transplantation blocked the secondary heart graft acceptance. However, transfer of spleen cells from WF heart-rejected rats without immunosuppression failed to block acceptance of the secondary heart graft. Our results indicated the lack of primed T cells and presence of regulatory mechanisms for tissue specific T cells in anti-CD4 treated heart bearing hosts.     

Primed allospecific T cells prevent the effects of costimulatory blockade on prolonged cardiac allograft survival in mice.

Costimulatory blockade can induce long‐term allograft survival in naïve animals, but may not be as effective in animals with previously primed immune repertoires. We attempted to induce long‐term graft survival in B10.D2 recipients of B10.A cardiac allografts using donor‐specific transfusion (DST) plus anti‐CD40 ligand antibody (αCD40L). Recipients were either naïve mice, or mice previously primed to B10.A or third party alloantigens through engraftment and rejection of skin transplants. Untreated naïve mice rejected cardiac transplants by day 15 and contained a high frequency of primed, donor‐reactive T cells. Donor‐specific transfusion/αCD40L treatment of naïve animals induced long‐term graft survival associated with low frequencies of donor‐reactive T cells. Previous priming of donor‐specific T cells through rejection of B10.A, but not third party, skin grafts prevented the effects of DST/αCD40L on prolonging survival of B10.A hearts. Moreover, adoptive transfer of CD3+, CD4+ or CD8+ T cells from B10.A skin‐graft‐primed animals prevented the effects of DST/αCD40L. The data demonstrate that animals with immune repertoires containing previously primed, donor‐reactive T cells are resistant to the effects of costimulatory blockade. The findings have important implications for ongoing, costimulatory blockade‐based trials in humans, whose T‐cell repertoires are known to contain memory alloreactive T cells.     

Pyelonephritis: the role of cell-mediated immunity defined in a congenitally athymic rat

Thymus-derived lymphocytes (T-cells) have been shown to be present in the inflammatory infiltrate in renal infection but their role in host defense mechanisms has not been defined. Indirect evidence suggested that T-cells contributed to host protection but selective depletion of T-cells did not influence the course of pyelonephritis. In the present report, the characteristics of the athymic New Zealand nude rat (rnunz), which lacks T-lymphocytes, are detailed. This mutant was then used to assess the effect of an absence of T-cells on the bacteriological and histopathological features of pyelonephritis. No significant differences in the bacteriological course of the disease were found. Apart from fewer lymphocytes in the kidney lesions of nude rats and a slight, lag in the resolution of these lesions, no differences were observed in the histopathological course either. These observations, which have analyzed the quantitative relationship between cell-mediated immunity (CMI) and host resistance to renal infection, have shown that a gross reduction in CMI does not affect host resistance once bacteria have gained access to the kidney.     

Inhibition of chronic rejection and development of tolerogenic T cells after ICOS-ICOSL and CD40-CD40L co-stimulation blockade

BACKGROUND.: Blockade of the CD40-CD40L pathway results in long-term allograft survival but does not prevent chronic rejection. ICOS-ICOSL are members of the CD28-B7 family that play an important role in T-cell activation. METHODS.: The authors analyzed the effect of single or combined treatment with an anti-ICOS monoclonal antibody and CD40 immunoglobulin (Ig) on acute and chronic rejection of heart allografts in rats. RESULTS.: Treatment with anti-ICOS resulted in a modest but significant prolongation of allograft survival. Treatment with CD40Ig resulted in long-term graft survival but the cardiac grafts developed chronic rejection lesions. Combined CD40Ig+anti-ICOS treatment led to indefinite graft survival in all recipients and a significant decrease of chronic rejection lesions compared with CD40Ig alone. Importantly, four of the seven CD40Ig+anti-ICOS-treated recipients showed a complete absence of chronic rejection lesions, whereas all of the CD40Ig-treated recipients showed chronic rejection. The CD40Ig+anti-ICOS group also showed significant decreased graft infiltration, decreased antidonor cytotoxic T-lymphocyte activity, and decreased alloantibodies compared with the CD40Ig-treated group. Adoptive transfer of splenocytes indefinitely prolonged allograft survival, whereas those depleted of T cells did not, suggesting the development of T-regulatory mechanisms. CONCLUSIONS.: These data indicate that the chronic rejection mechanisms that are CD40-CD40L independent are ICOS-ICOSL dependent. These results were obtained with conservation of cognate immune responses and development of tolerogenic T cells.     

Inhibition of chronic rejection and development of tolerogenic T cells after ICOS-ICOSL and CD40-CD40L co-stimulation blockade

BACKGROUND: Blockade of the CD40-CD40L pathway results in long-term allograft survival but does not prevent chronic rejection. ICOS-ICOSL are members of the CD28-B7 family that play an important role in T-cell activation. METHODS: The authors analyzed the effect of single or combined treatment with an anti-ICOS monoclonal antibody and the fusion molecule CD40 immunoglobulin (Ig) on acute and chronic rejection of heart allografts in rats. RESULTS: Treatment with anti-ICOS resulted in a modest but significant prolongation of allograft survival. Treatment with CD40Ig resulted in long-term graft survival but the cardiac grafts developed chronic rejection lesions. Combined CD40Ig+anti-ICOS treatment led to indefinite graft survival in all recipients and a significant decrease of chronic rejection lesions compared with CD40Ig alone. Importantly, four of the seven CD40Ig+anti-ICOS-treated recipients showed a complete absence of chronic rejection lesions, whereas all of the CD40Ig-treated recipients showed chronic rejection. The CD40Ig+anti-ICOS group also showed significant decreased graft infiltration, decreased antidonor cytotoxic T-lymphocyte activity, and decreased alloantibodies compared with the CD40Ig-treated group. Adoptive transfer of splenocytes indefinitely prolonged allograft survival, whereas those depleted of T cells did not, suggesting the development of T-regulatory mechanisms. CONCLUSIONS. These data indicate that the chronic rejection mechanisms that are CD40-CD40L independent are ICOS-ICOSL dependent. These results were obtained with conservation of cognate immune responses and development of tolerogenic T cells.     

Morphometric analysis of cellular infiltration assessed by monoclonal antibody labeling in sequential human renal allograft biopsies

The mononuclear cell infiltrate in a total of 279 human renal allograft biopsies was determined by a panel of monoclonal antibodies using an indirect immunoperoxidase technique. Two hundred and seventy-two biopsies were obtained from 83 patients randomly allocated to receive short-term cyclosporine (CsA) or conventional azathioprine and low-dose prednisolone (AP). Biopsies were obtained routinely at days 0 (control biopsies), 7, 21, 90, and 365, as well as at other times when clinically indicated. A further 7 patients on AP therapy were biopsied several years after transplantation (median: 6 years 1 month). Morphometric analysis of cryostat tissue sections using a point-counting technique has shown that the infiltration in rejecting grafts is significantly greater than in grafts with stable function. However, significant infiltration also occurs within the first week after transplantation in grafts with stable function. While this infiltrate diminishes with time, it remains significant even in grafts biopsied several years after transplantation. The infiltration with CsA treatment is significantly less than with AP therapy. The magnitude of the infiltrate therefore varies with time, graft status, and immunosuppression. In contrast the phenotypic composition of the infiltrate remains relatively constant in all biopsies after transplantation with T lymphocytes (CD3+), accounting for approximately 35% of infiltrating cells and CD8+ cells more common than CD4+. Monocytes and macrophages account for most of the remainder of the infiltrate.     

大鼠供肾转染反义ERK2基因减缓肾移植后慢性移植肾肾病的作用及机制

目的 研究腺病毒介导的反义ERK2(A-dant-ERl(2)基因转染供肾对减缓肾移植后发生慢性移植肾肾病(CAN)的作用及机制.方法 建立大鼠间肾移植模型.按供肾移植前处理方式的不同分为对照组、空载病毒组和基因转染组,每组6只.对照组供肾灌注无菌HTK液0.5 ml,空载病毒组供肾灌注含5x109>pfu LaeZ基因腺病毒(Ad-LacZ)的HTK液0.5 ml,基因转染组供肾灌注含5x 109>pfu Adanti-ERK2的HTK液0.5 ml.肾移植术后24周行移植肾的病理学观察,免疫组织化学法观察肾小管上皮细胞表面标志蛋白E-Cadherin、Vimentin、TβRⅠ的表达以及CD4+、CD8+T淋巴细胞和ED-1+细胞的浸润情况;酶联免疫法检测受者血清中转化生长因子β1>(TGF-β1>)的含量.结果 肾移植术后24周,对照组和空载病毒组移植肾呈CAN表现;肾小球硬化,肾小管萎缩明显,伴严重间质纤维化以及明显的CD4+、CD8+T淋巴细胞和ED-1+细胞浸润;病变区肾小管上皮细胞E-Cadherin表达减少,Vimentin、TβRⅠ表达显著增多.基因转染组移植肾间质内仅有少量CD4+、CD8+T淋巴细胞和ED-1+细胞浸润;肾小管上皮细胞E-Cadherin表达正常.对照组和空载病毒组血清中TGF-β1>,含量明显高于基因转染组.结论 Adanti-ERK2基因转染移植肾可减缓CAN的发生,对移植肾具有保护作用.这种保护机制可能与减少炎症细胞的浸润、下调TGF-β1>,等致纤维化因子的表达以及抑制肾小管上皮细胞向间充质细胞的转化有关.