A novel CD154 monoclonal antibody in acute and chronic rat vascularized cardiac allograft rejection

BACKGROUND: The CD40-CD154 interaction is critically important in the cell-mediated immune responses. Blockade of this costimulatory pathway has been shown to prevent acute allograft rejection in murine, as well as nonhuman primate models. However, the role of the CD40-CD154 pathway in the development of chronic rejection and the effects of CD154 targeting on progression of chronic rejection have not been evaluated. METHODS: We examined the effect of AH.F5, a new hamster anti-rat CD154 monoclonal antibody, in a fully allogeneic acute(u) into Lewis [LEW] (RT11) and chronic [WF.1L (RT1l) into LEW (RT1l)] vascularized cardiac allograft rejection model. In the chronic model, the antibody was evaluated for prevention (starting day of transplant) and interruption of progression (starting day 30 or 60 after transplant) of chronic vasculopathy. Graft survival, morphology, and immunohistology were evaluated. RESULTS: In the acute rejection model, anti-CD154 therapy alone prevented acute allograft rejection and resulted in 50% long-term allograft survival (>200 days) and donor-specific tolerance. In recipients treated with anti-CD154 monoclonal antibody in combination with a short course of cyclosporine, 100% of allografts survived long-term and all recipients achieved donor-specific tolerance. In the chronic rejection model, allografts from animals treated with the anti-CD154 antibody had a statistically significant lower score of graft arteriosclerosis and fibrosis in both the prevention and 30-day interruption groups when compared with control allografts. In addition, immunohistochemistry showed a decrease in intragraft mononuclear cell infiltration and activation. CONCLUSION: A new anti-CD154 antibody not only prevents acute allograft rejection, but also inhibits and interrupts the development of chronic rejection. In the acute rejection model cyclosporine acts synergistically with anti-CD154 therapy to prolong allograft survival and induce tolerance. In the chronic rejection model relatively early initiation of therapy is essential to prevent progression of chronic allograft vasculopathy and fibrosis.     

Treatment of acute renal allograft rejection with monoclonal anti-T12 antibody

Nineteen patients with acute rejection of a renal allograft were treated with the monoclonal antibody anti-T12, directed against a determinant present on all post-thymic T cells. Seven patients had a good response, four had an equivocal response, and eight failed to respond. Histologic studies demonstrated that the good responders had primarily cellular rejection. The nonresponders included 4 patients with moderate-to-severe humoral rejection, one patient with an inadequate dose of antibody, one patient who withdrew before completing the study, and one patient with late end-stage rejection. All eleven patients with good or equivocal responses have functioning kidneys in a follow-up of 1-15 months (mean 7 months). Only one patient has had a subsequent acute rejection episode, which responded to a steroid pulse. No significant complications of anti-T12 therapy occurred.     

Use of OKT3 monoclonal antibody in the treatment of acute cardiac allograft rejection

OKT3 is a murine monoclonal antibody that recognizes the T3 surface antigen present on mature T cells, and it has been used to successfully treat renal allograft rejection. We report our experience with OKT3 in the treatment of cardiac allograft rejection. Eight patients with endomyocardial biopsy evidence of moderate or severe rejection were given fourteen daily intravenous treatments of OKT3. Six of the eight patients had complete recovery following OKT3 therapy; one required additional steroid therapy for recurrence and one patient failed to respond. Five of the six patients with a complete response have experienced no further rejection (mean follow-up 437 days). Adverse reactions to OKT3 were common early in the treatment course, but were well tolerated. We concluded that OKT3 is a safe and effective treatment of cardiac allograft rejection and that a majority of patients experience long-term rejection-free periods.     

A comparison of OKT3 monoclonal antibody and corticosteroids in the treatment of acute renal allograft rejection

The monoclonal antibody OKT3 (Ortho Pharmaceutical, Raritan, NJ) was utilized in two separate protocols for treatment of acute renal allograft rejection in patients receiving cyclosporine, azathioprine, and prednisone for maintenance immunosuppression. In Group I, 54 patients received steroids for primary treatment of acute rejection with OKT3 used for resistant rejections and second rejection episodes. In Group II, 34 patients received OKT3 as primary treatment of acute rejection while steroids were used for rescue and second rejection episodes. OKT3 successfully reversed 82% of initial acute rejection episodes in Group II as compared with a 63% reversal with steroids in Group I. Rescue treatment was required in only 15% of Group II patients compared with 33% of Group I patients. Overall patient survival was 96% and 94%, respectively, for steroid primary and OKT3 primary treatments. Allograft survival at 3 months was identical, 74% in both groups. Based on allograft survival data, OKT3 is equally effective either as primary treatment for allograft rejection, or for rescue therapy if initial corticosteroid treatment fails.     

CD25单克隆抗体影响心脏移植排斥反应及细胞因子表达的实验研究

目的研究抗白细胞介素-2受体(CD25)单克隆抗体参与大鼠心脏移植排斥反应及调节细胞因子(CK)表达的作用及其机制.方法建立大鼠颈部心脏移植动物试验模型,实验动物随机分为4组,分别单独或联合应用环孢霉素A(CysA)及CD25单克隆抗体(舒莱)来干预心脏移植排斥反应,观察其供心存活时间,并应用RT-PCR的方法检测移植物局部CK如白细胞介素(IL)-1β、IL-2、CD25、IL-4、IL-5、IL-6、IL-10、肿瘤坏死因子(TNF)-α、干扰素(IFN)-γ在移植术后1、3、5、7、9、11和14d 动态表达水平的动态变化.结果 B、C、D组移植心存活时间显著延长,分别为(26.4±5.7)、(29.2±7.1)、(55.0±11.6)d,尤以CysA+舒莱组最显著(P<0.05).CD25的表达在各组中的变化较为明显,在用药组明显降低(P<0.05);IL-4、IL-5、IL-6、IL-10的表达在移植心延长组较强,而IL-2、CD25、IFN-γ、TNF-α的表达则相对较弱.各组细胞因子(CK)表达的高峰时期均与移植物的存活时间及病理变化有一定的关系.结论CK表达在移植排斥反应中发生了相应的变化,并与干预的因素及移植物存活时间有密切的关系,其作用机制多样.二联用药对整个CK网络的作用方式是TH1类CK向TH1类CK整体偏离,而这是这种免疫偏离的机制使本组移植心存活时间延长最显著.     

Detection of cardiac allograft rejection and myocyte necrosis by monoclonal antibody to cardiac myosin

Indium 111-labeled monoclonal antibody to cardiac myosin was examined for efficacy in the detection of cardiac graft rejection and rejection-related myocyte necrosis. Heterotopic heart transplants were performed in isogenic and allogenic groups of rats (n = 56). At selected intervals posttransplant, uptake of injected antibody in the donor and native hearts was determined by gamma scintillation scanning. Indium uptake was compared to histologic results graded for the severity of rejection and the presence of myocyte necrosis. The donor heart uptake of labeled antibody was significantly greater in both moderate rejection and severe rejection than in lesser degrees of rejection (P = 0.05). The donor/native heart antibody uptake ratio (AUR) in both severe and moderate rejection were significantly different from no or mild rejection (P = 0.05). In pooled grafts without myocyte necrosis, both the absolute donor heart antibody uptake and the donor/native heart AUR were significantly greater in grafts with moderate or severe rejection than in those with no or mild rejection (P less than 0.001). Among grafts with moderate or severe rejection, those with myocyte necrosis had greater donor heart antibody uptakes and greater donor/native heart AUR than grafts without myocyte necrosis (P less than 0.001). The grade of rejection and the presence of histologic myocyte necrosis appear to be closely related but independent variables, both of which influence antibody uptake. It is concluded that monoclonal antibody to cardiac myosin may be a useful noninvasive tool that could distinguish moderate or severe rejection from lesser degrees of rejection and that could detect the presence of myocyte necrosis.     

Lymphocyte function in patients treated with monoclonal anti-T3 antibody for acute cadaveric renal allograft rejection

We are participating in a multicenter trial testing the efficacy of a murine monoclonal antihuman peripheral T lymphocyte antibody (OKT3.PAN) as immunosuppressive therapy for the treatment of acute cadaveric renal allograft rejection. Although clinical data indicate that administration of this antibody clears the circulating lymphocyte pool of T3-positive cells, some in vitro studies have called into question whether the antibody is indeed lymphocytotoxic. Other in vitro data suggest that the antibody is a potent mitogen. To address these problems and investigate the effect of the antibody on T cell function, we have studied spontaneous blastogenesis, response to the lectins phytohemagglutinin (PHA) and concanavalin A (ConA), and response to donor-specific and non-donor-specific alloantigen in a one-way MLC in 9 patients treated with anti-T3 for acute rejection and 9 steroid-treated controls. Patients cells were harvested with standard techniques and studied after transplantation, but prior to acute rejection, on days 3 and 12 of therapy and 1 week after cessation of therapy. All patients received baseline immunosuppression with azathioprine and steroids. Acute rejection was reversed with alpha T3 antibody (5 mg i.v./day-1 X 14 days) in 8 of 9 patients and in 6 of 9 steroid-treated controls. Spontaneous blastogenesis was not enhanced by anti-T3 nor did it rise during therapy. PHA and Con A responsiveness were dramatically and significantly depressed by therapy with anti-T3 or steroids on days 3 and 12. Although PHA responsiveness rebounded past baseline 1 week after monoclonal therapy, it was depressed compared with the steroid-treated patients. On the other hand, Con A responsiveness was still significantly depressed one week after monoclonal therapy compared with prerejection values or with controls. Response to donor-specific and to non-donor-specific alloantigen was significantly depressed with anti-T3 therapy compared with steroid controls, and it did not rise during therapy. Donor-specific responses tended to be slower in returning to pretreatment values in the OKT3 patients compared with steroid controls. In summary: (1) Anti-T3 antibody did not enhance spontaneous blastogenesis in patients treated for acute rejection; (2) Con A and PHA responses were dramatically depressed by anti-T3 therapy and returned to baseline following different time courses; (3) Non-donor-specific alloresponse and, more important, donor-specific alloresponse, was more depressed--and for longer periods--by anti-T3 than by conventional steroid anti-rejection therapy.(ABSTRACT TRUNCATED AT 400 WORDS)     

The effect of anti-interleukin-2 receptor monoclonal antibody on allograft rejection

During immune response to an allograft, activated T cells express a number of cell surface activation antigens, among them the membrane receptor for the lymphokine interleukin 2 (IL-2). As the IL-2 receptor is not present on resting T cells, it offers an attractive target for potentially specific immunosuppressive therapy. The rat monoclonal antibody M7/20, which binds to the murine IL-2 receptor, was studied for its effect on allograft survival in two H-2-incompatible strain combinations in inbred mice. Treatment with M7/20 for 10 days markedly prolonged survival of vascularized, heterotopic heart allografts in both strain combinations, with indefinite graft survival in 50% of recipients. The same treatment significantly prolonged skin allograft survival in one of the two combinations. The results support the important role of the IL-2 receptor in the mechanism of graft rejection and confirm its suitability as a target for immunosuppressive therapy in transplantation.     

A novel small-molecule compound targeting CCR5 and CXCR3 prevents acute and chronic allograft rejection

BACKGROUND: Chemokines and chemokine receptors are critical in leukocyte recruitment, activation, and differentiation. Among them, CC chemokine receptor 5 (CCR5) and CXC chemokine receptor 3 (CXCR3) have been reported to play important roles in alloimmune responses and may be potential targets for posttransplant immunosuppression. METHODS: Fully major histocompatibility complex (MHC)-mismatched murine cardiac and islet transplant models were used to test the effect in vivo of a novel, small-molecule compound TAK-779 by targeting CCR5 and CXCR3 in acute allograft rejection. An MHC class II mismatched cardiac transplant model was used to evaluate its efficacy in chronic allograft rejection. Intragraft expression of cytokines, chemokines, and chemokine receptors was measured by quantitative real-time polymerase chain reaction and by histological analysis. RESULTS: Treatment of TAK-779 significantly prolonged allograft survival across the MHC barrier in two distinct transplant models. The treatment downregulated local immune activation as observed by the reduced expression of several chemokines, cytokines, and chemokine receptors. Thereby, the recruitment of CD4, CD8, and CD11c cells into transplanted allografts were inhibited. Furthermore, TAK-779 treatment significantly attenuated the development of chronic vasculopathy, fibrosis, and cellular infiltration. CONCLUSIONS: Antagonism of CCR5 and CXCR3 has a substantial therapeutic effect on inhibiting both acute and chronic allograft rejection. CCR5 and CXCR3 are functional in the process of allograft rejection and may be potential targets in clinical transplantation in the future.     

Specific suppression of allograft rejection by soluble class I antigen and complexes with monoclonal antibody

In this experiment, we investigated the effect of daily injection or continuous slow infusion of either DA (MHC haplotype, RT1a) serum or soluble DA class 1 MHC antigen or its complexes with monoclonal antibody on rejection of heterotopic heart allograft in the combination of PVG.RT1a (RT1a) donor into PVG (RT1c) recipient. DA serum delayed significantly both the early and late rejection of PVG.RT1a heart grafts in PVG recipients. Removal of soluble class I MHC antigen from DA serum by affinity chromatography on a monoclonal anti-class I antibody column completely abolished the immunosuppressive effect. Continuous infusion of purified soluble class I antigen from DA rat liver, even from day 4 after heart grafting, induced a significant prolongation of graft survival. This effectiveness was donor-specific and amplified by the mixture of monoclonal anti-class 1 (RT1a) antibody with DA serum--this being induced only by using continuous infusion but not by daily injection. The results indicate that soluble class I antigen can act as a specific immunosuppressive agent in allograft rejection and that its effect is amplified by monoclonal anti-class 1 antibody.     

Different mechanisms of cardiac allograft rejection in wildtype and CD28-deficient mice.

Although CD28 blockade results in long-term cardiac allograft survival in wildtype mice, CD28-deficient mice effectively reject heart allografts. This study compared the mechanisms of allogeneic responses in wildtype and CD28-deficient mice. Adoptive transfer of purified CD28-deficient T cells into transplanted nude mice resulted in graft rejection. However, this model demonstrated that the allogeneic T cell function was severely impaired when compared with wildtype T cells, despite similar survival kinetics. Cardiac allograft rejection depended on both CD4+ and CD8+ T cell subsets in CD28-deficient mice, whereas only CD4+ T cells were necessary in wildtype recipients. These results suggested that CD8+ T cells were more important in CD28-deficient than wildtype mice. In addition to the CD8+ T cell requirement, allograft rejection in CD28-deficient mice was dependent on a sustained presence of CD4+ T cells, whereas it only required the initial presence of CD4+ T cells in wildtype mice. Taken together, these data suggest that CD4+ T cells from CD28-deficient mice have impaired responses to alloantigen in vivo, thus requiring long-lasting cooperation with CD8+ T cell responses to facilitate graft rejection. These results may help to explain the failure to promote graft tolerance in some preclinical and clinical settings.     

Prediction of acute renal allograft rejection in early post-transplantation period by soluble CD30

To evaluate the feasibility of serum sCD30 for prediction of acute graft rejection, we analyzed clinical data of 231 patients, whose serum levels of sCD30 were detected by ELISA before and after transplantation. They were divided into three groups: acute rejection group (AR, n = 49), uncomplicated course group (UC, n = 171) and delayed graft function group (DGF, n = 11). Preoperative sCD30 levels of three groups were 183 +/- 74, 177 +/- 82 and 168 +/- 53 U/ml, respectively (P = 0.82). Significant decrease of sCD30 was detected in three groups on day 5 and 10 post-transplantation respectively (52 +/- 30 and 9 +/- 5 U/ml respectively, P < 0.001). Compared with Group UC and DGF, patients of Group AR had higher sCD30 values on day 5 post-transplantation (92 +/- 27 U/ml vs. 41 +/- 20 U/ml and 48 +/- 18 U/ml, P < 0.001). However, sCD30 levels on day 10 post-transplantation were virtually similar in patients of three groups (P = 0.43). Receiver operating characteristic (ROC) curve demonstrated that sCD30 level on day 5 post-transplantation could differentiate patients who subsequently suffered acute allograft rejection from others (area under ROC curve 0.95). According to ROC curve, 65 U/ml may be the optimal operational cut-off level to predict impending graft rejection (specificity 91.8%, sensitivity 87.1%). Measurement of soluble CD30 on day 5 post-transplantation might offer a noninvasive means to recognize patients at risk of impending acute graft rejection during early post-transplantation period.