Down regulation of CD45 expression on CD4 T cells during acute renal allograft rejection: Evidence of a decline in T suppressor/inducer activity

Acute rejection is associated with the activation of helper and cytotoxic cells. A shifting balance between the suppressor/inducer CD45+ CD4+ and T helper/inducer (CD4+CD45–) cells may be responsible for the transition from quiescence to overt rejection. We examined the kinetics of CD45 expression on CD4+ T cells in renal allograft recipients from pretransplant values to acute rejection and after reversal of rejection, searching for a shift in balance between helper/inducer and suppressor/inducer cell subsets. Using two color flow cytometry, the peripheral blood levels of CD4+, CD4+CD45– [T helper/inducer (Thi)], CD4+CD45+ [T suppressor/inducer (Tsi)], CD3+, and CD8+ T cells subsets and their interrelationships, were determined in 49 patients prior to transplantation, and in 10 of them, during acute rejection and after its reversal. Results were analyzed and compared to data obtained from 10 healthy blood donors. Acute rejection was associated with a significant decline in CD45+ CD4+ expression compared to quiescent phase (22% ± 3.7%vs. 26.5% ± 3.2%, p = 0.05) and controls (29.5% ± 6.2%, p = 0.01). No difference was observed compared to pretransplant levels (19.9% ± 3.2%, p = ns). CD45–/CD45+ (Thi/Tsi) ratio was lowest during quiescence (0.75) compared to rejection (0.97, p = 0.05), in controls (0.98, p = 0.05) and pretransplant values (1.4, p = 0.01). Acute rejection was characterized by higher Thi/CD8+ and lower Tsi/CD8+ ratio (103 and 88 respectively, p = 0.045), compared to clinical quiescence (104 and 116 respectively, p = 0.039). These data suggest that acute rejection is associated with down regulation of CD4+CD45+ suppressor/inducer subset. This shift may account for the transition from quiescence to overt rejection, concurring with reports on CD4+CD45 regulatory function.     

大鼠小肠移植后外周血CD45RC+细胞和CD45RC-细胞比值的变化及意义

目的探讨可用于诊断小肠移植后排斥反应的指标.方法采用F334大鼠建立同系全小肠移植模型,以近交系F334大鼠和BN大鼠建立同种全小肠移植模型,术后采用流式细胞仪连续测定外周血CD4+、CD8+细胞中CD45+亚群以及CD45RC+细胞与CD45RC-细胞比值(CD45RC+/CD45RC-)的变化,同期进行移植肠组织病理学检查.结果同系移植组受者术后均获长期存活(＞28 d);同种移植组受者术后存活(12.0±1.3)d,出现中、重度排斥反应.术后外周血CD4+CD45+和CD8+CD45+细胞的变化,两组间的差异无统计学意义;同系移植组CD4+CD45RC+/CD4+CD45RC―及CD8+CD45RC+/CD8+CD45RC―在术后3 d升高,然后迅速降至手术当天的水平,同种移植组上述指标术后均维持较高水平.结论动态观察CD4+CD45RC+/CD4+CD45RC-较适于监视排斥反应的发展过程,而CD8+CD45RC+/CD8+CD45RC-更适于排斥反应的早期诊断.     

Pretreatment of kidney allografts with monoclonal antibodies to CD 45: results of a multicentre study

Abstract The perfusion of human renal allografts with CD45-pecific monoclonal antibodies (mAbs) may reduce their immunogenicity and the incidence Of rejection. we performed a safety study in 40 patients receiving their first cadaveric renal transplant. Two milligrams each of the rat CD 45 specific mAbs YTH 24.5 and YTH 54.12 were perfused into the grafts prior to transplantation. The patients were followed for 3 months. No patient died, and four grafts were lost, three to vascular causes not considered to be related to antibody perfusion and one to severe rejection. Two patients developed an anti-rat antibody response. Immunohistological double-labelling performed on cortical biopsies taken post-perfusion and prior to wound closure showed that at least 60% of the CD 45+ cells were coated by perfused anti-CD 45 ('antibody uptake'). Among the patients studied for uptake and episodes of rejection, the incidence of rejection was 75% in 12 patients whose antibody uptake was < 95% compared with 22% in 18 patients with antibody uptake 2 95% ( P = 0.01). We conclude that this treatment was free of adverse effects and that there is a correlation between the uptake of antibody by passenger leucocytes and reduction in acute rejection episodes.     

Analysis of Human Biologics With a Mouse Skin Transplant Model in Humanized Mice

Preclinical testing of human therapeutic monoclonal antibodies has been limited in murine models due to species differences in pharmacokinetics and biologic responses. To overcome these constraints we developed a murine skin transplant model in humanized mice and used it to test human monoclonal antibody therapy. Neonatal NOD/SCID/IL2Rγc^null mice (NSG) were reconstituted with human CD34⁺ hematopoietic stem cells (hNSG). When adult, these mice rejected MHC mismatched murine C57BL/6J skin grafts. Rejection required adequate reconstitution with human cells. There was diffuse infiltration of the epidermis and dermis with hCD8 and hCD4 cells in rejected grafts by immunohistochemistry. Studies with B6/MHC class I and II knockout mice donors indicated that neither is required for rejection. Graft rejection was associated with the development of effector and central memory T cells and an increase in serum immunoglobulins. We also tested the effects of teplizumab (anti‐CD3 mAb) and found it could delay skin graft rejection, whereas ipilimumab (anti‐CTLA‐4 [cytotoxic T‐lymphocyte antigen‐4] mAb) treatment accelerated rejection. These findings demonstrate that hNSG mice reliably and predictably reject a xenogenic mouse skin graft by a human T cell mediated mechanism. The model can be utilized to investigate the ability of human immunotherapies to enhance or suppress functional human immune responses.     

Acute Cellular Rejection Predominated by Monocytes Is a Severe Form of Rejection in Human Renal Recipients With or Without Campath-1H (Alemtuzumab) Induction Therapy

Campath-1H has been used successfully for induction and has resulted in a low rate of acute cellular rejection (ACR) in renal transplantation in combination with various postoperative immunosuppression regimens. This study was undertaken to investigate the extent of monocyte involvement in ACR, with or without Campath-1H induction. We found that monocytes represented the majority of inflammatory cells in grades Ib or higher ACR, but not with Ia type of ACR, regardless of the status of Campath-1H induction. Cases of ACR, following Campath-1H induction, appear to demonstrate a 'pure form' of monocytic ACR, whereas monocytes were mixed with many other types of inflammatory cells in the cases of ACR in the absence of Campath-1H induction. In addition with Campath-1H induction, the cases of monocyte-predominant ACR were found to uniformly exhibit a good response to corticosteroid treatment. We conclude that monocyte-predominate ACR may represent a severe form of rejection, with or without Campath-1H treatment.     

Inhibition of CD1d activation suppresses septic mortality: a role for NK-T cells in septic immune dysfunction

BACKGROUND: Studies indicate that following septic insult there is development of generalized immune dysfunction in T cells, B cells and phagocytes, which is thought to contribute to morbidity and mortality. Specifically, there is a shift in the lymphocytes of septic animals toward an increased release of Th2 cytokines. NK-T cells have been shown to contribute to propagation of the Th2 response. The influence of NK-T cells on the immune response to septic challenge is poorly understood. In this study, we examine whether NK-T cells contribute to the immune dysfunction seen following the onset of polymicrobial sepsis, as produced by cecal ligation and puncture (CLP). MATERIALS AND METHODS: Male 129S1/SvImJ mice were pretreated with either rat IgG (isotypic control) or monoclonal antibody to CD1d (clone 1B1) (0.5 mg), which blocks signaling/antigen presentation via the CD1d cell surface receptor, thereby, ablating the activation and differentiation of the NK-T cells. Septic survival with and without anti-CD1d (CLP/CD1d) pretreatment was assessed. Mice sacrificed 24 h after CLP were assessed for change in splenic %NK-T cell (via flourescense activated cell sector) and for splenic, hepatic, and lymphoid/macrophage production of pro-inflammatory or anti-inflammatory cytokines (via enzyme-linked immunosorbent assay). RESULTS: Administration of anti-CD1d reduced septic mortality 35% at 6-10 d (n = 23 mice/group) (P <.05). There was a consistent increase in the %CD3(+) NK1.1(+) cell population (NK-T cells) in septic mice (1.706%), which was markedly suppressed by pretreatment with anti-CD1d (0.592%). IL-6 and IL-10 levels were suppressed by anti-CD1d in the spleen and blood. CONCLUSIONS: Together these findings imply not only that NK-T cells may play a role in mediating the immune suppression seen in bacterial sepsis, but that inhibition of their activation promotes survival to septic challenge.     

The Introduction of Human Heme Oxygenase‐1 and Soluble Tumor Necrosis Factor‐α Receptor Type I With Human IgG1 Fc in Porcine Islets Prolongs Islet Xenograft Survival in Humanized Mice

Apoptosis during engraftment and inflammation induce poor islet xenograft survival. We aimed to determine whether overexpression of human heme oxygenase‐1 (HO‐1) or soluble tumor necrosis factor‐α receptor type I with human IgG₁ Fc (sTNF‐αR‐Fc) in porcine islets could improve islet xenograft survival. Adult porcine islets were transduced with adenovirus containing human HO‐1, sTNF‐αR‐Fc, sTNF‐αR‐Fc/HO‐1 or green fluorescent protein (control). Humanized mice were generated by injecting human cord blood–derived CD34⁺ stem cells into NOD‐scid‐IL‐2Rγ^null mice. Both HO‐1 and sTNF‐αR‐Fc reduced islet apoptosis under in vitro hypoxia or cytokine stimuli and suppressed RANTES induction without compromising insulin secretion. Introduction of either gene into islets prolonged islet xenograft survival in pig‐to‐humanized mice transplantation. The sTNF‐αR‐Fc/HO‐1 group showed the best glucose tolerance. Target genes were successfully expressed in islet xenografts. Perigraft infiltration of macrophages and T cells was suppressed with decreased expression of RANTES, tumor necrosis factor‐α and IL‐6 in treatment groups; however, frequency of pig‐specific interferon‐γ–producing T cells was not decreased, and humoral response was not significant in any group. Early apoptosis of islet cells was suppressed in the treatment groups. In conclusion, overexpression of HO‐1 or sTNF‐αR‐Fc in porcine islets improved islet xenograft survival by suppressing both apoptosis and inflammation. HO‐1 or sTNF‐αR‐Fc transgenic pigs have potential for islet xenotransplantation.     

CD44v6在大肠癌中的表达与转移及预后的关系

为探讨ＣＤ４４ｖ６表达与大肠癌转移及预后的关系，对１０１例大肠癌存档石蜡组织标本进行重新切片，采用ＣＤ４４ｖ６鼠单克隆抗体进行免疫组化染色（ＬＳＡＢ法）。结果发现ＣＤ４４ｖ６表达与年龄、性别、肿瘤大小、部位、组织类型无关；与Ｄｕｋｅｓ分期、淋巴结转移、其它脏器转移和根治术后复发有关；ＣＤ４４ｖ６表达阳性者术后生存率较表达阴性者低（Ｐ＜０．０１）。结果表明：ＣＤ４４ｖ６在大肠癌转移和复发中具有一定的作用，可能成为预测大肠癌转移和预后的生物学指标之一。