Increased CD4+ CD25+ T regulatory cell activity in trauma patients depresses protective Th1 immunity

OBJECTIVES: We recently reported increased CD4 CD25 T regulatory (Treg) activity after burn injury in mice. This study sought to determine if Tregs mediate the reduction in TH1-type immunity after serious injury in man and if Treg function is altered by injury. METHODS: Peripheral blood was withdrawn from 19 consenting adult patients (35.1 +/- 16.3 years of age) with Injury Severity Scores (ISS) 36.6 +/- 13.9 on days 1 and 7 after trauma and from 5 healthy individuals. CD4 T cells were purified and sorted into Treg (CD25(high)) and Treg-depleted populations. After activation of cells with anti-CD3/CD28 antibody, production of the TH1-type cytokine IFNgamma, TH2-type cytokines (IL-4 and IL-5), and the inhibitory cytokine IL-10 was measured using cytometric bead arrays. Treg activity was measured by in vitro suppression of autologous CD4 T cell proliferation. RESULTS: All patients survived, 9 (47%) developed infection postinjury. IFNgamma production by patient CD4 T cells was decreased on day 1 and day 7, when compared with healthy controls. However, when Tregs were depleted from the CD4 T cells, the IFNgamma production increased to control levels. Tregs were the chief source of IL-4 and IL-5 as well as IL-10. Treg suppression of T cell proliferation increased significantly from day 1 to day 7 after injury. CONCLUSIONS: We demonstrate for the first time that human Tregs are increased in potency after severe injury. Most significantly, Tregs are important mediators of the suppression of T cell activation and the reduction in TH1 cytokine production found after injury.     

Acute lung transplant rejection is associated with localized increase in T-cell IFNgamma and TNFalpha proinflammatory cytokines in the airways

BACKGROUND: Allograft rejection remains a major cause of morbidity and mortality after lung transplantation and is associated with increased gene expression for proinflammatory cytokines. T cells are a major cell type involved in graft rejection. There have been no previous studies of cytokine production by T cells from blood, bronchoalveolar lavage (BAL), and intraepithelial T cells from bronchial brushings (BB) during rejection episodes; we hypothesized that T-cell proinflammatory cytokines would be increased in the airways during rejection episodes despite standard immunosuppression regimens. METHOD: To investigate changes in cytokine profiles during rejection episodes, whole blood, BAL, and BB from stable lung transplant patients and those with acute rejection were stimulated in vitro and intracellular cytokine production by CD8- (CD4+) and CD8+ T-cell subsets determined using multiparameter flow cytometry. RESULTS: Transforming growth factor (TGF)-beta was significantly decreased in blood CD4+ and CD8+ T cells while interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha were significantly increased in BAL CD4+ and CD8+ T cells in patients with evidence of rejection. There was no change in CD4:CD8, interleukin (IL)-2, or IL-4 between stable and rejecting groups. CONCLUSIONS: Acute lung transplant rejection is associated with decreased intracellular T-cell TGFbeta in blood and increased intracellular IFNgamma and TNFalpha in BAL CD4+ and CD8+ T cells. Drugs that effectively reduce airway T-cell IFNgamma and TNFalpha proinflammatory cytokine production may improve current protocols for reducing acute graft rejection in lung transplant patients.     

Increased intracellular pro- and anti-inflammatory cytokines in bronchoalveolar lavage T cells of stable lung transplant patients

BACKGROUND: Allograft rejection remains a major cause of morbidity and mortality following lung transplantation and is associated with an increased expression of T-cell proinflammatory cytokines. We have recently shown that peripheral blood T-cell proinflammatory cytokine production was significantly reduced in stable lung transplant patients consistent with immunosuppression therapy. However, analysis of inflammatory cytokine profiles in bronchoalveolar lavage (BAL) T cells may be more relevant than peripheral blood T cells for assessing graft status. METHODS: To investigate the immunomodulatory effects of currently used immunosuppressive regimens on BAL T-cell cytokine production, whole blood and BAL from stable lung transplant patients and control volunteers was stimulated in vitro and cytokine production by CD8+ and CD4+ T-cell subsets determined using multiparameter flow cytometry. RESULTS: There was a significant decrease in T-cell proinflammatory cytokine production in BAL compared with blood from control subjects but not transplant patients. Anti-inflammatory cytokine IL-4 was increased in BAL compared with blood from both groups. There was a significant increase in IFNgamma, IL-2, IL-4, TGFbeta, and TNFalpha production by CD8 T cells and IFNgamma and TNFalpha production by CD4 T cells in BAL from transplant patients compared with controls. CONCLUSIONS: We have shown decreased T-cell pro- and anti-inflammatory cytokine production in BAL compared with blood in control subjects but not in stable lung transplant patients. Current immunosuppression protocols have limited effect on T-cell proinflammatory cytokine production in BAL but do upregulate anti-inflammatory cytokines IL-4 and TGFbeta. Drugs that effectively reduce T-cell proinflammatory cytokine production in BAL may improve current protocols for reducing graft rejection in these patients.     

T cell deletion and unresponsiveness induced by intrathymic injection of staphylococcal enterotoxin B

Intrathymic injection of alloantigens appears to be the most efficient route to induce alterations of T cell reactivity. In the present study, we explored the modifications of Vbeta8.1, 8.2 T cell population and T cell reactivity in the thymus and in the spleen induced by intrathymic injection of staphylococcal enterotoxin B to adult mice. Vbeta8 antigen expression was investigated by flow cytometry analysis. T Cell reactivity was studied in vitro by the proliferative response to SEB. SEB induced a significant reduction in the percentage of mature Vbeta8+ T cells in the thymus (days 7-14), and in the spleen (days 7-28). Interestingly, this depletion occurs in the CD4- CD8+ cells in the thymus whereas in the CD4+ CD8- cells in the spleen. In parallel, the proliferative response to SEB but not to SEA was significantly decreased in the thymus on days 7 and 14, and in the spleen from day 7 to day 28. Moreover, this unresponsiveness was more pronounced in the spleen than in the thymus. Anergy was SEB-specific and fully reversed by exogenous IL-2. SEB injected intrathymically induced significantly more pronounced and more durable T cell alterations than intraperitoneal and subcutaneous injections. This may be related to the observation that after i.t. injection, SEB was detected both at a higher amount and for a longer period in the central and peripheral compartments. Our results clearly demonstrate that the intrathymic route is definitely the most efficient to induce not only thymic but also peripheral pivotal immune alterations in our model.     

Contrasting Alloreactive CD4+ and CD8+ T Cells: There''s More to It Than MHC Restriction

Surface expression of CD4 or CD8 is commonly used to identify T-cell subsets that recognize antigen presented by class II MHC or class I MHC, respectively. This holds true for T cells that respond to allogeneic MHC molecules that are directly recognized as foreign, as well as peptides from allogeneic MHC molecules that are indirectly presented by self MHC molecules. CD4 or CD8 expression was initially believed to define cytokine secreting helper T cells or cytotoxic cells, respectively. However, this association of phenotype and function is not absolute, in that CD4+ cells may possess lytic activity and CD8+ cells secrete cytokines, notably IFNgamma. Recently, additional fundamental differences in the immunobiology of these T-cell subsets have been identified. These include differences in costimulatory requirements, cytokine responsiveness, cytokine production, cell survival, and the maintenance of memory. This review will survey these differences, emphasizing alloreactive T-cell responses as well as relevant observations that have been made in other systems.     

Apoptosis of superantigen-activated T cells induced by mycophenolate mofetil treatment

BACKGROUND: Mycophenolate mofetil (MMF), an ester prodrug of mycophenolic acid (MPA), is a potent immunosuppressive agent used in clinical organ transplantation. MPA preferentially inhibits the type II isoform of inosine monophosphate dehydrogenase, depletes GTP, suppresses transfer of mannose and fucose to glycoproteins, and prevents lymphocyte proliferation in vivo. Whether MMF can also delete activated T cells in vivo by triggering an apoptotic signal was addressed in this study. To this end we analyzed the activity of MMF in mice injected with the bacterial superantigen staphylococcal enterotoxin B (SEB). Superantigens bind to MHC class II molecules without requirement for processing, and activate subsets of CD4+ and CD8+ T cells whose T cell receptor beta chains express Vbeta family-specific homologous sequences. This model that shares several features with direct allorecognition has the unique advantage of allowing a precise monitoring of activated T cells. METHODS: BALB/c mice treated with MMF (100 mg/kg/ day) or vehicle were injected with SEB. Serum cytokines, CD4+ and CD8+ Vbeta8+ cells were monitored in blood and lymphoid tissues, and apoptosis was determined by externalization of membrane phosphatidyl serine, double strand DNA breaks, and expression of B220 antigen by Vbeta8+ cells. RESULTS: MMF treatment decreased tumor necrosis factor alpha, interferon gamma, and interleukin-10 secretion induced by SEB. It did not modify other early activation events (blast transformation, CD69 and CD25 expression) but completely inhibited SEB-induced expansion of Vbeta8+ cells by inducing apoptosis of SEB-reactive T cells. A similar effect was observed in CD95-ligand-deficient mice. Repeated SEB injections associated with MMF resulted in a marked decrease of CD8+ Vbeta8+ T cells. SEB-induced increase of Vbeta8+ thymocytes was not prevented by MMF treatment. CONCLUSION: Results obtained in this in vivo model suggest that MMF treatment may induce deletion of activated peripheral T cells and decrease early cytokine responses.     

Th1/Th2 balance in childhood idiopathic nephrotic syndrome

AIMS: In view of the conflicting evidence of helper T cell type 1 (Th1) or type 2 (Th2) pattern of cytokine synthesis in childhood idiopathic nephrotic syndrome (INS) this study examined the balance of Th1 and Th2 which are characterized by intracellular cytokine production of interferon-gamma (IFNgamma) and interleukin-4 (IL-4), respectively. SUBJECTS AND METHODS: Sixteen children with steroid-sensitive INS (mean age 9.0 years) were included in this study, together with 15 healthy normal children (mean age 7.9 years) for the control group. Intracellular production of both IFNgamma and IL-4 in helper T cell (CD4+ cell) was investigated by a 3-color flow cytometry. RESULTS: The cross-sectional data showed no significant differences of percentages of Th0 (IFNgamma+ IL-4+ CD4+ cell), Th1 (IFNgamma+ lL-4- CD4+ cell) and Th2 (IFNgamma- IL-4+ CD4+ cell) in CD4+ cells (p > 0.05). The Th1/Th2 ratio during nephrotic relapse did not differ from those during nephrotic remission and in normal healthy children (p > 0.05). CONCLUSION: We conclude that there is no significant skew of Th1/Th2 balance in childhood INS and that the cardinal immunological abnormality does not lie in helper T cells but in other cells, such as suppressor/cytotoxic T cells, natural killer cells or monocytes/macrophage. To clarify the pathogenesis of INS, comprehensive studies for these cells would be worthwhile.     

Relationships between regulatory T cells and CD8+ effector populations in patients with squamous cell carcinoma of the head and neck

BACKGROUND: Homeostasis of circulating T cells is regulated in complex ways that have not yet been well defined. The balance between type 1 and type 2 T-cell subsets in cancer patients is thought to modulate antitumor immunity. Meanwhile, CD4+CD25+ regulatory T cells (Treg), which are potent inhibitors of antitumor immune responses, also play an invaluable role in maintaining immune homeostasis. METHODS: Peripheral blood was obtained from 42 patients with squamous cell carcinoma of the head and neck (SCCHN) and 24 healthy age-selected donors. The percentages of T-cell subsets and their cytokine profiles expressed in response to ex vivo stimulation were studied by multicolor flow cytometry. RESULTS: Although patients with SCCHN had a lower percentage (p < .05) of circulating CD4+ T cells than healthy donors, CD4+CD25+ regulatory T cells (Treg) were increased in the patients (p < .01). A significant increase in Th1 and Th2 CD4+ T cells was observed in the patients after ex vivo stimulation with phorbol 12-myristate 13-acetate /ionomycin. The percent of Treg inversely correlated with that of total CD8+ T cells (p < .05), CD8+IFN-gamma+ (Tc1) cells (p < .05), and CD8+IL-4+ (Tc2) cells (p < .01). There was a highly significant correlation between Tc1 and Tc2 CD8+ T cells (p < .0001) in SCCHN patients but not in controls. CONCLUSIONS: Treg are increased in proportion in the circulation of patients with SCCHN. These cells appear to downregulate cytokine expression in both Tc1 and Tc2 subsets of CD8+ effector T cells, which may be responsible for antitumor responses.     

Rapamycin does not induce anergy but inhibits expansion and differentiation of alloreactive human T cells

BACKGROUND: Studies in mice have shown that rapamycin inhibits cell cycle progression and promotes the development of clonal anergy. We here addressed the question if rapamycin can induce anergy of human T cells and studied the effects of rapamycin on activation, proliferation and expression of cytotoxic effector molecules of alloresponsive T cells in mixed lymphocyte cultures. METHODS: Peripheral blood mononuclear cells from healthy individuals were labeled with CFSE to monitor subsequent cell divisions. Cells were cocultured with allogeneic irradiated cells in the presence or absence of rapamycin. Flowcytometric analysis was performed after staining for surface CD4, CD8, and CD25 and for intracellular perforin, granzyme B, active caspase-3, and TGF-beta. Bio-Plex cytokine assay was done to measure the secretion of IL-2, IL-4, IL-10, and IFN-gamma. RESULTS: Addition of rapamycin at a final concentration of 10 ng/ml strongly decreased precursor frequencies of alloreactive CD4+ and CD8+ T cells. However, when these cells were washed and subsequently specifically restimulated in the absence of rapamycin, the proliferative capacity appeared normal. Next to lowering precursor frequencies, rapamycin also inhibited T cell expansion by inducing apoptosis in divided alloreactive CD4+ and CD8+ T cells. Rapamycin did not interfere with the formation of CD25brightCD4+ T cells during allogeneic stimulation and did not inhibit their suppressive function. Furthermore, the drug decreased production of effector molecules perforin and granzyme B by alloreactive T cells and diminished alloreactive cytotoxicity. CONCLUSION: Our data show that rapamycin strongly inhibits proliferation and effector functions of alloreactive T cells in vitro, but does not induce alloantigen specific nonresponsiveness.     

Variation and significance of NKT cell and its subset in patients with severe multiple injuries

Objective: To observe the variation and significance of natural killer T (NKT) cells in patients with severe multiple injuries. Methods: Peripheral blood was drawn from 30 patients with severe multiple injuries and 20 healthy individuals. NKT cells and the subsets of NKT cells were stained and analyzed on fluorescence activated cell sorter (FACS) using Cellquest software. The level of IL-4 and IFN-γ in blood serum was detected by ELISA. Results: The proportion of NKT cells was significantly increased. CD4+ NKT cells was increased (t=-3.11, P<0.01) and CD4+CD8+NKT (double negative NKT, DN NKT) cells decreased in patients with severe multiple injuries compared with healthy controls (t=2.99, P<0.01). There was a positive correlation between the proportion of NKT cells and injury severity score (ISS) by Spearman correlation analysis (r=0.70, P<0. 01). The level of IFN-γ was significantly decreased and the level of IL-4 significantly increased in patients with severe multiple injuries. Conclusions: We demonstrate that human NKT cells are increased in trauma patients. Most significantly, there is an association between ISS and NKT cells. The increased CD4+ NKT cells may contribute to the reduction of Th1 cytokine production and the growth of Th2 cytokine production, leading to the suppression of immunity after injury.     

Major injury induces increased production of interleukin-10 by cells of the immune system with a negative impact on resistance to infection.

OBJECTIVE: The purpose of this study was to compare the production of interleukin-10 (IL-10) by peripheral blood mononuclear cells (PBMC) from injured patients and control subjects to determine the responsible cell types and to relate IL-10 production to the occurrence of sepsis. A mouse model of burn injury was used to confirm the human findings and to assess the importance of IL-10 in the lowered resistance to infection after injury. SUMMARY BACKGROUND DATA: Severe injury is associated with depressed immune responses. Although IL-10 is known to inhibit several aspects of immune reactivity, the role of IL-10 in postinjury immune suppression remains controversial. METHODS: Peripheral blood mononuclear cells from 14 burn and 12 trauma patients and 16 healthy individuals were studied at serial intervals for IL-10 production stimulated by a T-cell mitogen, phytohemagglutinin, and by bacterial lipopolysaccharide. To determine the source of IL-10, CD4+ and CD8+ lymphocyte subsets were obtained by selective depletion of PBMC with antibody-coated magnetic beads and were stimulated by anti-CD3 antibody to induce IL-10 secretion. In addition, IL-10 production by patients' PBMC in the first 10 days after injury was assessed for correlation with subsequent septic events. Anti-CD3-stimulated IL-10 production also was determined for CD4- and CD8-enriched lymphocyte subsets obtained by antibody and complement depletion of splenocytes harvested from groups of burn and sham burn mice at day 10 after injury, the time of maximal susceptibility to a septic challenge, cecal ligation and puncture (CLP). Finally, to test the importance of IL-10 in immune suppression in vivo, groups of burn and sham burn mice were treated with anti-IL-10 monoclonal antibody or control immunoglobulin G (IgG) on days 1 and 3 postinjury and were observed for survival after CLP on day 10. RESULTS: Patients' PBMC produced significantly more IL-10 than did controls' PBMC 7 to 14 days after injury. Patients' CD4+ (T-helper) but not CD8+ (T-cytotoxic) lymphocytes also showed increased IL-10 production versus those of control subjects early after injury. Increased PBMC IL-10 production in the first 10 days postinjury correlated significantly (p < 0.05) with subsequent septic events. Burn mouse CD4-enriched but not CD8-enriched splenocytes produced more IL-10 than did sham burn splenocyte subsets on day 10 after injury. Burn mice treated with anti-IL-10 antibody but not with control IgG had significantly increased survival after CLP. CONCLUSION: Serious injury in humans and in a mouse burn model is followed by increased stimulated production of IL-10 by cells of the immune system. The CD4+ T-helper cells appear to be a major source of IL-10 after injury. In injured patients, increased IL-10 production is correlated with subsequent septic events, and in the burn mouse, IL-10 appears to induce decreased resistance to infection.     

Inducible co-stimulatory molecule ligand is protective during the induction and effector phases of crescentic glomerulonephritis

The inducible co-stimulatory molecule (ICOS)/ICOS ligand (ICOSL) co-stimulatory pathway is critical in T cell activation, differentiation, and effector function. Its role was investigated in a model of Th1-driven crescentic glomerulonephritis (GN). GN was induced by sensitizing mice to sheep globulin (day 0) and challenging them with sheep anti-mouse glomerular basement membrane antibody (Ab; day 10). Disease and immune responses were assessed on day 20. For testing the role of ICOSL in the induction of GN, control or anti-ICOSL mAb were administered from days 0 to 8. For examining the role of ICOSL in the effector phase of GN, treatment lasted from days 10 to 18. Blockade of ICOSL during the induction of GN increased glomerular accumulation of CD4+ T cells and macrophages and augmented renal injury. These results correlated with attenuated splenocyte production of protective Th2 cytokines IL-4 and IL-10 and decreased apoptosis of splenic CD4+ T cells. ICOSL was upregulated within glomeruli of mice with GN. Inhibition of ICOSL during the effector phase of GN enhanced glomerular T cell and macrophage accumulation and augmented disease, without affecting the systemic immune response (cytokine production, T cell apoptosis/proliferation, Ab levels). Increased presence of leukocytes in glomeruli of mice that received anti-ICOSL mAb was associated with enhanced cellular proliferation and upregulation of P-selectin and intercellular adhesion molecule-1 within glomeruli. These studies demonstrate that ICOSL is protective during the induction of GN by augmenting Th2 responses and CD4+ T cell apoptosis. They also show that ICOSL is upregulated in nephritic glomeruli, where it locally reduces accumulation of T cells and macrophages and attenuates renal injury.     

移植抗原特异性转基因CD8+T细胞对白细胞介素2的依赖性

目的研究白细胞介素2（IL-2）在调节移植抗原特异性转基因CD8^＋T细胞介导的免疫排斥反应中的作用。方法将经荧光染科CFSE标记后的C57BL／6小鼠和2CTg小鼠（CD4敲除鼠）淋巴细胞分别植入经致死剂量γ射线照射过的两组DBA／2J小鼠体内，检测CD4^＋与CD8^＋T细胞在体内分裂增殖的时相，并用胞浆内IL-2标志染色方法测定活化后T细胞表达IL-2的能力。以Balb／c小鼠为供者，糖尿病2CTg小鼠和2C Tg-IL-2KO小鼠（IL-2敲除鼠）为受者，进行胰岛细胞移植。观察CD8^＋ T细胞在介导移植排斥中的作用。结果DBA／2J小鼠输注了C57BL／6小鼠的淋巴细胞后，CD4^＋与CD8^＋T细胞分裂增殖均非常明显，前者表达大量IL-2，后者则不表达。DBA／2J小鼠输注了2CTg小鼠的淋巴细胞后。在完全没有CD4^＋T细胞存在的情况下，CD8^＋T细胞仍明显分裂增殖并大量表达IL-2。2CTg和2CTg—IL-2KO小鼠移植胰岛细胞后，前者迅速发生排斥反应，胰岛移植物的平均存活时间仅为8d，而后者胰岛移植物的平均存活时间〉50d。结论CD8^＋T细胞在产生和利用IL-2时有很大的可塑性。CD4^＋T细胞存在时，CD8^＋T细胞能有效利用CD4^＋T细来源的IL-2进行分裂增殖，在缺乏CD4^＋T细胞时，则利用自身来源的IL-2进行分裂增殖；移植抗原特异性CD8^＋T细胞的效应功能完全依赖于IL-2，排斥反应由CD8^＋T细胞介导时，阻断IL-2／IL-2受体通路可诱导移植物长期存活。     

CD8+ T cell subsets TC1 and TC2 cause different histopathologic forms of murine cardiac allograft rejection

BACKGROUND: CD4+ T cell effector function is sufficient to mediate allograft rejection, and it is suggested that CD8+ T cell-mediated effects are dependent on CD4+ T cell help. CD8+ T cells can be classified into at least two functional subsets: Tc1, producing high amounts of interferon (IFN)-gamma and Tc2, producing interleukin (IL)-4, -5, -10, and -13 and low levels of IFN-gamma. Because these subsets express different chemokine receptors, they may have different capabilities of migrating into grafts. Once in the graft, each subset may perform different effector functions dependent on the cytokines it produces. We asked whether allospecific CD8+ T cells, in the absence of CD4+ T cells, are capable of mediating rejection of a primarily vascularized allograft, and if Tcl and Tc2 cells differ in their ability to mediate rejection. METHODS: Hearts from H-2d mice were transplanted into H-2b RAG 1-/- recipients. Without manipulation, these fully mismatched allografts would survive indefinitely due to the absence of mature T and B cells. We adoptively transferred allo-(H-2d)-reactive Tcl or Tc2 cells from H-2b mice into each recipient. Grafts were harvested and analyzed on predefined timepoints, rejection was graded on a modified ISHLT scale. RESULTS: On day 7, grafts from Tc1- or Tc2-injected animals showed grade 1-2 parenchymal rejection with stable phenotype and comparable distribution of graft infiltrating CD8+ T cells. Adoptive transfer of IFN-gammahigh Tc1, but not of IFN-gammalow Tc2 cells was followed by the development of graft vasculitis, as well as graft arteriopathy. Adoptive transfer of IL-4high IL-5high Tc2, but not of IL-4low IL-5low Tc1 cells lead to extensive infiltration of eosinophils and formation of giant cells. CONCLUSIONS: Both Tc1 and Tc2 cells can mediate murine cardiac allograft rejection in the absence of CD4+ T cell help, although each subset elicits a different type of inflammatory response. In this model, cytokine secretion of either functional CD8+ T effector cell subset is an important effector mechanism in the process of allograft rejection: IFN-gammahigh Tc1 cells are important in early graft vasculitis, although IL-4high IL-5high Tc2 cells promote recruitment of secondary effectors like eosinophils.     

RATG对CD4+细胞和CD8+细胞共刺激分子基因表达和细胞因子分泌的影响

目的 探讨兔抗人胸腺细胞多克隆抗体(RATG)在体外对CD4+细胞和CD8+细胞共刺激分子基因表达和细胞因子分泌的影响.方法 从正常成人外周血单个核细胞中分离和纯化CD4+细胞和CD8+细胞,加入RATG,37℃下培养.分别于24、48和72 h收集培养上清液和细胞,以不处理的细胞为正常对照,正常兔Ig处理的细胞作为阴性对照.采用实时聚合酶链反应技术检测培养细胞的细胞毒性T淋巴细胞相关抗原4(CTLA4)、CD154、Foxp3、OX40、γ干扰素(IFN-γ)、白细胞介素2(IL-2)、IL-10和IL-2受体(CD25)的基因表达水平,应用Multiplex检测技术测定培养上清液中IFIN-γ、IL-2、IL_4和IL-10的水平.结果 与正常CD4+细胞比较,加入RATG的CD4+细胞培养24 h,其CTLA-4、CD154、Foxp3、OX40、IFN-γ、IL-2、IL-10和CD25基因转录表达均上调,阴性对照CD4+细胞则无这些基因转录表达的上调.处理48 h后,CD4+细胞的CD154和IL-2的基因转录表达呈现下调现象,而CTLA4、Foxp3、0X40、IFN-γ、IL-10和CD25的基因转录水平均较24 h时明显降低.处理72 h后,CD4+细胞的CTLA4、Foxp3、OX40和CD25的基因转录表达再次呈现高水平,CD154和IFN-γ的基因转录表达上调表达不明显,而IL-2和IL-10的基因转录表达则呈现明显的下调.RATG处理的CD4+细胞培养上清液中的IFN-γ、IL-2、IL-4和IL-10浓度显著增加,以处理24 h的水平最高,而阴性对照者未测出.与正常CD8+细胞相比较,加入RATG处理的CD8+细胞培养24 h,其CTLA4、Foxp3、OX40、IFN-γ,、IL-2、IL-10和CD25的基因转录表达呈现明显上调,而CD154基因转录表达稍有下调.RATG处理48 h,CD8+细胞的CTLA4、Foxp3、OX40、IFN-γ和CD25基因转录表达仍维持在高水平,CD154基因转录表达仅仅呈现低水平的上调,IL-10基因转录表达水平显著下降,而IL-2的基因转录表达则明显下调.处理72 h,CD8+细胞的CTLA4、Foxp3、OX40、IFN-γ、IL-10和CD25的基因转录表达仍维持在高水平,CD154基因转录表达则呈现下调,而IL-2基因转录表达的下调更为显著.阴性对照CD8+细胞则未呈现这些基因转录的上调现象.RATG处理的CD8+细胞培养上清液中IFN-γ、IL-2和IL-10显著增多,以处理24 h的浓度最高,IL-4浓度升高的幅度较小,而正常CD8+细胞和阴性对照CD8+细胞几乎检测不到IFN-γ、IL-2、IL-4和IL-10.结论 在体外,RATG可以刺激CD4+细胞和CD8+细胞上调多种促进免疫抑制的共刺激分子基因表达,促进其分泌与免疫调节相关的IFN-γ、IL-2、IL-4和IL-10.     

Acute rejection after liver transplantation: Is there a specific immunological pattern?

The aim of the study was to assess various T-cell subsets and cytokine secretion patterns both in liver tissue and in the peripheral blood of 24 liver transplant patients to assess possible specific immunological involvement in early acute rejection episodes after liver transplantation. Particularly, we studied CD4+ CD7+, CD8+ CD38+, and CD4+ CD25+ T cells by flow cytometry, as well as contemporaneously, interleukin (IL)-2 and IL-10 secretion by ELISpot to determine possible Th1-like immune responses and the immunomodulation expressed by Treg cells in acute liver rejection, respectively. As a control group we included patients transplanted without acute rejection. Early acute rejection within the first 4 weeks was proven histologically in 42% of patients. It was associated with a greater expression of CD4+ CD7+ and CD8+ CD38+ T cells in the liver than in the blood (P < .001). A contemporaneous reduced expansion of liver Treg cells was evident in patients with acute rejection (P < .001). Our data suggested that a preferential Th1-like immune mechanism operated in local fashion as characterized by a decreased presence in the liver and blood of Treg cells.     

Immunosuppressive activity of the Chinese medicinal plant Tripterygium wilfordii. III. Suppression of graft-versus-host disease in murine allogeneic bone marrow transplantation by the PG27 extract

BACKGROUND: PG27 is an active fraction purified from an extract of a Chinese medicinal plant, Tripterygium wilfordii Hook f. We tested PG27 in murine allogeneic bone marrow transplantation (BMT) and investigated the mechanism of graft-versus-host disease (GVHD) suppression. METHODS: Recipients in the C57BL/6 --> BDF1 murine BMT model received oral or intraperitoneal PG27. RESULTS: Fourteen days of PG27 given orally or intraperitoneally prevented GVHD development and produced extended disease-free survival (more than 300 days) for many animals. PG490-88, a semisynthetic derivative of PG490 (triptolide, present in PG27), was also efficacious. PG27 reduced day 7 splenic allospecific cytotoxic T lymphocyte levels by more than 99% compared with vehicle-treated mice. Compared with normals, spleens from control allogeneic BMT mice displayed significantly reduced mononuclear cell content, an increased percentage of CD8+ cells, fewer CD4+ cells, and more activated ([interleukin-2 receptor+], IL-2R+) CD8+ T cells. PG27 increased mononuclear cell recovery, and significantly reduced the day-14 percentages of CD3+ and IL-2R+ cells in allogeneic BMT mice, producing results similar to those for syngeneic BMT mice. PG27 significantly increased concanavalin A-stimulated in vitro IL-4 production by day-14 splenocytes, with a 7- to 8-fold higher level than that produced by control cells. CONCLUSIONS: PG27 treatment for only 14 days prevented GVHD induction and development and produced long-term survival. PG27 largely normalized splenic T lymphocyte subsets, reduced allospecific cytotoxic T lymphocyte activity, and increased IL-4 production capability. PG27 may suppress GVHD by the induction of anergy and a deviation away from a proinflammatory phenotype, which could be reflected in the increased potential for IL-4 production.     

High-avidity antitumor T-cell generation by toll receptor 8-primed, myeloid- derived dendritic cells is mediated by IL-12 production

BACKGROUND: High-level production of heterodimeric p70 interleukin (IL)-12 by myeloid-derived dendritic cells (DCs) requires 2 signals: interferon gamma (IFN-gamma) and a maturation signal provided by CD40 ligation (CD40L) or lipopolysaccharide (LPS). METHODS: In the current study we demonstrate that signaling through toll-like receptor (TLR) 8, but not TLR3, TLR2, or TLR4, provides a priming signal to myeloid-derived DC for high IL-12 p70 heterodimer production. RESULTS: All the TLR agonists induced maturation of DC as evidenced by increased expression of CD83, CD80, and CD86. Both IFN-gamma and TLR7/8 agonist R848 increased expression of TLR8 in immature monocyte-derived DCs. The combination of TLR7/8 agonist R848 and maturation signals LPS or CD40L induced high-level expression of IL-12p35 and p40 similar to that induced by IFN-gamma plus LPS. In contrast, receptor agonists specific for TLR7 did not prime for IL-12 production. The p70 IL-12 produced by the TLR8-primed DC polarized CD4+ T for Th1 cytokine production and induced CD8+ T cells, displaying high functional avidity with enhanced tumor cell recognition. CONCLUSIONS: The data suggest that toll 8 receptor agonists are useful for inducing type-1 polarized DCs for vaccine design in treating cancer and infectious disease.     

A central role for CD95 (Fas) in T-cell reactivity after injury

BACKGROUND: Recent findings indicate that severe injury primes the immune system for an enhanced and lethal proinflammatory cytokine response against bacterial-derived superantigens. This study asked whether this response to injury involves the CD95 (Fas) signaling pathway. METHODS: To assess superantigen-mediated mortality, wild-type (WT) C57BL/6 and Fas-deficient C57BL/6 lpr (-/-) (lpr) mice underwent burn or sham injury and were challenged 2 hours later with staphylococcal enterotoxin B (SEB). Spleen cells from sham and burn WT or lpr mice were stimulated in vitro with SEB to assess injury effects on IL-2, TNF-alpha, and IFN-gamma production. RESULTS: Lpr burn mice survived the SEB challenge (100% survival), while WT burn mice showed a high mortality (17% survival, P < 001, analysis of variance [ANOVA]). Sham lpr or WT mice suffered no mortality to the SEB challenge. In vitro studies demonstrated that burn lpr mice produced significantly less TNF-alpha, IFN-gamma, IL-2 than burn WT mice (P <.01, ANOVA). Burn injury markedly enhanced SEB-stimulated IFN-gamma production by WT spleen cells and CD8+ T cells, while this did not occur in SEB-stimulated lpr spleen cells. CONCLUSIONS: These findings support the hypothesis that the CD95 (Fas) signaling pathway plays an integral role in the injury-induced enhanced and lethal T-cell reactivity against bacterial superantigens.