未成熟树突细胞免疫诱导同种移植物存活延长

目的利用未成熟DC免疫受鼠诱导同种移植物存活延长,分析未成熟DC在诱导同种免疫低应答反应中的可能机理。方法以小鼠耳后心肌移植为模型,观察未成熟DC和成熟DC免疫受鼠同种移植心肌的存活情况。同时检测未成熟DC免疫的小鼠脾细胞对同种细胞的CTL活性。结果未成熟DC免疫受鼠的同种移植物存活时间明显延长,平均存活期从9.1±0.73d延长到25.4±4.27d,联合使用阿霉素效果更好,平均存活期为30.5±3.98d;C57BL/6未成熟DC免疫的Balb/c小鼠脾细胞对C57BL/6靶细胞的杀伤(3H-TdR释放率为16.32％)明显低于经成熟DC免疫的受鼠的脾细胞(3H-TdR释放率为39.58％)。结论未成熟DC免疫可诱导同种移植心肌的存活明显延长,可能与受鼠体内的效应T细胞对移植物细胞杀伤低下有关。     

Effective induction of immune tolerance by portal venous infusion with IL-10 gene-modified immature dendritic cells leading to prolongation of allograft survival

Dendritic cells (DC) not only initiate T cell responses, but are also involved in the induction of tolerance. The functional properties of DC are strictly dependent on their state of maturation. It has been shown that immature DC can induce immune tolerance and prolong allograft survival. Interleukin-10 (IL-10) is an important immunosuppressive cytokine which inhibits maturation and function of DC. In order to improve the tolerogenicity of DC, we and others showed that adenovirus vectors can effectively mediate IL-10 genetic modification of DC, and IL-10 genetic modification can inhibit MHC II, B7.2, and CD40 expression, IL-12 secretion and the T cell stimulatory capacity of DC. The primary aim of this study is to examine the in vivo effects of this approach on allograft survival in a murine cardiac allograft transplantation model. To our surprise, we observed that infusion of immature DC genetically modified to express IL-10 (DC-IL-10) via the tail vein could not prolong allograft survival in the recipients, but shortened their survival. More interestingly, portal venous infusion of DC-IL-10 markedly prolonged allograft survival. The diverse effects of DC-IL-10 infusion through different routes may be due to the different immune responses to alloantigens in recipients that received DC-IL-10 via either the portal or the tail vein. Decreased cytotoxicity, polarization of Th2 response, poor T cell stimulating activity of liver DC and enhanced incidence of donor DC in the recipients may contribute to the more efficient prolongation of allograft survival observed after portal venous infusion of DC-IL-10. These results suggest that portal venous infusion may be an effective approach for immature DC to induce immune tolerance or hyporesponsiveness against donor antigens, and prolong allograft survival.Abbreviations APC Antigen-presenting cells - CTL Cytotoxic T lymphocytes - DC Dendritic cells - DC-IL-10 IL-10 gene-modified immature dendritic cells - iDC Immature dendritic cells - IL-10 Interleukin-10 - MLR Mixed leukocyte reaction - MOI Multiplicity of infection     

Mechanisms of prolongation of allograft survival by HLA-G/ILT4-modified dendritic cells

Engagement of inhibitory receptors on dendritic cells (DCs) is a powerful way to modulate their functions to achieve hyporesponsiveness or tolerance induction. Transgenic mice expressing human ILT4 receptor exclusively on DCs and triggered by HLA-G1 developed long-term survival of allogeneic skin transplant. Here we identify the cellular and molecular mechanisms responsible for that induction of hyporesponsiveness to alloantigen in vivo. Engagement of ILT4 receptor by HLA-G1 resulted in down-regulation of expression of MHC class II and costimulatory molecules, and modulation of cytokine production on DCs. HLA-G-modified DCs from ILT4 transgenic mice promote long-term survival of allografts by mechanisms involving both the induction of regulatory T cells and T-cell anergy. A novel feature of our research was to establish a model for the study of the prospective mechanisms of regulation of alloimmune responses by inhibitory receptors in vivo and analysis of the potential of HLA-G and its inhibitory receptors in modulation of DCs and T-cell function.     

负向调节树突状细胞对心脏移植大鼠调节性T细胞的影响

目的:探讨受者树突状细胞(DC)与体外光化学法(PUVA)处理的供者脾淋巴细胞共培养,对心脏移植受者CD4+CD25+调节性T细胞(Treg)及移植心存活时间的影响。方法:以DA大鼠为供者,Lewis大鼠为受者,SD大鼠为无关供者,建立大鼠腹部异位心脏移植模型。分离正常的供者脾淋巴细胞(SP),制备经PUVA处理的供者脾淋巴细胞(PU-VA-SP)。在体外将DA大鼠PUVA-SP或SP与受者骨髓来源的DC共同培养,收集经上述处理后受者DC,流式细胞术(FCM)检测其表面分子CD80、CD86以及OX6的表达状况。根据受者术前静脉输注的成分将实验动物随机分为3组:①Control组:单纯输注PBS,n=7;②SPDC组:输注加载供者SP的受者大鼠DC,n=8;③PUVA-SPDC组:输注加载PUVA处理的供者SP的受者大鼠DC,n=8。移植术前7d,经外周静脉给受者输注与PUVA-SP共培养后的DC(PUVA-SPDC组)、正常受者DC(DC组)或只输注PBS(Control组),移植术后观察受者移植物的存活时间,检测受者外周血中CD4+CD25+T细胞、CD4+CD25highT细胞的比例及其Foxp3表达状况。过继转移PUVA-SPDC组受者大鼠的T细胞后,检测正常LEW大鼠对供者抗原或无关抗原的DTH反应。结果:受者DC与供者未经处理的脾淋巴细胞(SP)混合培养后,其表面分子CD80、CD86以及OX6的表达分别为16.6%±0.72%、36.5%±0.87%及65.6%±1.45%,明显高于未处理DC组(3.53%±0.27%、13.0%±0.57%及27.7%±1.23%)(P0.01);而受者DC与PUVA处理过的供者脾淋巴细胞(PUVA-SP)混合培养后,其表面分子的表达仍保持较低的水平,CD80、CD86以及OX6的表达分别为3.9%±0.12%、13.4%±0.59%及28.0%±1.73%,与未经任何处理的受者DC无统计学差异(P0.05)。移植术后,PUVA-SPDC组受者,外周血CD4+CD25+T、CD4+CD25highT细胞占CD4+T的比例分别是18.97%和3.81%,明显高于输注DC组(4.40%和0.81%)和Control组(3.11%和0.09%)的大鼠(P0.01)。PUVA-SPDC组大鼠外周血CD4+CD25+T细胞中Foxp3表达率为29%±1.73%,CD4+CD25highT细胞中Foxp3阳性率高达95%±1.67%,均明显高于对照组(12%±0.58%和19.3%±2.03%)及DC(16.3%±0.88%和52.0%±1.73%)组(P0.01)。PUVA-SPDC组大鼠移植心存活时间为(27.3±0.98)d,与Control组(6.7±0.29)d及DC组(11.0±0.32)d相比,明显延长(P0.01)。过继转移实验显示,接受PUVA-SPDC组受者T细胞的正常LEW大鼠对DA大鼠抗原的刺激呈特异性免疫低应答状态。结论:PUVA-SPDC能够在移植受者体内诱生CD4+CD25+Foxp3+Treg,同时诱导抗原特异性免疫低反应,进而延长异基因移植物的存活时间。     

未成熟树突状细胞诱导建立异基因嵌合体及延长移植物存活的可能机制

目的：研究应用供体来源的未成熟树突状细胞(inDCs)注射受体小鼠后，诱导形成异基因嵌合体及延长移植物存活的机制。方法：(1)应用供体(C57BL／6)来源的骨髓细胞，在体外培养出imDCs，灭活后体内输注或体外直接刺激受体小鼠(Balb/C)的脾细胞，观察脾细胞对供体细胞的应答反应；(2)取已建立异基因嵌合体并有效延长移植物存活的受体小鼠的脾细胞，观察其对供体细胞刺激的应答反应；(3)通过半定量RT—PCR检测不同免疫状态下Th1／Th2型细胞因子的表达情况。结果：应用imDCs体外预刺激脾细胞或体内注射imDCs受鼠的脾细胞，均呈现对供鼠脾细胞刺激的特异性低应答，这种低应答主要出现在受鼠脾细胞在供鼠脾细胞刺激后的72小时内；建立异基因嵌合体并延长移植物存活的受鼠对来自供鼠脾细胞的刺激也表现为低应答，而对于无关第三者脾细胞的刺激仍保持较高水平，二者比较，统计学处理有显著性差异(P＜0．05)；在诱导形成异基因嵌合体及延长移植物存活的过程中，一定程度上显示出Th1／Th2模式的偏移。结论：应用供体来源的imDCs注射给受体，诱导形成异基因嵌合体和延长移植物存活的机制可能与imDCs诱导受体T细胞无能有关，而且此过程中在一定程度上表现为Th1向Th2方向的免疫偏移。     

Lymphocyte changes associated with prolongation of cardiac allograft survival in adult mice using anti-CD4 monoclonal antibody.

This study investigated the effect of anti-CD4 MoAb treatment on lymphocyte phenotype and function and correlated these changes with the prolongation of cardiac allograft survival in adult mice. Indefinite survival of heterotopic cardiac allografts was obtained in several fully allogeneic strain combinations when two doses of the anti-CD4 MoAb, YTS 191.1, were given at the time of transplantation. A dose response analysis in the C57BL/10 to C3H/He strain combination showed that very low doses of YTS 191.1 (25 micrograms/dose) were able to induce prolonged allograft survival when administered perioperatively. At the time of transplantation the immunosuppression induced by administration of the anti-CD4 MoAb is not antigen-specific, as heart grafts from different donor strains, mismatched for both major and minor histocompatibility antigens, showed prolonged survival in treated recipients. Immunocompetence was restored by 6 weeks after MoAb treatment, as recipients regained the ability to reject a cardiac allograft transplanted at this time point. However, while recovery of immunocompetence could be demonstrated in vivo, leucocytes isolated from the peripheral lymphoid organs of treated mice continued to be hyporesponsive in mixed leucocyte culture (MLC). Phenotypic analysis of the peripheral lymphoid tissues showed that C3H/He recipients treated with 25 micrograms/dose of YTS 191.1 had a marked, but not complete, elimination of the CD4+ subset at the time of transplantation, which was gradually restored to 50% of normal by 6 weeks after treatment. Thus, complete elimination of the CD4+ subset was not required to achieve indefinite allograft survival, and immunocompetence, as assessed in vivo, returned even when the CD4+ subset was present at half the normal level. Low doses of anti-CD4 MoAb (25 micrograms) had no effect on the expression of the CD4 molecule by thymocytes, and yet thymocytes were hyporesponsive to alloantigen in vitro. At higher doses of YTS 191.1, immature CD4+8+ thymocytes were selectively depleted. These results suggest that anti-CD4 MoAb therapy may modulate the intrathymic T cell selection process. These studies provide further insight into the mechanism of action of low dose, depleting anti-CD4 MoAb therapy in allograft rejection, and form a basis from which rational modifications to therapeutic protocols in transplantation models can be made.     

α-黑素细胞刺激素基因修饰的树突状细胞延长小鼠移植心脏的存活时间

为观察α-黑素细胞刺激素(α-MSH)基因修饰的树突状细胞(DC)抑制同种异型基因小鼠心脏移植排斥反应的效果,以腺相关病毒(AAV)为载体将α-MSH基因导入BALB/c小鼠骨髓来源的未成熟DC,制备了α-MSH基因修饰的DC(α-MSH-DC)。在小鼠心脏移植前7 d,将α-MSH-DC输至受者C57BL/6小鼠体内,通过免疫组化方法观察供者α-MSH-DC在受者脾脏内存在的情况,用混合淋巴细胞反应(MLR)测定受者脾脏T细胞对供者同种抗原的反应性。通过颈部Cuff法小鼠异位心脏移植模型,观察心脏移植物存活时间,并用ELISA方法测定受者血清细胞因子水平的变化。结果显示,α-MSH-DC在受者脾脏内存在时间延长,能诱导受者脾脏T细胞的抗原特异性低反应性,使移植心脏存活天数延长至(19.3±2.35)d,较PBS对照组的(7.0±0.33)d明显延长(P<0.01)。使受者小鼠血清IL-2和IFNγ-水平显著降低(P<0.01),明显升高IL-4、IL-10水平(P<0.01)。表明移植前输入供者α-MSH基因修饰的DC能延长同种异型基因心脏移植的存活时间。     

Beneficial effect of amrinone on murine cardiac allograft survival.

Amrinone is a non-glycoside positive inotropic agent with an inhibitory effect on a cyclic adenosine monophosphate (AMP) phosphodiesterase isoenzyme. In the present study, we examined the immunosuppressive action of amrinone, since several other cyclic AMP-elevating agents have been shown to suppress T lymphocyte activation. First, the in vivo effects of amrinone were investigated. Oral amrinone treatment, at 40 mg/kg per day, significantly prolonged median cardiac allograft survival compared with non-treated controls (22.0 days versus 10.5 days, P < 0.01) when DBA/2 mouse hearts (H-2d) were heterotopically transplanted into C57B1/6 mice (H-2b). Histopathological examination showed that there was less prominent cellular infiltration in the amrinone-treated than in the non-treated allografts. Plasma amrinone concentrations of mice after a single oral dose of 40 mg/kg were within the range of clinical relevance. To clarify the mechanism of action, in vitro studies were done. The generation of specific cytotoxic T lymphocytes after mixed lymphocyte culture was significantly suppressed by addition of amrinone to the culture medium at 5 micrograms/ml. The production of IL-2 and the interferon-gamma during mixed lymphocyte culture was also suppressed by amrinone at 5 micrograms/ml. However, the level of intracellular cyclic AMP in mouse splenic lymphocytes was not affected significantly by the same dose of amrinone. In conclusion, amrinone has immunosuppressive actions at the therapeutic doses, and it may be a beneficial agent for therapy against acute cardiac allograft rejection.     

负载滋养层细胞抗原对小鼠树突状细胞表型及功能的影响

目的 研究负载滋养层细胞抗原对小鼠髓源性树突状细胞(DC)分化成熟过程的影响,获得致耐受性DC.方法 体外使用粒细胞巨细胞集落刺激因子(GM-CSF)诱导小鼠骨髓细胞定向分化、经LPS刺激获得成熟DC;通过外胎盘锥组织块培养法获得滋养层细胞,制备可溶性抗原,加入DC培养体系.流式细胞术检测DC表面共刺激分子及MHC-Ⅱ的表达,ELISA法检测DC分泌IL-10和IL-12的浓度,混合淋巴细胞培养评估 DC刺激同种T细胞增殖、活化的功能.结果 成熟DC表型为CD40high CD80highCD86highMHC-Ⅱhigh,分泌大量的IL-12和极少量的IL-10 ,体外能有效刺激T细胞的增殖;负载滋养层细胞抗原的DC表型为CD40midCD80lo wCD86lowMHC-Ⅱlow,在分泌大量IL-12的同时IL-10也明显升高,不能有效刺激T细胞增殖,并使T细胞分泌细胞因子呈现明显Th2偏倚.结论 负载滋养层细胞抗原后的DC表面共刺激分子及MHC-Ⅱ表达降低,刺激T细胞增殖能力下降;其自分泌和促使T细胞旁分泌的细胞因子呈现Th2偏倚,是一种耐受性DC.     

Distinctive role of donor strain immature dendritic cells in the creation of allograft tolerance

Dendritic cells (DCs) are pivotal antigen-presenting cells and serve a unique role in initiating immunity. To test the hypothesis that pre-immunization of recipient with certain DC subsets of donor origin can influence graft outcome, we have studied the effects of immunization with allogeneic CD4(+)CD8(-)CD11c(+) dendritic cell (CD4(+)DC) and CD4(-)CD8(+)CD11c(+) dendritic cell (CD8(+)DC) on the allograft response. Although both immature CD4(+)DC and CD8(+)DC subsets from DBA/2 were able to prime naive allogeneic C57BL/6 (B6) T cells in mixed lymphocyte reaction (MLR), CD8(+)DC exerted more vigorous alloimmune responses than CD4(+)DC did. Also, CD4(+)DC-driven allogeneic T cell response was attenuated more significantly by anti-CD154 mAb than CD8(+)DC-driven response. Consistent with the MLR results, combined pre-treatment with CD4(+)DC, but not CD8(+)DC, plus anti-CD154 mAb produced donor strain-specific long-term graft survival and induced tolerance while treatment with CD8(+)DC plus anti-CD154 mAb created minimal prolongation of allograft survival in a pancreas islet transplant model (DBA/2-->B6). The beneficial effects exerted by CD4(+)DC and anti-CD154 mAb pre-treatment were correlated with T(h)1 to T(h)2 immune deviation and with the amplified donor-specific suppressive capacity by recipient CD4(+)CD25(+) T cells. These findings highlight the capacity of CD4(+)DC to modulate alloimmune responses, and suggest therapeutic approaches for the induction of donor-specific tolerance.     

小鼠骨髓成熟与不成熟树突状细胞中RelB基因的表达

目的:探讨体外分离培养的小鼠骨髓来源的成熟与未成熟DC中核转录因子RelB(avianreticuloendotheliosisviral(v-rel)oncogenerelatedB)基因的表达。方法:无菌从C57BL/6小鼠股骨和胫骨中取出骨髓细胞,利用rmGM-CSF和rmIL-4联合诱导骨髓前体细胞产生未成熟的DC,未成熟的DC在培养结束前18h经LPS刺激获得成熟的DC,用流式细胞术分析它们的表型,用RT-PCR和免疫荧光染色法检测成熟与未成熟DC中,RelBmRNA和其蛋白的表达。结果:流式细胞术分析显示未成熟的DC中MHC-Ⅱ类分子和共刺激分子(CD86和CD40)呈低水平表达;而成熟的DC则呈高水平表达。RT-PCR和免疫荧光染色法检测结果均显示,RelB基因在未成熟的DC中呈低水平表达;而在成熟的DC中呈高水平表达,两者比较具有统计学意义(P<0.01)。结论:RelB基因的表达与小鼠骨髓来源的DC的成熟状态密切相关。抑制DC中RelB基因的表达,有可能诱导产生具有耐受原性的未成熟的DC。     

术前输注供者CD80~(low)/CD86~(low)树突状细胞,延长小鼠同种异体移植心脏存活

目的 :应用B7- 1和B7- 2反义寡核苷酸 (ASB7- 1/ASB7- 2oligo)抑制CD80 (B7- 1)、CD86 (B7- 2 )在供体小鼠骨髓树突状细胞 (DC)上的表达 ,观察这类DC对同种异体小鼠心脏移植存活时间的影响并探讨其机理。方法 :小鼠B7- 1和B7- 2反义寡核苷酸在lipofectamine协助下分别转染供体鼠C5 7BL/10J(B10 )小鼠骨髓DC ,流式细胞仪检测其CD80 /CD86的表达 ,证实为CD80 low/CD86 low。将各组DC经尾静脉输注到受体小鼠C3H/HeJ(C3H)体内 ,1周后进行心脏移植术 ,观察存活时间 ;体外实验观察各组DC对同种异体T细胞的激活作用 ,包括混合淋巴细胞反应、细胞毒性效应、及IL - 2的产生。结果 :ASB7- 1和ASB7- 2分别显著抑制DC表达CD80 /CD86 ;转输这些CD80 low/CD86 lowDC可使小鼠心脏移植物存活时间显著延长 ,分别为 (18.6± 0 .89)d和 (2 3.6 7± 10 .73)d ,与转输成熟骨髓DC(IL - 4DC)组和生理盐水注射组(6 .2 2± 0 .97)d、(11.17± 1.72 )d比较 ,均有显著差异 (P <0 0 1) ;CD80 low或CD86 lowDC对异体T细胞激活作用较弱 ,表现为T细胞增殖能力、IL - 2产生及细胞毒杀伤均明显低。结论 :应用反义寡聚核苷酸转染供者DC ,降低其CD80或CD86的表达 ,可以抑制供者特异性的免疫应答 ,延长移植物存活时间。     

术前输注供者CD80low/CD86low树突状细胞，延长小鼠同种异体移植心脏存活

目的:应用B7-1和B7-2反义寡核苷酸(ASB7-1/ASB7-2oligo)抑制CD80(B7-1)、CD86(B7-2)在供体小鼠骨髓树突状细胞(DC)上的表达,观察这类DC对同种异体小鼠心脏移植存活时间的影响并探讨其机理。方法:小鼠B7-1和B7-2反义寡核苷酸在lipofectamine协助下分别转染供体鼠C57BL/10J(B10)小鼠骨髓DC,流式细胞仪检测其CD80/CD86的表达,证实为CD80^low/CD86^low。将各组DC经尾静脉输注到受体小鼠C3H/HeJ(C3H)体内,1周后进行心脏移植术,观察存活时间;体外实验观察各组DC对同种异体T细胞的激活作用,包括混合淋巴细胞反应、细胞毒性效应、及IL-2的产生。结果:ASB7-1和ASB7-2分别显著抑制DC表达CD80/CD86;转输这些CD80^low/CD86^lowDC可使小鼠心脏移植物存活时间显著延长,分别为(18.6±0.89)d和(23.67±10.73)d,与转输成熟骨髓DC(IL-4DC)组和生理盐水注射组(6.22±0.97)d、(11.17±1.72)d比较,均有显著差异(P<0.01);CD80^low或CD86^lowDC对异体T细胞激活作用较弱,表现为T细胞增殖能力、IL-2产生及细胞毒杀伤均明显低。结论:应用反义寡聚核苷酸转染供者DC,降低其CD80或CD86的表达,可以抑制供者特异性的免疫应答,延长移植物存活时间。     

Co-culture of apoptotic breast cancer cells with immature dendritic cells: a novel approach for DC-based vaccination in breast cancer

A dendritic cell (DC)-based vaccine strategy could reduce the risk of recurrence and improve the survival of breast cancer patients. However, while therapy-induced apoptosis of hepatocellular and colorectal carcinoma cells can enhance maturation and antigen presentation of DCs, whether this effect occurs in breast cancer is currently unknown. In the present study, we investigated the effect of doxorubicin (ADM)-induced apoptotic MCF-7 breast cancer cells on the activation of DCs. ADM-induced apoptotic MCF-7 cells could effectively induce immature DC (iDC) maturation. The mean fluorescence intensity (MFI) of DC maturity marker CD83 was 23.3 in the ADM-induced apoptotic MCF-7 cell group compared with 8.5 in the MCF-7 cell group. The MFI of DC co-stimulatory marker CD86 and HLA-DR were also increased after iDCs were treated with ADM-induced apoptotic MCF-7 cells. Furthermore, the proliferating autologous T-lymphocytes increased from 14.2 to 40.3% after incubated with DCs induced by apoptotic MCF-7 cells. The secretion of interferon-γ by these T-lymphocytes was also increased. In addition, cell-cell interaction between apoptotic MCF-7 cells and iDCs, but not soluble factors released by apoptotic MCF-7 cells, was crucial for the maturation of iDCs. These findings constitute a novel in vitro DC-based vaccine strategy for the treatment of breast cancer by ADM-induced apoptotic MCF-7 cells.     

Expression of milk fat globule epidermal growth factor 8 in immature dendritic cells for engulfment of apoptotic cells

Milk fat globule epidermal growth factor 8 (MFG-E8) is a protein that stimulates the engulfment of apoptotic cells by phagocytes. Here, we show that mouse immature dendritic cells (DC) generated in vitro by culturing bone marrow progenitors in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF), and Langerhans cells present in the skins, expressed MFG-E8. Bone marrow-derived macrophages generated by M-CSF did not express MFG-E8. MFG-E8 expressed in immature DC was found to be secreted as exosomes. The expression of MFG-E8 was significantly suppressed when the immature DC were induced to mature by treating them with lipopolysaccharides. This expression of MFG-E8 was well correlated with the ability of the cells to engulf apoptotic cells. That is,immature DC phagocytosed apoptotic cells more efficiently than did mature DC or bone marrow-derived macrophages. The ability of immature DC to engulf apoptotic cells was severely reduced when the immature DC were prepared from MFG-E8-deficient mice. These results indicated that MFG-E8 plays an essential role in the engulfment of apoptotic cells by bone marrow-derived immature DC.     

Synthetic and biological polycations in prolongation of skin allograft survival time

Summary The degree of immuno-auppressive activity of the lysine-rich F₁-fraction and the arginine-rich F₃-fraction of histone extracted from calf thymus nuclei was compared with that of total histone and of synthetic polycations using transplantation immunity as experimental model. Under comparable conditions total histone and the F₁-fraction were likewise active in prolongation of allograft survival time, whereas the F₃-fraction was significantly less active. Poly-l-lysine induced also an inhibition of graft rejection, but its activity was less pronounced compared with the F₁-fraction. Poly-l-arginine showed no activity at all.In addition, the immuno-suppressive effect of total histone extracted from different inbred lines of mice was tested comparatively. Apart from a general activity, it was found in each of four series with different graft-receptor-relationships that an optimal prolongation of skin allograft survival time was uniformly observed, when graft recipients were pretreated with histone from the line of the graft donor or from an unrelated inbred line of the same species. In contrast, in each case pretreatment of graft recipients with histone derived from the line of the recipient was markedly less effective.

---

Zusammenfassung Am Modell der Haut-Homotransplantation wurde der immunosuppressive Effekt der lysinreichen F₁- und der argininreichen F₃-Fraktion von Histon aus Zellkernen von Kalbsthymus mit dem von Gesamthiston und von synthetischen Polycationen verglichen. Unter vergleichbaren Bedingungen bewirkte Gesamthiston und die F₁-Fraktion eine ähnliche Verlängerung der Haftung von Haut-Homotransplantaten. Dagegen war die F₃-Fraktion signifikant weniger wirksam. Auch Poly-l-Lysin bewirkte eine Hemmung der Transplantat-Abstoßung, doch war dieser Effekt weniger ausgeprägt als der von F₁-Histon. Poly-l-Arginin war unwirksam.Außerdem wurde Gesamthiston, das von verschiedenen Inzuchtlinien von Mäusen gewonnen wurde, im Hinblick auf eine Hemmung der Transplantat-Abstoßung verglichen. Von einer allgemeinen Histon-Wirkung abgesehen, hatte in 4 Versuchsserien mit verschiedenen Spender-Empfänger-Kombinationen jeweils das Histon der Linie des Transplantat-Spenders oder das einer dritten Inzuchtlinie von Mäusen den besten Effekt. Dagegen war in jedem Fall das Histon des Transplantat-Empfängers nennenswert weniger wirksam.

---

---

Supported by Grant Gi 27/9 of the Deutsche Forschungsgemeinschaft.

---

The technical assistance of Miss M. Müllenmeister and of Miss Ch. Möller is gratefully acknowledged.     

Function of indoleamine 2,3-dioxygenase in corneal allograft rejection and prolongation of allograft survival by over-expression

Indoleamine 2,3-dioxygenase (IDO) suppresses T cell responses by its action in catabolising tryptophan. It is important in maintenance of immune privilege in the placenta. We investigated the activity of IDO in the cornea, following corneal transplantation and the effect of IDO over-expression in donor corneal endothelium on the survival of corneal allografts. IDO expression was analysed and functional activity was quantified in normal murine cornea and in corneas following transplantation as allografts. Low levels of IDO, at both mRNA and protein levels, was detected in the normal cornea, up-regulated by IFN-gamma and TNF. Expression of IDO in cornea was significantly increased following corneal transplantation. However, inhibition of IDO activity in vivo had no effect on graft survival. Following IDO cDNA transfer, murine corneal endothelial cells expressed functional IDO, which was effective at inhibiting allogeneic T cell proliferation. Over-expression of IDO in donor corneal allografts resulted in prolonged graft survival. While, on one hand, our data indicate that IDO may augment corneal immune privilege, up-regulated IDO activity following cytokine stimulation may serve to inhibit inflammatory cellular responses. While increasing IDO mRNA expression was found in allogeneic corneas at rejection, over-expression in donor cornea was found to significantly extend survival of allografts.     

早期和晚期凋亡细胞对骨髓源性不成熟DC影响的实验研究

目的 研究早期、晚期凋亡细胞对骨髓源性不成熟DC（imDC）的影响。方法 体外以紫外线照射诱导出早期凋亡细胞；将照射后的细胞在37℃，5％CO2条件下孵育10h，得到晚期凋亡细胞；在-70℃条件下反复冻融得到坏死细胞碎片。提取、纯化并培养骨髓源性imDC；分别以流式细胞仪、ELISA、^3H-TdR掺入的混合淋巴细胞反应等方法分析imDC吞噬早期、晚期凋亡细胞或坏死细胞碎片后在表达共刺激分子、分泌IL-12 p70以及刺激T淋巴细胞增殖等方面的差异。结果 imDC吞噬晚期凋亡或坏死细胞碎片后，明显趋于成熟，表现为MHCⅡ、CD40、CD80、CD86的表达均显著上调，分泌IL-12 p70增强，和T淋巴细胞混合培养后可以充分激活T淋巴细胞。而吞噬早期凋亡细胞后，仍然维持不成熟状态，表现为MHCⅡ、CD40、CD80、CD86的表达均维持于低水平，和培养中的imDC相比差异无统计学意义；分泌IL-12 p70的水平以及刺激T淋巴细胞增殖的能力均显著低于吞噬坏死细胞或晚期凋亡细胞后的DC，和培养中的imDC相比差异无统计学意义。结论 早期凋亡细胞和晚期凋亡细胞的性质完全不同，晚期凋亡细胞可以充分活化抗原提呈细胞，并进一步激活T淋巴细胞，而早期凋亡细胞没有这种活化作用。     

Histoincompatibility-associated differences in the phenotypes of murine cardiac allograft infiltrating T cells.

Mechanisms of graft rejection may be governed in part by the kind and degree of histocompatibility differences between donor and recipient. Cardiac allograft rejection was studied in three murine models selected to provide disparity at different major histocompatibility complex (MHC), minor lymphocyte stimulating (Mls) and other minor histocompatibility loci. Graft survival for the A.TL to A.TH combination (M3) was significantly longer (median day of rejection 15.0 days) than both the B10.A to AKR (M2) or the C57BL/6 to C3H/HeN (M1) donor-recipient combinations (median days of rejection: 9.0 days and 9.0 days respectively; P < 0.001). The infiltration of grafts by T cells was examined by removal of grafts serially post-transplantation and culturing mechanically disrupted graft tissue with interleukin-2 (IL-2). Recovery of T cells by this method revealed highly reproducible characteristics (kinetic and phenotypic), unique to each donor-recipient combination. Cultures from M1 and M2 grafts had differing CD4/CD8 T-cell ratios at days 2 (1.8 versus 0.7, respectively) and 4 (1.6 versus 0.1, respectively) post-transplantation. The M3 model differed from M2 (at days 4, 8 and 10) and from M1 (at days 8 and 10). At these times, cultures of M3 grafts contained a significantly increased percentage of CD4 cells and significantly decreased percentage of CD8 cells (CD4/CD8 ratios 0.9-1.3) by comparison with M1 (CD4/CD8 ratios 0.02-0.04) and M2 (CD4/CD8 ratios 0.1-0.02). Long-surviving M3 grafts (greater than 30 days post-transplantation) were compared with grafts removed immediately upon cessation of graft function (days 14, 15 and 18 post-transplantation). There was a significant difference between these groups in the ratios of CD4/CD8 T-cell ratios (1.1 versus 0.4, respectively). This study suggests that the cellular rejection mechanism of a graft is a variable process driven by the individual histocompatibility antigen disparity between donor and recipient. These findings may have diagnostic and therapeutic applications in organ transplantation.