Activated circulating dendritic cells after hematopoietic stem cell transplantation predict acute graft-versus-host disease

BACKGROUND: Dendritic cells (DC) are central to the development of acute graft-versus-host disease (GVHD) following allogeneic hematopoietic stem cell transplantation (alloHSCT). We hypothesized that DC activation status determines the severity of GVHD and that activated DC may be detected in the circulation prior to clinical presentation of GVHD. METHODS: Following transplant, blood samples were obtained twice weekly from alloHSCT patients. Myeloid (CD11c+) and plasmacytoid (CD123hi) DC were enumerated by flow cytometry, and activated myeloid DC were identified using the CMRF-44 monoclonal antibody. RESULTS: Of 40 alloHSCT patients, 26 developed acute GVHD. Severity of GVHD was associated with low total blood DC counts (P=0.007) and with low myeloid and plasmacytoid DC numbers (P=0.015 and 0.003). The CMRF-44 antigen was expressed on blood CD11c+ DC in all cases prior to GVHD onset, whereas of the 14 patients without GVHD, seven had no CMRF-44+ CD11c DC. Patients with CMRF-44+ CD11c+ DC in more than 20% of samples were more likely to subsequently develop acute GVHD (P=0.001, odds ratio=37.1), while patients who developed grade 2-4 GVHD had prior higher percentages of CMRF-44+ CD11c+ DC compared to grade 0-1 GVHD patients (P=0.001). CMRF-44 expression on >7.9% CD11c+ DC predicted for subsequent development of GVHD with a sensitivity of 87.5% and specificity of 79.2%. CONCLUSIONS: Activation status, as assessed by CMRF-44 antigen expression, of blood CD11c+ DC is highly associated with acute GVHD and these cells may be targets for therapeutic intervention.     

In vitro depletion of tissue-derived dendritic cells by CMRF-44 antibody and alemtuzumab: implications for the control of Graft-versus-host disease

Graft-versus-host disease (GvHD), a life-threatening complication of bone marrow transplantation, is initiated by donor T cells reacting to recipient dendritic cells (DC). GvHD can be controlled by attenuating donor T cells, but few strategies exist to target DC, particularly resident tissue DC, despite recent evidence of their importance. In this report, CMRF-44, a mouse monoclonal IgM reactive to human DC, is tested against human Langerhans cells (LC) in vitro. CMRF-44 antigen is expressed at low level on fresh LC but is up-regulated 40-60-fold during migration. CMRF-44 and complement kill more than 97% of migratory LC in vitro and inhibit allostimulation by LC up to 95%. In comparison, alemtuzumab, which binds CD52, reacts weakly with primary LC and fails to induce significant lysis with complement (less than 5%). These results highlight the potential of new therapeutic antibodies active against tissue DC to control graft-versus-host reactions.     

PHENOTYPIC CHARACTERISATION OF THE DENDRITIC CELL INFILTRATE IN PROSTATE CANCER

Purpose

To investigate whether dendritic cells (DC), which as professional antigen presenting cells have the capacity to stimulate immune responses against tumour associated antigens, are recruited into and activated within prostate cancer.

Materials and Methods

Immunoenzyme and immunofluorescence labelling was used to identify leucocyte and DC subsets within 15 cases of prostate cancer. Cell numbers were compared with numbers in adjacent normal prostatic tissue. Total DC numbers were identified as CD45⁺ leucocytes not coexpressing any lineage specific markers. The Langerhans cell (LC) subset was detected using anti CD1a staining and activated DC were identified by their expression of either CD83, CD86 or CMRF44.

Results

DC were found to represent a small subset of leucocytes present in both benign and malignant prostatic tissue. Statistically there were significantly less DC and LC in prostate cancer compared with normal prostatic tissue. While only a small subset of DC expressed markers of activation in prostate cancer, this was significantly more than the virtual absence of activated DC in normal prostatic tissue.

Conclusions

This is the first time that DC have been studied in prostate cancer using the relatively new DC specific monoclonal antibodies CD83 and CMRF-44. These findings suggest that there is no active recruitment of DC into prostate cancer and those DC present are only minimally activated.     

In vitro study of expression of interleukin-2 receptors in T-lymphocytes from patients with IgA nephropathy

The present study was undertaken to examine the expression of interleukin-2 receptor (IL-2R)/CD25 antigen in cultured T-lymphocyte subsets in IgA nephropathy. Twenty-four IgA nephritic patients, 12 patients with chronic glomerulonephritis (non-IgA nephropathy), and 17 healthy controls were studied in an infection-free interval. T-cell subsets in peripheral blood mononuclear cells (PBMC) and activated T-lymphocyte subsets expressing IL-2R were determined by double immunofluorescence staining with fluorochromes conjugated to monoclonal antibodies against T-helper/inducer (CD4+) cell, T-suppressor/cytotoxic (CD8+) cell, B (CD20+) lymphocytes, and IL-2R. The percentages of CD4+ and CD8+ lymphocytes, CD4/CD8 ratio, and total activated lymphocytes (with IL-2R/CD25 antigen) did not differ between the IgA nephritic patients, patients with chronic glomerulonephritis, and healthy controls in freshly isolated, unstimulated lymphocytes or PBMC cultured with pokeweed mitogen. Following pokeweed mitogen stimulation for 5 days, 17.3 +/- 10.3%, 16.6 +/- 8.4%, and 16.7 +/- 9.4% of PBMC from IgA nephritic patients, patients with chronic glomerulonephritis, and controls respectively expressed IL-2R (p greater than 0.05). However, the individual T-cell subsets bearing IL-2R were distinctly different between the IgA nephritic patients and patients with chronic glomerulonephritis or healthy controls. IgA nephritic patients had increased activated CD4+ lymphocytes (with IL-2R) (p less than 0.025) and reduced activated CD8+ lymphocytes (p less than 0.025). Our study suggests a defective immunoregulation in IgA nephropathy with enhanced T-helper/inducer and reduced T-suppressor/cytotoxic activity when stimulated with mitogen and probably, during clinical exacerbation.     

Long-term culture of islets abrogates cytokine-induced or lymphocyte-induced increase of antigen expression on beta cells

BACKGROUND: Immunogenicity of a graft depends on its expression of major histocompatability complex (MHC) antigens and adhesion molecules and on the amount of intragraft leukocytes, the so-called passenger leukocytes. Although long-term culture reduces passenger leukocytes, permanent acceptance is not necessarily observed after allogeneic transplantation. Because little is known about antigen expression on the surface of islet cells after long-term culture of islets, we investigated whether antigen expression of pancreatic beta cells is influenced by long-term culture and whether long-term culture can counteract the increase of antigen expression induced by cytokines or by allogeneic lymphocytes. We also investigated whether long-term cultured islets were able to stimulate allogeneic lymphocytes to produce cytokines. METHODS: Isolated LEW.1A (RT1a) rat islets of Langerhans were cultured for 14 and 28 days. Precultured and freshly-isolated islets were then incubated for 2 days with rat recombinant interferon (rIFN)-gamma (1,000 IU/mL), or were co-cultured for 4 days with LEW.1W (RT1u) splenic lymphocytes. RESULTS: Long-term culture significantly reduced CD45 leukocytes within the islets and decreased the amount of beta cells expressing intercellular adhesion molecule (ICAM)-1, whereas MHC antigen expression remained unchanged. After incubation of freshly isolated islets with IFN-gamma induction of MHC class II antigens on beta cells, an increase of MHC class I antigen density and an enhancement of ICAM-1+ beta cells were observed. Similar results were found after co-culturing with allogeneic lymphocytes. Using precultured islets, the induction of MHC class II on beta cells by IFN-gamma was still present but significantly lower and was absent after co-culture with allogeneic lymphocytes. Enhancement of ICAM-1+ beta cells by IFN-gamma or by allogeneic lymphocytes was markedly lowered because of preculturing. The proportion of MHC class I beta cells remained unchanged; however, antigen density of long-term cultured islets (28 days) could not be enhanced by allogeneic lymphocytes. Precultured islets were not able to stimulate allogeneic lymphocytes to produce and release normal amounts of cytokines (IFN-gamma or interleukin [IL]-2). CONCLUSIONS: In conclusion, in addition to reduction-depletion of passenger leukocytes, long-term culturing of islets also is able to counteract the IFN-gamma-induced or allogeneic lymphocyte-induced increase of antigen expression. Therefore, initiation of rejection and generation of cytotoxic cells might be altered or timely delayed when long-term cultured islets are transplanted. The variable and conflicting in vivo results after transplantation of long-term cultured islets might be explained by the possible indirect antigen presentation, which is not influenced by islet preculture.     

Apoptosis and allograft rejection in the absence of CD8+ T cells.

BACKGROUND: The requirement for cytotoxic T lymphocytes during allograft rejection is controversial. We previously demonstrated that CD8+ T cells are not necessary for allograft rejection or for the induction of apoptosis in rat small intestinal transplantation. In this study, we examined the mechanisms of apoptosis and rejection after liver transplantation in the absence of CD8+ T cells. METHODS: Either Lewis or dark agouti rat liver grafts were transplanted into Lewis recipients to create syngeneic and allogeneic combinations. CD8+ T cells were depleted in an additional allogeneic group by treatment with OX-8 mAb on day -1 and day 1 after liver transplant. RESULTS: Apoptosis and rejection were observed in both the CD8+ T cell-depleted allogeneic and allogeneic grafts by hematoxylin and eosin staining, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining, and radiolabeled-annexin V in vivo imaging. Granzyme B and FasL were expressed in all allogeneic transplants, including those depleted of CD8+ T cells, indicating that a mononuclear cell other than a CD8+ T cell can be the source of these molecules during allograft rejection. Activation of the caspase cascade was detected in all rejecting allografts. Caspases 3, 8, and 9 were activated at similar significantly elevated levels in both allogeneic and CD8+ T cell-depleted liver grafts. CONCLUSION: These data indicate that in the absence of CD8+ T cells an alternative pathway, associated with granzyme B and FasL expression and activation of the caspase cascade, can mediate apoptosis and graft rejection.     

负载肿瘤抗原的DC疫苗体外诱导的特异性抗膀胱癌效应研究

目的 探讨负载膀胱癌抗原成分树突状细胞(dendritic cells,DC)疫苗的制备和体外诱导T淋巴细胞特异性杀伤膀胱癌细胞的作用.方法 冻融法制备EJ细胞裂解物抗原成分,体外培养的人外周血单个核细胞(hu-PBMC)在rhGM-CSF、rhIL-4、TNF-α诱导下分化出DC,负载EJ细胞裂解物抗原后制备膀胱癌DC疫苗;免疫磁珠分离法从人免疫重建Balb/c裸小鼠脾脏组织中分离CD3+ T淋巴细胞,3H-TdR掺入试验测定DC疫苗刺激自体T淋巴细胞增殖的能力,51Cr释放试验检测DC疫苗诱导的T细胞对EJ细胞的杀伤作用.结果 Hu-PBMC在细胞因子rhGM-CSF、rhIL-4和TNF-α的刺激下分化为成熟DC,负载EJ抗原的DC疫苗体外可使同源T淋巴细胞活化,增殖指数增加,活化的T淋巴细胞对EJ细胞的杀伤率为(62.58±6.13)%,和对照组比较差异有统计学意义(P＜0.05).结论 负载膀胱癌冻融抗原的DC疫苗体外可诱导人T淋巴细胞活化增殖,对EJ细胞有明显的杀伤作用.     

强直性脊柱炎患者骨髓间充质干细胞的生物学及免疫学特性

目的:探讨强直性脊柱炎(AS)患者骨髓间充质干细胞(BMSCs)的生物学及免疫学特性,为进一步阐明AS的发病机制和寻找新的治疗靶点提供理论依据。方法 :选取37例活动期AS患者(AS组),男34例,女3例,平均年龄(24.3±5.4)岁,HLA-B27均为阳性;49例健康志愿者作为对照组(HD组),男43例,女6例,平均年龄(25.7±4.9)岁;其中HLA-B27阴性44例(HD1组),HLA-B27阳性5例(HD2组)。从每例受检者髂后上棘穿刺采集骨髓组织,分离BMSCs,培养扩增至第3代,以1×104/ml的浓度接种于96孔板中,100μl/孔,从第1天开始每日取3孔进行细胞计数,共计12d,绘制生长曲线;每日取3孔经MTT处理后测定吸光度值,绘制细胞活力曲线,观察BMSCs的生物学特性。使用流式细胞仪检测各受检者BMSCs的细胞表面表型。将第3代BMSCs细胞接种于U形底96孔板,培养4h后使用60Co照射30Gy;取健康志愿者外周血采用密度梯度法分离单个核细胞(PBMCs),加入细胞培养液,计数后按BMSCs∶PBMCs 1∶20、1∶10、1∶5、1∶2、1∶1的比例接种于已接种BMSCs的96孔板,共培养5d,观察双向混合淋巴细胞反应情况;同样获取PBMCs,计数后同样以5个比例接种于96孔板,加入植物血凝素(PHA)4μg/ml,充分接触后共培养5d,观察淋巴细胞增殖反应情况。对组间进行统计学比较。结果:AS组、HD1和HD2组第3代BMSCs体外培养1~12d时的增殖能力、细胞活力无显著性差异(P>0.05);三组细胞表面表型均为高水平表达CD105、CD73和CD90,不表达CD45、CD34、CD14和HLA-DR。HD1组和HD2组BMSCs与不同比例PBMCs共培养的双向混合淋巴细胞反应和PHA刺激的淋巴细胞增殖反应均无显著性差异(P>0.05);AS组与HD组比较有显著性差异(P<0.05)。结论:AS患者BMSCs的生物学特性无明显改变,但其免疫调节功能明显下降,其可能在AS的发病机制中扮演重要角色。     

Human allogeneic vascular rejection after arterial transplantation and peripheral lymphoid reconstitution in severe combined immunodeficient mice

BACKGROUND: Interspecies differences create important shortcomings in existing animal models used to describe in vivo events responsible for allograft rejection. Alloimmune destruction of human dermal microvessels, histologically consistent with rejection, has been demonstrated in human skin-grafted severe combined immunodeficient (SCID) mice receiving allogeneic human peripheral blood mononuclear cells (PBMC). We have now documented human alloimmune injury in a vascularized, SCID-human arterial transplantation model. METHODS: Fresh human artery was used to replace the CB.17 SCID/beige mouse infrarenal aorta. Seven days later, 3x10(8) human PBMC were administered intraperitoneally, and lymphocyte engraftment was considered successful when circulating human CD3+ cells were later identified in peripheral blood. RESULTS: Forty-six of 49 (94%) mice undergoing transplantation survived, including 14 controls with arterial grafts receiving no PBMC. Twenty-eight of 32 mice demonstrated circulating human CD3+ cells, 14 days after PBMC administration. Animals were killed at 14, 21, or 28 days after receiving allogeneic PBMC, and arteries were recovered for histology and immunohistology. All 14 control mice had patent transplanted grafts with normal vascular histology and no lymphoid infiltration. Damage to transplanted arteries among lymphocyte-engrafted mice was apparent by 14 and 21 days in some animals, whereas 16 of 22 exhibited moderate to severe intimal, medial, and/or adventitial lymphocytic infiltration with intimal expansion by day 28. The infiltrate consisted of HLA-A, -B, -C+, and -DR+, human CD3+ cells, approximately equally distributed as CD4+ and CD8+ subsets. Some infiltrating lymphocytes were cytolytic cells as demonstrated by perforin staining. The endothelium of transplanted human arteries exhibited endothelialitis, and the endothelial cells stained intensely with anti-HLA-A, -B, -C and anti-HLA-DR antibodies. The expanded intima was predominantly smooth muscle cells, staining positively for smooth muscle alpha-actin, HLA-A, -B, -C and HLA-DR. Medial necrosis was not observed. CONCLUSION: The results provide evidence of alloimmune-mediated vascular rejection in this human arterial transplantation model.     

Inhibition of human dendritic cell functions by methylprednisolone.

BACKGROUND: The aim of this study was to better define how glucocorticoids influence primary human T cell responses. Dendritic cells (DC*) are the most effective antigen presenting cells able to activate naive T cells. Previous studies have shown that dexamethasone impaired the function of murine DC. Here, we analyzed how methylprednisolone (MP) might affect the function and maturation of human DC. METHODS: Human DC were generated from peripheral blood mononuclear cells cultured in granulocyte macrophage-colony stimulating factor and interleukin (IL)4. DC maturation was induced either by lipopolysaccharide (LPS) or by fibroblast transfected with the CD40-ligand gene (3T6-CD40L). DC phenotype was characterized by flow cytometric analysis, their cytokine production by ELISA. The ability of DC to activate naive T cells was evaluated in mixed leukocyte reactivity. RESULTS: Although MP did not affect viability of DC, it enhanced their antigen uptake and down-regulated their basal expression of CD86. The expression of CD80 and CD54 by DC was slightly decreased and HLA-DR expression was not modified. MP prevented LPS-induced DC maturation as assessed by the inhibition of CD86, CD80 and CD54 up-regulation, CD83 induction and production of TNF-alpha, IL-6, and IL-12. In contrast, when DC were stimulated by 3T6-CD40L, MP prevented only the synthesis of IL-12. Moreover, MP-treated DC were deficient in their ability to elicit proliferative responses of CD4+CD45RA+ allogeneic T cells as well as their synthesis of interferon (IFN)-gamma, IL-5, and IL-13. CONCLUSION. Glucocorticoids exert potent suppressive effects on human DC and thereby inhibit the induction of primary T cell responses.     

Generation of dendritic cells in vitro from peripheral blood mononuclear cells with granulocyte-macrophage-colony-stimulating factor, interleukin-4, and tumor necrosis factor-alpha for use in cancer immunotherapy.

OBJECTIVE: The purpose of the study was to characterize the requirements in terms of precursors, developmental pathways, and media for the generation of large numbers of mature dendritic cells (DC) under conditions acceptable for use in adjuvant, active immunotherapy strategies for surgically treated malignancies. SUMMARY BACKGROUND DATA: Although limited previously by the small numbers accessible, DC-based immunotherapies for malignancy have become more realistic with the development of methods for efficiently generating larger numbers of DC from peripheral blood mononuclear cells (PBMC) in vitro, but these methods rely on clinically unacceptable culture conditions (such as inclusion of fetal bovine serum), necessitating the development of methods for generating functionally equivalent DC in serum-free conditions. METHODS: Plastic-adherent PBMC (from healthy donors and patients with cancer) were incubated for 7 days with granulocyte-macrophage-colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) with and without tumor necrosis factor-alpha (TNF-alpha) in fetal bovine serum-containing and serum-free media and were analyzed by Wright's stain for morphology, flow cytometry for phenotype, and mixed lymphocyte reaction for allostimulatory function. RESULTS: Growth in either serum-containing or serum-free media supplemented with GM-CSF and IL-4 yielded a similarly heterogeneous population of cells, 6% to 10% of which had the morphology (large cells with thin projections), immunophenotype (including CD83+), and function of mature DC. Tumor necrosis factor-alpha significantly augmented the number of these mature DC, whereas preculture depletion of CD14+ PBMC virtually eliminated them. CONCLUSIONS: Generation of mature DC in the authors' serum-free clinically applicable conditions is similar to serum-containing conditions and requires CD14+ precursors, differentiation through a CD14-CD83- immature stage under the influence of GM-CSF and IL-4, and maturation into a CD83+ DC under the influence of TNF-alpha.     

Induction of Porcine Regulatory Cells by Mycophenolic Acid-Treated Dendritic Cells

Tolerance induction in murine allogeneic transplantation is relatively easy, often by induction of regulatory T cells (Treg). Unfortunately, the implementation of these models in clinical situations has not yielded reliable protocols of tolerance induction in humans. Our project sought to create a preclinical model of tolerance induction in large animals. Our current efforts seek to induce and characterize porcine Treg, obtaining dendritic cells (DC) able to preferentially stimulate them. DCs were differentiated from blood monocytes with porcine recombinant interleukin-4 (IL-4) and granulocyte-macrophage colony-stimulating factor (GM-CSF) for 6 days. These DCs were then stimulated by human CD40 ligand-transfected L cells with or without mycophenolic acid (MPA) for 48 hours. We analyzed surface marker expression, cytokine synthesis, and ability to stimulate allogeneic peripheral blood mononuclear cells (PBMC). The porcine lymphocytes underwent 4 rounds of 1-week stimulation with allogeneic DC treated or not with MPA. At the end of this coculture we analyzed their capacity to suppress allogeneic PBMC proliferation induced by mature DC. Our results showed that porcine DCs pretreated with MPA display a low expression of B7 costimulatory molecules, produce low levels of IL-12, and induce weak proliferation of allogeneic lymphocytes. Moreover, after 4 rounds of stimulation with MPA-treated DCs, PBMCs were able to inhibit an alloreactive response. These preliminary results suggested induction of a regulatory T-cell population that we are currently seeking to characterize.     

HLA-specific B cells: II. Application to transplantation

BACKGROUND: Differences in the antibody response to allogeneic transplantation exist between groups defined by race or gender. These differences may reflect differences in immune competency and/or exposure to alloantigens. We have investigated the frequencies and phenotypes of HLA-specific B cells to address those possibilities. METHODS: HLA-specific B cells were identified by staining with HLA tetramers (tet) as described previously and the distribution of CD27 and CD38 among those cells were measured in groups defined by various parameters. Possible correlation between frequencies of HLA-specific B cells and production of HLA-specific antibody after transplantation was also investigated. RESULTS: We found no correlation between the frequencies of CD27+tet+ (33%-44% vs. 34%-36%) or CD38+tet+ (57%-65% vs. 59%-66%) B cells and a previous mismatch for the HLA antigen of the tetramer. However, there was an increase in CD38+tet+ B cells among patients making antibody to the tetramer antigen (67%-72% vs. 53%-56%). Blacks had lower frequencies of CD27+ B cells than did whites (11.8% vs. 28.9%, P=0.003), but had greater increases of these cells among tet+ cells than did whites. There was a higher frequency of tet+ B cells among patients who developed "new" antibody to the HLA antigen (3.9%-8.6%) of the tetramer after transplantation than among those who did not (1.1%-3.7%). CONCLUSIONS: The phenotype of HLA-specific B cells reflects current or historic sensitization to HLA and may reflect inherent differences between groups defined by race and/or gender. The frequencies of HLA-specific B cells may predict patients at risk for production of donor-specific antibody after transplantation.     

Infiltration of activated dendritic cells and T cells in renal cell carcinoma following combined cytokine immunotherapy

OBJECTIVES: In a phase I study the feasibility, toxicity and immunological effects of peri-operative cytokine immunotherapy of renal cell carcinoma were studied. Main goals were to determine the maximal tolerable dose and detailed in situ analysis of tumor infiltrates. METHODS: Fifteen patients with renal cell carcinoma, undergoing nephrectomy, received subcutaneous immunotherapy, consisting of low-dose IL-2, IFNalpha and GM-CSF, from day -3 prior, until day +5 following surgery in a dose escalation study. Infiltrates from resected tumor tissues from patients undergoing immunotherapy or control patients that underwent nephrectomy only, were examined using quantitative immunohistological analysis and 3-color immunofluorescence staining and confocal laser scanning microscope analysis. RESULTS: Toxicity was limited and the maximal tolerable dose was established. In peripheral blood an increase was found in total lymphocytes, (activated) T cells, NK cells and monocytes. Quantitative immunohistological analysis of tumor infiltrates showed enhanced numbers of CD3+ T cells, S100+ DC, CD83+ DC and IL-2 receptor positive cells (4-fold, 2-fold, 10-fold and 20-fold, respectively, compared to controls). In treated patients preferential invasion was observed of TNFalpha positive CD8+ T cells and DC, positive for DC-SIGN (CD209), CD83, CD80, IL-12 and the DC specific chemokine, DC-CK1 (CCL18). CONCLUSIONS: These findings show increased infiltration of activated, mature DC and functionally active CD8+ T cells in renal tumors, which may suggest clinical potential of cytokine immunotherapy.     

Allogeneic reaction induces dendritic cell maturation through proinflammatory cytokine secretion

BACKGROUND: A bone marrow transplantation conditioning regimen is known to activate host dendritic cells (DC), which then become able to initiate graft-versus-host disease (GVHD) by presenting alloantigens. In this article, the authors addressed whether the alloreaction could reciprocally maintain DC in an activation state through secretion of proinflammatory cytokines. METHODS: Skin biopsy specimens from GVHD patients were analyzed for the presence of DC. Supernatants collected from primary major histocompatibility antigen (allogeneic mixed leukocyte reaction [MLR] supernatant [SN]) or secondary minor histocompatibility antigen-mismatched mixed lymphocyte reactions were used to culture cytokine-promoted immature (im) DC. DC phenotype, function, and migration were analyzed. RESULTS: Immunostaining from GVHD skin biopsy specimens showed a deficit of Langerhans cells (LC) in the epidermis but the presence of mature DC in the dermis. Because LC should have recovered in the epidermis by this time, the authors then addressed whether the allogeneic reaction could maintain DC in an activation and migratory state, through secretion of inflammatory cytokines. With this aim, cytokine-mediated imDC were exposed to alloMLR-SN for 2 days. The authors observed that DC increased their expression of CD80, CD86, CD40, and human leukocyte antigen (HLA)-DR and neoexpressed CD83, DC-LAMP/CD208, and CCR7. At the functional level, alloMLR-SN-treated DC lost their ability to capture dextran, improved their allostimulatory capacity, and migrated in response to macrophage inflammatory protein 3beta. Interestingly, SN collected from secondary HLA-identical but minor histocompatibility antigen-mismatched MLR induced almost equivalent DC phenotypic maturation. CONCLUSIONS: The authors' results show that the allogeneic reaction leads to maturation and migration of DC through proinflammatory cytokine secretion. This might contribute to the impairment of LC reconstitution in the skin of patients with GVHD.     

In vitro immunogenicity of cadaver donor bone marrow cells used for the induction of allograft acceptance in clinical transplantation.

BACKGROUND: The cascade of immunological effects brought about by donor bone marrow cell (DBMC) infusions to induce allograft acceptance in clinical transplantation is not fully understood. Aside from acting as immune responding and regulatory cells, the infused DBMC also may sensitize the recipient to the donor antigens. METHODS: To analyze this stimulatory activity of DBMC, in vitro mixed lymphocyte cultures (MLC) and cell-mediated lymphocytotoxicity (CML) culture systems analogous to the transplant model with DBMC infusion were used. RESULTS: When responding peripheral blood lymphocytes (PBL) from normal volunteers were placed in culture with suspensions of Ficoll-purified, T cell-depleted, un-irradiated allogeneic DBMC (NT-DBMC), a reaction was seen in both MLC and CML. However, when compared to allogeneic spleen cells as stimulating cells, the responses to NT-DBMC were of markedly lower magnitude and were not seen when the NT-DBMC was irradiated (3000 R). When responding PBL were stimulated with either NT-DBMC that had been previously cultured with irradiated cells from the responders for 1 week (activated NT-DBMC), NT-DBMC further depleted of CD15+ and glycophorin A-positive cells (NT-LP/DBMC), or purified CD34+ and CD2+ DBMC subsets, stronger lymphoproliferative and cytotoxic responses were observed. Moreover, these responses were not abrogated by irradiation of the stimulating DBMC subpopulations. Depletion of antigen-presenting cells by positive selection of CD3+ cells from the responding PBL abrogated MLC and CML reactivity, even when purified NT-LP/DBMC, the most stimulatory cells, were used. This latter observation was in contrast to the responses seen with cultures containing allogeneic stimulating spleen cell populations. This indicated the requirement for indirect alloantigen presentation, i.e., the failure of these DBMC to stimulate by direct alloantigen presentation. NT-DBMC was able to stimulate responding PBL in secondary MLC and CML responses with an equivalent magnitude, irrespective of whether the stimulators were spleen cells or NT-DBMC. Finally, the MLC and CML responses were inhibited by tacrolimus (FK506), mycophenolic acid (MPA), and cyclosporine (CsA) in a dose dependent manner, in contrast to previously observed refractoriness of DBMC preparations to these agents if DBMC was tested as responder cells or in modulatory assays. CONCLUSIONS: These results indicate that DBMC are able to function as effective in vitro stimulators, but only by indirect antigen presentation, and that the immune responses mediated by them can be down-regulated by their own inherent suppressive nature, an effect that can be enhanced by the presence of immunosuppressive drugs.     

Soluble CD83 inhibits acute rejection by up regulating TGF-β and IDO secretion in rat liver transplantation

BackgroundAllogeneic transplantation immune tolerance is currently a hot research issue and soluble CD83(sCD83) is a novel immunomodulator with great potential in inducing transplantation tolerance.ObjectiveTo investigate the mechanism of the immune tolerance effect of sCD83 on rat liver transplantation.MethodA rat liver transplantation model was established to study the effects of sCD83 on the expression levels of IL-2, IL-10, and TGF-β in peripheral blood and the mRNA expressions of foxp3, TGF-β, and Indoleamine 2,3-dioxygenase (IDO) in liver. The expression changes of costimulatory molecules CD80, CD86, and MHC-II on the surface of DC cells and the expressions of IDO ⁺ DC cell, TGF-β ⁺ CD4 ⁺ T cell, and CD4 ⁺ CD25 ⁺ Foxp3 ⁺ T cell were analyzed and compared.ResultssCD83 alleviated the rejection activity index (RAI) of rat liver transplantation in the early stage, increased the expressions of TGF-β, IL-10 in peripheral blood and the mRNAs of IDO, TGF-β and foxp3 in the transplanted liver, and down-regulated the expressions of MHC-II, CD86, and CD80 in DC cells, resulting in significant increased numbers of tolerogenic TGF-β ⁺ CD4 ⁺ T cells, Treg cells, and IDO ⁺ DC cells with low expression.ConclusionsCD83 inhibited acute rejection after liver transplantation in an allogeneic rat, and the mechanism was associated with the effect that sCD83 increased the expression of TGF-β, activated IDO immunosuppressive pathway, and increased tolerogenic DC cells and Treg cells.     

Ex Vivo‐Expanded Cynomolgus Macaque Regulatory T Cells Are Resistant to Alemtuzumab‐Mediated Cytotoxicity

Alemtuzumab (Campath‐1H) is a humanized monoclonal antibody (Ab) directed against CD52 that depletes lymphocytes and other leukocytes, mainly by complement‐dependent mechanisms. We investigated the influence of alemtuzumab (i) on ex vivo‐expanded cynomolgus monkey regulatory T cells (Treg) generated for prospective use in adoptive cell therapy and (ii) on naturally occurring Treg following alemtuzumab infusion. Treg were isolated from PBMC and lymph nodes and expanded for two rounds. CD52 expression, binding of alemtuzumab and both complement‐mediated killing and Ab‐dependent cell‐mediated cytotoxicity (ADCC) were compared between freshly isolated and expanded Treg and effector T cells. Monkeys undergoing allogeneic heart transplantation given alemtuzumab were monitored for Treg and serum alemtuzumab activity. Ex vivo‐expanded Treg showed progressive downregulation of CD52 expression, absence of alemtuzumab binding, minimal change in complement inhibitory protein (CD46) expression and no complement‐dependent killing or ADCC. Infusion of alemtuzumab caused potent depletion of all lymphocytes, but a transient increase in the incidence of circulating Treg. After infusion of alemtuzumab, monkey serum killed fresh PBMC, but not expanded Treg. Thus, expanded cynomolgus monkey Treg are resistant to alemtuzumab‐mediated, complement‐dependent cytotoxicity. Furthermore, our data suggest that these expanded monkey Treg can be infused into graft recipients given alemtuzumab without risk of complement‐mediated killing.     

CD103分子介导CD8+T淋巴细胞对同种胰岛移植物的损伤

目的 检验CD103分子是否介导了CD8+T淋巴细胞对同种移植胰岛的免疫损伤.方法 用流式细胞仪检测野生型C57BL/6小鼠外周血CD8+T淋巴细胞表达CD103的情况.以Balb/c小鼠为供者,C57BL/6小鼠为受者,制作同种胰岛移植模型.受者分为3组:M290-SAP组小鼠注射CD103免疫毒素M290-SAP;M290组小鼠注射抗CD103单克隆抗体M290;另以仅接受胰岛移植、不注射任何药物的小鼠为未处理组.检测移植胰岛CD3、CD8、CD44和CD103阳性细胞的表达,检测肠系膜淋巴结中CD3、CD8和CD103阳性细胞的表达.移植物功能丧失或观察期结束时获取移植胰岛,行HE染色和免疫组织化学染色.结果 野生型C57BL/6小鼠外周血的CD8+T淋巴细胞中有44.06%表达CD103.未处理组移植胰岛浸润的细胞成分中有29%的CD8+T淋巴细胞表达CD103.M290-SAP组小鼠淋巴细胞不仅丧失了CD103的表达,而且CD8+T淋巴细胞的绝对数量也减少,该组小鼠血糖稳定时间超过100 d(未处理组为13 d,P＜0.05),移植胰岛组织学形态良好.结论 CD8+T淋巴细胞免疫损伤同种移植胰岛必须表达CD103,CD103有可能成为胰岛移植抗排斥反应治疗的新靶点.

Abstract：

Objective To test whether the CD103 molecule mediates CD8+ T lymphocytes on allogeneic islet graft immune injury. Methods By using flow cytometry, the expression of CD103 in peripheral CD8+ T lymphocytes in wild-type C57BL/6 mice was detected. Allogenic islet transplantation models were made using Balb/c donor mice and C57BL/6 recipient mice. Recipients were divided into 3 groups: M290-SAP-treated mice were injected with CD103 immunotoxin M290-SAP; M290-treated mice were injected with CD103 monoclonal antibody M290; untreated mice were only transplanted islet without any drug treatment. CD3, CD8, CD44 and CD103 positive cells were counted in islet allograft infiltrative lymphocytes. CD3, CD8, and CD103 positive cells were measured in the mesenteric lymph node. The islet allografts were removed and subjected to HE staining and immunohistochemical staining at the time of graft loss or the end of the observation period. Results 44. 06% peripheral CD8+ T cells expressed CD103 in wild-type C57BL/6 mice. 29 % CD8+ T cells expressed CD103 in the infiltrative lyrnphocytes of islet allografts in the untreated mice. In M290-SAP-treated mice, the lymphocytes had no CD103 expression and the absolute number of CD8+ lymphocytes was decreased as well The blood glucose was maintained stable for more than 100 days (13 days in untreated group, P＜0.05) in the M290-SAP-treated mice. Moreover, the transplanted islets retained intact. Conclusion CD103 expression is required for destruction of pancreatic islet allograft by CD8+ T cells. CD103 might provide a novel target for therapeutic intervention in islet allograft rejection.     

异源骨髓间充质干细胞抑制树突状细胞活化杀伤细胞的增殖

目的 通过共培养异源的人骨髓间充质干细胞和树突状细胞活化的细胞因子激活的杀伤细胞(DC-CIK细胞),观察DC-CIK细胞的细胞周期,初步探讨骨髓间充质干细胞的免疫调节机制.方法 采用Ficoll密度梯度离心法分离、培养健康骨髓间充质干细胞和外周血单个核细胞,用多种细胞因子诱导培养外周血单个核细胞中贴壁和悬浮细胞分别为树突状细胞和杀伤细胞.将骨髓间充质干细胞与DC-CIK细胞以1∶5,1∶10,1∶20共培养4 d,采用流式细胞术检测DC-CIK细胞的细胞周期.结果 骨髓间充质干细胞呈长梭形,表达CD+29CD+444双阳性的细胞为93.6%,实验选用第三代后的细胞.在培养第9天树突状细胞表达CD1α人类白细胞Ⅱ类抗原(HLA-DR+)]双阳性细胞数为98.5%.DC-CIK细胞表达CD+3CD+56的细胞数为(29.2±12.2)%.骨髓间充质干细胞使DC-CIK细胞滞留在G0/G1期,且与细胞比例呈正相关.以1∶5,1∶10,1∶20的比例共培养4 d的DC-CIK细胞的G0/G1期和S期分别为(91.0±3.3)%和(2.8±0.6)%,(88.7±3.0)%和(5.1±2.8)%,(83.7±1.7)%和(8.7±3.4)%.对照组(同步化DC-CIK细胞)为(73.4±1.0)%和(17.4±0.6)%.结论 骨髓间充质干细胞可通过抑制DC-CIK细胞的细胞周期而发挥免疫调节作用.