Dendric Cells Research Articles

Regulative effects of regulatory T cells on dendric cells in peripheral blood and deciduas from unexplained recurrent spontaneous abortion patients

To study the effect of CD(4)(+)CD(25)(+) regulatory T(Tr) cells on dendric cells (DC) in peripheral blood and deciduas from unexplained recurrent spontaneous abortion (URSA) patients. Four URSA patients (abortion group) and 4 normal early pregnant women (control group) were enrolled in this study. Tr cells and DC in the peripheral blood and deciduas were isolated using Ficoll density gradient centrifugation and magnetic cell sorting (MACS). DC were cultured alone (DC alone) or in combination with Tr cells (DC + Tr) for 6 days, during which the release of interferon (IFN)-gamma and interleukin (IL)-10 in the medium was subsequently measured by enzyme linked immunoadsorbent assay (ELISA). (1) Peripheral blood: there was no significant difference in IFN-gamma level between DC alone (23.2 +/- 0.7) ng/L and DC + Tr (22.5 +/- 3.0) ng/L in abortion group (P > 0.05). The similar level of IL-10 was observed between DC alone (37 +/- 7) ng/L and DC + Tr (35 +/- 4) ng/L in abortion group (P > 0.05). IL-10 level, but not IFN-gamma, was significantly higher in DC alone (54 +/- 20) ng/L than that in DC + Tr (36 +/- 9) ng/L in control group (P < 0.01). (2) Deciduas: there was no significant difference in IFN-gamma level between DC alone (23.4 +/- 2.6) ng/L and DC + Tr (24.4 +/- 2.5) ng/L in abortion group (P > 0.05). Moreover, Similar IL-10 level was found between DC alone (28 +/- 7) ng/L and DC + Tr (25 +/- 5) ng/L in abortion group (P > 0.05). IFN-gamma level in DC alone (30.7 +/- 4.6) ng/L was significantly higher than that in DC + Tr (22.6 +/- 3.8) ng/L in control group (P < 0.01); whereas IL-10 level was much lower in DC alone (27 +/- 6) ng/L than that in DC + Tr (31 +/- 9) ng/L in control group (P < 0.05). The decreasing of immunosuppressive function of Tr cell of URSA patients affect its regulation on DC, resulting in imbalance of Th1/Th2 and abnormality of maternal-fetal immuno-tolerence in URSA.

Therapeutic Effectiveness of Adaptive T-Cell Transfer for Minimal Residual Mantle Cell Lymphoma Following High Dose Therapy.

Mantle cell lymphoma (MCL) is the most aggressive B-cell malignancy with an overall survival of less than four years. Although high-dose therapy followed by stem cell transplantation is effective in reducing the tumor burden and increasing the survival, the patients eventually relapse due to residual lymphoma. Therefore effective therapeutic modalities are needed to target residual MCL. In this study we have developed an immune-based approach to treat minimal residual MCL. HLA matched normal donor mononuclear cells were used to generate dendric cells in vitro. Following characterization, the dendritic cells were fused with the MCL cell line Granta 519 cells to create DC/MCL hybrids. The hybrids were then used to stimulate T cells from the same donor to generate MCL-specific cytotoxic T lymphocytes (CTL). The CTLs were tested for their MCL-specific cytotoxic abilities in vitro against MCL target cells and compared to control T cells or DC primed with MCL lysate or DCs transfected with MCL RNA. HLA matched human breast cancer cell line MDA-231 was used as an irrelevant tumor target. The in vitro results showed the highest MCL specific cytotoxic effects of CTLs generated using DC-MCL hybrids for immunostimulation. As a logical next step, in vivo therapeutic affects the MCL-specific CTLs were tested using a preclinical animal model. Four groups of NOD-SCID mice, with a minimum 10 mice per group, were transplanted with Grant-519 human MCL cell line intravenously. MCL bearing mice were treated with combination chemotherapy (CHOP)over three days followed by transplantation of 1 ×106 mononuclear cells. Ten days after, mice were transplanted with 3 ×106 adoptive T cells weekly for four weeks. The results of the in vivo studies showed that, adoptively transferred T cells that had been stimulated with DC/MCL hybrids were able to significantly inhibit tumor growth in the liver (p = 0.005), kidneys (p = 0.001), and lungs (p= 0.001) of mice with minimal residual MCL compared to control tumor bearing animals as determined by analyzing tumor burden in the organs using virtual images and Neuroinformatica software. When combined with CHOP chemotherapy, adoptively transferred T cells were able to significantly (P = 0.001) extend the survival of the mice by significantly further reducing the tumor burden as compared to mice only receiving the chemotherapy plus unmanipulated T cells. Specificity of the CTL mediated response was also confirmed by cytokine profiling in vitro and in vivo. In summary, we have clearly shown that antigen-primed DCs can be used to activate MCL-specific T cells which, when administered adoptively, are effective in treating minimal residual MCL. Thus these studies lay foundation for a PhaseI/II clinical trial.(This study was supported by the Lymphoma Research Foundation, New York, NY).

Modulation of Dendritic Cell Function by Naive and Regulatory CD4+ T Cells

The consequences of interactions between dendric cells (DCs) and either naive CD4+ T cells or regulatory CD4+CD25+ T cells on the expression of proinflammatory IL-6 and anti-inflammatory IL-10 in DC were examined over a period of 12 h, spanning the time frame during which stable T cell-DC interactions shape the development of tolerance and immunity in vivo. We demonstrate that the basal production of IL-6 and IL-10, which is initiated following DC stimulation with LPS, is modified in distinctly different ways by interaction with the two T cell populations. Naive CD4 T cells skew DC cytokine production toward IL-6 and suppress IL-10, whereas CD4+CD25+ T cells have the opposite effect. CD8 T cells or memory CD4 T cells do not influence basal cytokine production by stimulated DC. The effect of CD4+CD25+ T cells is dominant in coculture with naive CD4 T cells as long as inflammatory LPS is absent; the addition of LPS abrogates the suppression of IL-6. However, the modulating influence of CD4+CD25+ T cells remains evident in the enhancement of IL-10 production. Thus, mutual interactions between DC and CD4+ T cell subpopulations following contact with pathogens are likely to influence the strength and quality of incipient immune responses in the local microenvironment.

Reduced blood BDCA-2+ (lymphoid) and CD11c+ (myeloid) dendritic cells in systemic lupus erythematosus

Type 1 IFN is thought to be implicated in the autoimmune process of SLE. Plasmacytoid dendric cells (DC), which are natural IFN-alpha producing cells, play a pivotal epipathogenic role in SLE. The present study was undertaken to investigate the phenotypic characteristics of peripheral blood DC in SLE patients in comparison with those of healthy controls. Samples from 20 SLE patients and 18 healthy controls were studied. Three-colour flow cytometry was performed to identify myeloid DC, as CD11c(+) lineage marker(-), and HLA-DR(+) cells and plasmacytoid DC, as BDCA-2(+) linage marker(-), and HLA-DR(+) cells. We used the whole blood 'lyse/no-wash' procedure, which allows precise counting of peripheral blood DC. BDCA-2(+) plasmacytoid DC and CD11c(+) myeloid DC were reduced in SLE patients compared with controls. Similarly, BDCA-3(+) DC were reduced in SLE patients. These results indicated that SLE patients had a reduced number of both BDCA-2(+) plasmacytoid DC and CD11c(+) myeloid DC. These alternations of the DC subset may drive the autoimmune response in SLE.

Anatomical and cellular basis of immunity and tolerance in the intestine.

Anatomical and cellular basis of immunity and tolerance in the intestine.

Immunohistochemical analysis of effects of cyclosporin A on gingival epithelium

Cyclosporin A (CSA)-induced gingival overgrowth was immunohistochemically compared with that phenytoin-induced and nonspecific inflammatory gingiva, and CSA concentration was determined for dental plaque. Leu-6+ epithelial dendric cells (EDC) were found to significantly decrease in number in CSA-induced gingival overgrowth, while the ratio of HLA-DR+ EDC to Leu-6+ EDC did not change significantly. The expression of class II major histocompatibility complex antigens, such as HLA-DR, -DP and -DQ on keratinocytes did not change by CSA-treatment. Leu-4+ mononuclear cells in CSA-induced gingival overgrowth were located primarily in the connective tissue far outside the epithelium. CSA concentration was much higher in dental plaque than in blood and other tissues. Immune response thus appears to be suppressed in the epithelial layer of CSA-induced gingival overgrowth through decrease in Leu-6+ HLA-DR+ EDC and T cell infiltration, both due to CSA in dental plaque. DNA polymerase alpha was detected in much fewer basal keratinocytes of CSA- and phenytoin-induced gingival overgrowth. Epithelial hyperplasia may thus be not due to increased keratinocyte proliferation, but rather to enhanced keratinocyte life span.