Effects of CpG ODN on dendritic cells in anti-hepatocarcinoma action

AIM: To study the effect of oligonucleotides containing unmethylated CpG motif (CpG ODN) on mouse bone marrow-derived dendritic cells (BMDCs) in anti-HcaF cytotoxicity. METHODS: BMDCs were stimulated by CpG ODN in combination with tumor antigen (TAg). The expression of CD80 on BMDC surface was analyzed by FCAS. Level of IL-12 (p70) in supernatants of BMDC culture was detected by ELISA. The proliferation of T cells was examined by MTT assay. Cytotoxicity of CTL induced by CpG ODN combining with TAg was detected by MTT assay. RESULTS: CpG ODN combining or not combining with TAg up-regulated the expression of CD80 on BMDC surface and stimulated BMDCs to produce a high level of IL-12. CpG ODN-activated BMDC promoted the proliferation of T cells. CTL induced by CpG ODN in combination with TAg appeared strong specific cytotoxicity on Hca-F cells. CONCLUSION: CpG ODN may effectively induce the functional maturation of mouse BMDC in vitro. CpG ODN in combination with TAg can enhance the anti-HcaF cytotoxicity of CTL.     

Recent advances in the correlations between dendritic cells and regulatory T cells

Dendritic cells (DCs), representing a heterogenous population of professional antigen-presenting cells, are the initiators and modulators of the immune responses. Studies indicate that regulatory T cells contribute to immune nullipotency and immune suppression via cell-cell contact or cytokine secretion. These two kinds of cells may be valuable tools for modulating immunity in the setting of auto-immunity, cancer, chronic viral infections and graft rejection, etc. Here we discuss the current knowledge on the functions of regulatory T cells and denditic cells-based immunoregulation and the applications.     

Donor dendritic cells treated with B7-1, B7-2 antisense oligonucleotide prolonged mouse cardiac allograft survival

AIM:To investigate the effect of donor bone marrow derived dentritic cell (DC) treated with B7-1, B7-2 antisense oligonucleotide on mouse heart allografe survival time and its mechanism. METHODS: There were 7 groups of C57BL/10J (B10) mouse bone marrow DCs which were treated by 400 nM antisense oligonucleotide target to B7-1, B7-2 mRNA (AS B7-1/2), B7-1 mismatch oligo control, B7-2 mismatch control(mASB7-1/2), lipofectamine only and non-treatment, respectively. Each group of DC were named as ASB7-1 DC, ASB7-2 DC, mASB7-1DC, mAS B7-2DC, and Lipo DC, respectively.RESULTS: Flow cytometer results shown that AS B7-1/2 can inhibit B7-1(CD80)and B7-2 (CD86) molecule express on DC surface, while control groups have no effects. To observe their tolerogenicity in mouse cardiac allograft model, B10→C3H heterotopic heart transplantation were performed. Recepients were received 2×10⁶ of DC injection 7 days before transplantation. Results showed that both AS B7-1DC and AS B7-2 DC can prolong mouse cardiac allograft survival time to (18.6±0.89) days and (23.67±10.73) days, respectively, compared with IL-4 DC .Two mismatch control groups can slightly prolong while oligo DC has no effect. For understanding its mechanism, each group of DC was used as stimulator to stimulated C3H spleen T cell. Results suggested that AS B7-1DC and AS B7-2 DC had less allo-stimulate function, including MLR and generation CTL and IL-2 production than IL-4 DC but control groups have no effect.CONCLUSION: Donor bone marrow derived DC treated with AS B7-1 oligo and AS B7-2 oligo expressed lower level of CD80 and CD86, respectively. These cells can induce allogeneic T cells anergy in vitro and markedly prolong mouse heart allograft survival time in vivo.     

Effects of progesterone on the maturation and immunologic function of dendritic cells from human peripheral blood

AIM: To study the effects of progesterone (P₄) on the maturation and immunologic function of dendritic cells (DCs) from human peripheral blood. METHODS: Cultured DCs were treated with P₄ at doses of 10-7 mol/L and 10-6 mol/L. The morphologic changes were observed under the scanning electronic microscope. The immunophenotypes of DCs in control and treated groups were analyzed by flow cytometry. IL-10 and IL-12 production in culture supernatant was examined by ELISA assay. The capability of the stimulatory activity of the DCs on allogeneic T cells in mixed reaction was tested by incorporation of ［3H］-TdR. RESULTS: Compared with control group, cultured DCs in the presence of P₄ displayed less dendritic pseudopod, expressed low levels of MHC-II, CD40, CD80 and CD86, and exhibited weakly activity in stimulating the proliferation of allogeneic T cells. Increase in IL-10 production and decrease in IL-12 production were observed. CONCLUSION: P₄ exerts negative effect on the maturation and immunologic function in dendritic cells from human peripheral blood.     

Inhibitory effect of NF-κB decoy ODN on expressions of TLR4 and IL-8 in LPS- induced intestinal epithelial cells

AIM: To study the effect of NF-κB decoy oligodeoxynucleotides(ODNs) on TLR4 and IL-8 expression in LPS-induced SW480 cells. METHODS: SW480 cells were cultured in vitro and stimulated for 3 h with LPS (10 μg/L). NF-κB decoy oligodeoxynucleotides mediated by lipofectin 2000 were added into the cell culture for 6 h. The supernatants were collected and messured for IL-8 by ELISA. TLR4 mRNA and IL-8 mRNA were examined by RT-PCR, respectively. The results were compared with control group, Scrambled ODNs group and lipofectin 2000 group. RESULTS: After SW480 cells were stimulated by LPS, TLR4 mRNA, IL-8 mRNA and IL-8 expressions were significantly increased, and the difference compared with control group was obvious. After treated with NF-κB decoy oligodeoxynucleotides, TLR4 mRNA, IL-8 mRNA and IL-8 expressions were significantly inhibited. The Scrambled ODNs group and lipofectin 2000 group had no effect on them. CONCLUSION: NF-κB decoy ODNs will become a new gene drug for treating inflammatory bowel disease(IBD).     

Inhibitive effect of cytomegalovirus infection on immunological functions of dendritic cells

AIM: To investigate the effect of cytomegalovirus (CMV) infection on the immunological functions of dendritic cells (DC) derived from monocytes. METHODS: RT-PCR assay was used to detect the mRNA expression of CMV immediate early antigen (IEA) and glyceraldehyde phosphate dehydrogenase (GAPDH) genes in immature and mature dendritic cell (cmv-imDC, cmv-mDC) infected by 50-folds median tissue culture infective dose (TCID50) of CMV. The expression of early antigen (EA) in cmv-imDC and cmv-mDC was analyzed by indirect immunofluorescence assay. CMV late antigen pp65 was determined by flow cytometry. The allogeneic stimulating capacity of cmv-DC was assayed by mixed lymphocyte reaction (MLR) with BrdU incorporation. RESULTS: The expression of IE mRNA in cmv-mDC was lower than that in cmv-imDCs at 12 h after infection (0.102±0.020 and 0.862±0.124, respectively, P<0.05). EA, primarily localized in nucleus, was found in cmv-imDC (62.32±14.20)% and cmv-mDC (10.78±3.04)% at 24 h (P<0.01). pp65 positive cells in cmv-imDC and cmv-mDC at 72 h were 4.86% and 0.82%, respectively. Compared with untreated mDC, cmv-imDC showed depressed antigen presentation even after stimulated with maturation signal factor LPS (both P<0.05), while cmv-mDC had weaker stimulating capacity only when DC/T cell ratio was 1∶1 (P<0.05). CONCLUSION: CMV efficiently infectes and replicates in imDC. CMV suppresses the antigen presenting capacity of cmv-DC.     

An innate cholinergic system and its regulation in mature dendritic cell

AIM:To investigate whether there was nicotinic acetylcholine receptor subunit α 7(nAChR α 7), choline acetyltransferase(ChAT), acetylcholinesterase(AChE) expression and its regulation in mature dendritic cells(DCs). METHODS:Bone marrow(BM)-derived DCs from healthy BALB/c mice were incubated with rmGM-CSF and rmIL-4, and stimulated to mature with LPS. Meanwhile, light microscope and flow cytometry were used to identify DCs, as well as immunocytochemistry, immunofluorescence, flow cytometry and RT-PCR methods were used to dectect expression of nAChR α 7,ChAT and AChE. Flow cytometry was also used to analyze nAChR α 7 expression with mecamylamine (MEC) in 12 h. RESULTS:Both protein and mRNA expression of cholinergic system nAChR α 7，ChAT and AChE were found in mature DCs. Furthermore, nAChR α 7 distributed principally in cell membrane, while ChAT and AChE in cytoplasm. Protein expression of AChE was stronger as compared with ChAT (P<0.05), and there was a trend toward increasing as compared with nAChR α 7. And then, the expression of nAChR α 7 was down regulated by MEC as compared with the group without MEC stimulation(P<0.05). CONCLUSION:An innate cholinergic system was in mature DCs， which was affected by extrinsic factor (i. e., MEC). And it may be involved in anti-inflammation immune adjustion of cholinergic closed-circuit.     

Immune function of dendritic cells in patients with hepatocellular carcinoma

AIM: To investigate the immune function of dendritic cells (DCs) in patients with hepatocellular carcinoma(HCC). METHODS: The DCs were cultured from human peripheral blood mononuclear cells (PBMC) by using GM-CSF and IL-4 for 7 days. Surface molecules CD86, HLA-DR of DCs were detected by flow cytometry. IL-12 production by DCs and IFN-γ production by T cells was measured with ELISA and ELISPOT, respectively. Allogenic mixed lymphocyte reaction was detected by MTT assay. RESULTS: CD86 expression in DCs in HCC patients were markedly lower than that in health control (91.7％ vs 83.5%, P<0.05). IL-12 production by DCs had no significant difference between the HCC patients and the health control ［(324.6±171.0)ng/L vs (436.5±142.7)ng/L, P>0.05］. However, after stimulated DCs with LPS, IL-12 production in HCC patients was significantly lower than that in health control ［(478.6±142.7)ng/L vs (630.0±151.9)ng/L, P<0.05］. IFN-γ production by T cells and T cell proliferation index (PI) in the HCC patients were all significantly lower than those in health control ［(IFN-γ: 133.4±51.2)103U/L vs (183.0±60.2)103U/L, P<0.05; PI: 2.3±0.7 vs 3.5±0.8, P<0.01］. CTL killing activity assay indicated that DC-induced CTL killing activity in HCC group was significantly lower than that in health group when the E/T ratio was 10∶1 and 20∶1, respectively. CONCLUSION: The immune function of DCs and T cells in the patients with HCC are significantly decreased. The CTL killing activity of HCC group is also markedly decreased.     

Function of dendritic cells in cord blood

AIM: To explore the function of dendritic cells in cord blood.METHODS: Dendritic cell precursor subsets pDC/pDC(CD11c+CD123- /CD11c-CD123+) in cord blood and adult peripheral blood were analyzed gated by CD34-Lin- HLA-DR+ cells and the levels of IL-12p40,IL-10,IFN-γ,IL-4 in the serums were tested by ELISA.RESULTS: The level of IL-12p40 in cord blood serum was higher than that in peripheral blood.pDC1/pDC2,IL-10,IFN-γ,IL-4 in cord blood were similar to that in peripheral blood.CONCLUSION: Function development of dendritic cells in cord blood may be consummate.     

Study on the immunological function of sodium butyrate-induced immature human monocyte-derived dendritic cells

AIM: To investigate the immunological function of sodium butyrate-induced immature dendritic cells in vitro.METHODS: The human monocyte-derived dendritic cells were induced in the presence of human granulocyte macrophage-colony stimulating factor(GM-CSF) and interleukin-4 (IL-4), combined with sodium butyrate. The immunological function of sodium butyrate-induced dendritic cells was detected by the FCM, endocytic activity, T cells stimulatory proliferation capacity, and interleukin-12 (IL-12) production.RESULTS: Sodium butyrate could down-regulate the major histocompatibility complex(MHC) class II and costimulatory molecules of dendritic cells, increase the endocytic activity, induce a stage of T-cell anergey, and inhibit the T helper cell type 1-skewing factor IL-12 production. CONCLUSION: Sodium butyrate inhibits the maturation of dendritic cells and induces production of immature dendritic cells, which may help to explore the machenism of its epigenitic modification.     

Effect of lung cancer cells transfected with interleukin 18 gene on the immunological activity of dendritic cells

AIM: To study the effect of interleukin 18 gene transfected lung cancer cells on the phenotype and immunological activity of dendritic cells (DC). METHODS: A secretive IL-18 expression vector containing IL-12 P40 signal sequence was constructed and transfected into NCI-H460 lung cancer cells. DC induced from human peripheral blood were divided into 4 groups (NT, PV, GT and PD). DC were stimulated by non-transfected NCI-H460 cells, pure vector transfected NCI-H460 cells and IL-18 transfected NCI-H460 cells respectively for group NT, PV, GT, and non-stimulated DC for group PD. CD54, CD80, CD83 and CD86 on DC in the 4 groups were detected with flow cytometry. T cell proliferation stimulated by DC in the 4 groups was assayed with MTT method. IL-12 release in cultured DC supernatant was measured by ELISA. RESULTS: Sequencing result of the secretive IL-18 was correct. The transfected cells expressed IL-18 fusion gene and 18 kD IL-18 protein. DC in GT group expressed more surface molecules than those in other 3 groups. T cell proliferation and IL-12 secretion in GT group were higher than those in other 3 groups. CONCLUSION: IL-18 gene transfected NCI-H460 cell increases surface molecule expressions on DC. It also enhances immunological activity and IL-12 secretion in DC.     

Effects of dendritic cell stimulation on cytotoxic activity of cord blood derived cytokine-induced killer cells,natural killer cells and CD45RO expression in CIK cells

AIM: To investigate the efficacy of dendritic cells (DCs) that augments the cytotoxic activity of cytokine-induced killer (CIK) cells, natural killer (NK) cells from a same donor and the CD45RO expression on CIK cells. METHODS: The expanded killer cells were divided into two groups: group A was pre-cocultured with DCs for 6 days, group B was the control that without any stimulation. Cytotoxicity of CIK and NK cells was measured at different effect-target ratio against K562 and HL-60. CD45RO and CD45RA expression on CIK cells in different groups were detected by flow cytometry. RESULTS: Cytotoxicity of CB derived killer cells was positive correlation with effect-target ratio. The cytotoxicity of group A against HL-60 was higher than that of group B significantly. At 20∶1 effector-target ratio, the lytic activity of group A CIK, NK cells against K562 was higher than that of group B significantly, but no significant difference between them at 10∶1 effector-target ratio. The CD45RO expression on CIK cells in groups A was significantly higher than that in groups B. CONCLUSION: CIK and NK cells cocultured with DCs can augment the killer's cytotoxicity against tumor cells and promote the CD45RO expression on CIK cells.     

Effect of adriamycin combined with sensitized dendritic cells on cervical tumor-bearing mice

AIM：To explore the immunotherapeutic effect of adriamycin (ADM) combined with frozen-thawed antigen-sensitized dendritic cells (DCs) on cervical tumor-bearing mice. METHODS：The U14 cervical cancer model of Kunming mice was established by subcutaneous implantion of U14 cells in axillary fossa. DCs vaccine was prepared by U14 cervical cancer cell frozen-thawed antigen-sensitized mouse bone marrow-derived DCs. Mature phenotype of sensitized DCs was identified by flow cytometry. Tumor-bearing mice were randomly divided into 4 groups and treated for 3 cycles with PBS (control), DCs vaccine, ADM and ADM combined with DCs vaccine, respectively. The tumor volume was evaluated. The tumor weight and the levels of interleukin-2 (IL-2), IL-12 and interferon γ (IFN-γ) in the serum were determined by ELISA on the 21st day. RESULTS：Cancer cell frozen-thawed antigen-sensitized DCs had higher expression levels of CD11C, CD80 and CD86. The volume and weight of the tumor in ADM combined with DCs vaccine group were less than those in ADM group, DCs vaccine group and control group. The tumor inhibitory rate in combination group was higher than that in the other 3 groups. Compared with the other 3 groups, the serum levels of IL-2, IL-12 and IFN-γ in combination group significantly increased. CONCLUSION：ADM combined with tumor antigen-sensitized DCs vaccine can strengthen the animal antitumor immune response and effectively inhibit the growth of tumor in cervical tumor-bearing mice.     

Alteration of the CpG ODN core sequence influences its biological functions

AIM: To investigate whether alteration of the core sequence of CpG ODN change its cellular interanalization and immunological activity. METHODS: 6-FAM labeled CpG ODN was artificial synthesized and the CpG dinucleotide was altered by cytosine methylation (mCpG ODN) and/or CG sequence reversal (GpC ODN). RAW264.7 cells were cultured in vitro. After stimulated with different 6-FAM labeled ODN, the accumulation of ODN in the cells were measured by flow cytometry. RAW264.7 cells grown on glass coverslips were pretreated with each ODN and subsequently the localization of ODN in cells were observed by confocal scanning microscopy. Meanwhile, the level of TNF-α in supernatant was tested by ELISA. RESULTS: The alteration of the core sequence of CpG ODN didnt influence its accumulation in RAW264.7 cells. In vitro, 6-FAM labeled ODN was internalized into RAW264.7 cells and a few green fluorescent dots were widely distributed over cytoplasm. Large amount of TNF-α were released from RAW264.7 cells stimulated by CpG ODN. However, after methylation of cytosine in CpG dinucleotide, the TNF-α release was significantly decreased (P<0.01). At the same time, CG sequence reversal of CpG dinucleotide completely abolished the stimulated activity of CpG ODN. CONCLUSION: Its essential for the biological function of CpG ODN with certain CG sequence. The methylation of cytosine in CpG dinucleotide doesnt influence the internalization and localization of CpG ODN in RAW264.7 cells, but partially inhibit its immunological activity.     

Role of TRAF6 in maturation of human PBMC-derived dendritic cells

AIM: To investigate the immunological effect of tumor necrosis factor receptor-associated factor 6 (TRAF6) on the maturation of dendritic cells in vitro.METHODS: The human peripheral blood mononuclear cell (PBMC)-derived dendritic cells (DCs), induced by recombined human granulocyte macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-4, were stimulated to mature with TNF-α, LPS or cocktail of cytokines (TNF-α, IL-6, IL-1β and PGE₂).The cell surface markers, T-cell stimulatory proliferation capacity and IL-12 p40 production of the DCs were determined by the methods of flow cytometry, ELISA and mixed lymphocyte reation (MLR), respectively.The mRNA expression of TRAF6 was detected by real-time PCR.RESULTS: The expression of TRAF6 was observed in all groups, which in cocktail group was the highest in the DCs with optimum state of maturation.Furthermore, TRAF6 enhanced the production of IL-12 and the ability of T-cell stimulation of mature DCs.CONCLUSION: TRAF6 might play an important role in inducing the maturation of human PBMC-derived DCs.     

Anticancer effect of mouse marrow-derived dendritic cells transfected by pcDNA3-hCEA

AIM: To prepare the vaccine of DCs(pcDNA3-hCEA) and observ the immunity effect of the DCs(pcDNA3-hCEA) inoculating on CT26(hCEA⁺) loaded in BALB/c mice. METHODS: DCs were generated from bone marrow in the presence of rmGM-CSF and rmIL-4. A new recombinant plasmid, pcDNA3-hCEA, reformed with inserting a 2.4 kb human CEA cDNA into pcDNA3. DC vaccine was prepared by transfection with pcDNA3-hCEA using lipofectamine. CEA mRNA expressed in DCs(pcDNA3-hCEA) was confirmed by RT-PCR, CEA expression level was detected with RIA method, and CEA specific CTL was induced in vitro. After vaccination of DCs(pcDNA3-hCEA), the survival time of the BALB/c mice challenged with critical loading CT26(hCEA⁺) was observed. RESULTS: G₄₁₈ test showed that about14% DCs were transfected with pcDNA3-hCEA. And CEA mRNA and protein could be detected respectively by RT-PCR and RIA in the genetically modified DCs. Furthermore, the DCs coud be targeted by specific CTL, the survival time of the mice challenged with CT26(hCEA⁺) was prolonged1-4 weeks. CONCLUSION: These results demonstrate that specific antitumor immune responses could be induced efficiently by vaccination of DCs(pcDNA3-hCEA), which is transfected eukaryotic expression vector encoding tumor antigen gene.     

Renal tumor cell lysate antigen induces the activation of dendritic cells

AIM:To investigate the effects of renal tumor cell lysates and other cytokines on the activation of immature dendritic cells (iDCs), and to develop DCs vaccines for stimulation of renal tumour-specific immunity.METHODS:DCs induced from peripheral blood mononuclear cells of healthy volunteers were cultured and propagated in vitro using rhGM-CSF and rhIL-4, and then were cocultured with renal tumor cell lysates and different cytokines. A group: only with renal tumor cell lysates; B group: with renal tumor cell lysates and TNF-α; C group: with renal tumor cell lysates and IL-1β; D group: renal tumor cell lysates and TNF-α+IL-1β. RESULTS:iDCs were induced to mature in all four groups, and high level expressions of CD86, CD80 and HLA-DR were observed. Compared to other groups, DCs in D group expressed CD83 and CD54 at higher level (P<0.05), secreted higher quantity of IL-12 (P<0.01). Moreover, mDCs in D group induced multiplication of lymphopoiesis more effectively (P<0.05).CONCLUSION:Renal tumor cell lysates and TNF-α+IL-1β induce the mature phenotype and IL-12 production in DCs and synergistically promote the stimulatory effects of lymphopoiesis.     

Role of dendritic cells in myocardial infarction and cardiac remodeling

Myocardial infarction （MI） is one of the leading causes of death worldwide. One of the primary reasons is that the rupture of atherosclerotic plaque leads to the formation of thrombosis, and then interrupts the coronary blood flow, thus finally causing the death of myocardial cells and cardiac dysfunction. A large number of researches have revealed that dendritic cells （DCs） play an essential role in immune inflammatory responses in the occurrence and development of atherosclerosis and MI. This article reviews the role of DCs in atherosclerosis, myocardial ischemia/reperfusion injury and cardiac remodeling after MI, and shows the potential values of DCs as an immunotherapeutic strategy for MI.     

Antigen-loaded dendritic cells and CD40L triggers the killing effects of cytotoxic T lymphocytes on K562 cells in vitro

AIM:To investigate the anti-tumor effects of special cytotoxic T lymphocytes (CTLs) activated by dendritic cells (DCs) loaded with antigens and CD40L in vitro.METHODS:Peripheral blood mononuclear cells were isolated by Ficoll density gradient centrifugation from normal human heparinized blood.The adherent cells were cultured with granulocyte-macrophage colony stimulating factor (GM-CSF),interleukin-4 (IL-4),alpha tumor necrosis factor (TNF-α),DCs were co-cultured with frozen-thawed antigen of K562 cells and CD40L,then triggered T cells into specific CTLs.RESULTS:Most suspended cells exhibited distinctive morphological features of DCs which expressed CD40 96%,CD86 97%,CD80 77%,CD1a 69%,and gained the powerful capacity to stimulate proliferation of allogenic lymphocytes.Under the effector∶target ratio of 20∶1,CTLs derived from cultures with DCs and frozen-thawed antigen of K562 cells were showed 71.3% cytotoxicities against K562 cells.CTLs derived from cultures with DCs loaded with frozen-thawed antigen and CD40L were showed 86.9% cytotoxicities against K562 cells.Cytotoxicities by CTLs derived from cultures with unloaded DCs against K562 cells were 37.6% and cytotoxicities by monocytes were 21.1%.Cytotoxicities by CTLs derived from experiment groups were stronger than control groups (P<0.05).CONCLUSIONS:The tumor antigen-pulsed DCs induces efficient and specific anti-tumor immunity,CTLs derived from cultures containing DCs pulsed with CD40L show the strongest cytolytic activities on K562 cells.