This study was aimed to investigate the effects of tumor antigen-loaded dendritic cells (DC) stimulating the specific cytotoxic T lymphocytes (CTL) on Jurkat cells in vitro. Peripheral blood mononuclear cells were isolated by Ficoll density gradient centrifugation from normal human heparinized blood, the adherent monocytes were cultured with granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin-4 (IL-4), alpha tumor necrosis factor (TNF-alpha) and sCD40L, DCs were co-cultured with frozen-thawed antigen of Jurkat cells or WT1 peptides, and then T cells were triggered into specific CTL. The results showed that most suspended cells exhibited distinctive morphological features of DC which expressed CD40 (96%), CD86 (97%), CD80 (77%), CD1a (69%), and gained the powerful capacity to stimulate proliferation of allogeneic lymphocytes. Under the effector: target ratio of 20:1, CTLs derived from cultures with DC and frozen-thawed antigen of Jurkat cells showed 91.1% cytotoxicity against Jurkat cells, CTL derived from cultures with DC and WT1 peptides showed 87.5% cytotoxicity against Jurkat cells, cytotoxicity of CTL derived from cultures with unloaded DC against Jurkat cells was 42.1% and cytotoxicity of monocytes was 22.7%. Cytotoxicity of CTL derived from culture with frozen-thawed antigen or WT1 peptides loaded DC was stronger than that in control groups (P < 0.01). It is concluded that the tumor antigen-pulsed DC can induce efficient and specific anti-tumor immunity, may play a great role in clinical therapy for leukemia.
Antigens, Neoplasm ; immunology ; Cells, Cultured ; Coculture Techniques ; Dendritic Cells ; cytology ; immunology ; Humans ; Jurkat Cells ; Leukemia, T-Cell ; immunology ; pathology ; Lymphocyte Activation ; T-Lymphocytes, Cytotoxic ; immunology ; Tumor Cells, Cultured

OBJECTIVETo study the immune responses of lymphocytes after activated by dendritic cells (DCs) loaded with cytotoxicity T lymphocyte (CTL) epitope based peptide of human alpha-fetoprotein (hAFP, 218-226 LLNQHACAV).

METHODSGet high purity DCs by cultured plastic-adherent monocytes isolated from healthy donor of HLA-A2(+) peripheral blood with granulocyte-monocyte colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) for 7 days. Stimulate self-lymphocytes with DCs that loaded with CTL epitope based peptide of hAFP under the culture medium contains interleukin-2 (IL-2) for 7 days. Analyse IL-12 and TNF in culture medium and also the specific lysis activity of lymphocytes against four strains of primary hepatocellular carcinoma cells.

RESULTSAfter stimulated by DC loaded with CTL epitope based peptide derived from hAFP, lymphocytes appeared a good characteristics and the culture medium of activated lymphocytes contained a high level Th1 type cytokines of IL-12 and TNF. Activated lymphocytes not only specifically lysed HLA-A2(+) HepG2 line but also had the cytotoxicity against other three primary hepatocellular carcinoma cell lines and T2 target cell loaded with peptide of hAFP.

CONCLUSIONSThe results of this research supply the basic materials for the DC based vaccine with HLA-A2 restricted peptide epitope derived from hAFP against AFP positive primary hepatocellular carcinoma.

Adult ; Animals ; Dendritic Cells ; immunology ; Epitopes ; HLA-A2 Antigen ; immunology ; Humans ; K562 Cells ; Mice ; Peptides ; immunology ; T-Lymphocytes, Cytotoxic ; immunology ; Tumor Cells, Cultured ; alpha-Fetoproteins ; immunology

After having successfully constructed and expressed the gene of the anti-CD3/anti-CD20 bispecific single-chain antibody (bscCD3 x CD20), here we analyzed its in vitro bioactivity of mediating the lysis of Ramous human B-lymphoma cells in the presence of T-enriched human peripheral blood lymphocytes (PBL). Obvious opoptosis characters were observed by Annexin V/PI(AV/PI) stained and scanning electron microscope. As evaluated by non-radioactive cytotoxity assay, the bscCD3 x CD20 showed potent bioactivity of mediating human B-lymphoma cells lysis in the presence of T-enriched human PBL. The potency of cytotoxicity depended on the ratios of effect cells to target cells (E:T) used. Further, the antibody showed a dose and time-dependent effect on mediating Ramous cells lysis. The specific lysis reached about 87.3% at an antibody concentration of 5microg/mL and E:T used at 10:1. Clear changes in apoptogenes expression profiles were detected by apoptosis gene array after Ramous cells were treated with the antibody and PBL. Among the upregulated apoptogenes, ATM and P53 showed an increase of 187 times and 15 times respectively, which suggested that ATM-p53 pathway may be the main apoptosis way of Ramous cells induced by T cells in the presence of the bscCD3 x CD20.
Antibodies, Bispecific ; immunology ; Antigens, CD20 ; immunology ; Apoptosis ; immunology ; CD3 Complex ; immunology ; Humans ; Lymphoma, B-Cell ; immunology ; pathology ; T-Lymphocytes, Cytotoxic ; immunology ; Tumor Cells, Cultured

OBJECTIVETo establish a method for efficient induction and expansion of Epstein Barr virus (EBV)-specific cytotoxic T lymphocytes (CTL) in vitro and evaluate the possibility of using this strategy for treatment of nasopharyngeal carcinoma (NPC).

METHODSEBV-transformed B lymphoblastoid cells (BLCLs) were used as the antigen stimuli and antigen-presenting cells. EBV-specific CTL was induced by co-culture of the autologous peripheral blood mononuclear cells (PBMCs) and the irradiated BLCLs, and expanded with a cocktail method consisting of OKT-3, irradiated homologous PBMC, and IL-2. The specific activity of the CTL against the NPC cells was measured with MTT assay.

RESULTSEBV-specific CTL was successfully induced and expanded by 600 folds. The killing efficiency of the CTL was 76% for autologous BLCLs, 13% for homologous BLCLs, 51% for autologous NPC cells, and 27% for homologous CNE cell line, and after expansion, the corresponding killing efficiencies were 63%, 25%, 49%, and 33%, respectively. The non-specific killing only slightly increased after the expansion.

CONCLUSIONEBV-specific CTL can be successfully induced and expanded in vitro for specific killing of autologous NPC cells, suggesting the potential of this strategy in the treatment of NPC.

Antigen-Presenting Cells ; cytology ; immunology ; Antigens, Viral ; immunology ; B-Lymphocytes ; cytology ; immunology ; virology ; Cells, Cultured ; Coculture Techniques ; Herpesvirus 4, Human ; immunology ; Humans ; Immunotherapy, Adoptive ; Nasopharyngeal Neoplasms ; immunology ; pathology ; therapy ; T-Lymphocytes, Cytotoxic ; cytology ; immunology ; virology ; Tumor Cells, Cultured

In order to investigate the inhibition role of anti-Fas hammerhead ribozyme on Fas expression and Fas-mediated apoptosis in CTLL-2 cells (mouse CTL cell line), and to explore a new way for enhancing the ability of T cells against Leukemia in donor lymphocytes infusion, CTLL-2 cells were transfected with pEGFP-RZ596 and pEGFPC1 (mock-transfected) via electroporation. Fas expression on CTLL-2 cells was detected by RT-PCR and Western blot. The killing effect of CTL against WEHI-3 (mouse acute myelomonocytic leukemia cell line) highly expressing FasL in vitro was detected by MTT assay. The caspase-3 proteolytic activity and the apoptosis rate of CTLL-2 cells were detected by means of BD AproAlert Caspase-3 Colorimetric kit and FITC labeled Annexin-V apoptosis detecting kit respectively. The results showed that the anti-Fas ribozyme could be successfully introduced into mouse CTLL-2 cells; Fas expression on the surface of cells transfected with the ribozyme was obviously decreased, in comparison with control and mock-transfected cells; after cocultured with WEHI-3 cells, the viability of CTLL-2 cells transfeced with the ribozyme was significantly increased, as compared with other two groups; caspase-3 activity and apoptosis rate of the ribozyme-transfeced cells were significantly decreased, the killing effect of CTLL-2 transfected with the ribozyme was stronger than that of other groups. It is concluded that anti-Fas ribozyme can remarkably decrease Fas expression on CTLL-2 cells, so as to avoid Fas-mediated apoptosis by Fas ligand on WEHI-3 cells, and to enhance their killing activity against WEHI-3 cells, as a result, the immune escape of acute myelomonocytic leukemia was depressed.
Animals ; Cell Line ; Fas Ligand Protein ; immunology ; Leukemia, Myelomonocytic, Acute ; immunology ; Mice ; RNA, Catalytic ; T-Lymphocytes, Cytotoxic ; cytology ; immunology ; Tumor Cells, Cultured ; Tumor Escape ; genetics ; immunology

OBJECTIVESTo assess the feasibility and efficacy of eliciting leukemia-specific T-cell responses in syngeneic mice in vitro and in vivo using dendritic cells (DCs) pulsed with total RNA from leukemia cells.

METHODSDCs generated from bone marrow culture in vitro in the presence of combined cytokines were pulsed with cellular total RNA isolated from cultured L615 cells by cationic lipid 1,2-dioleoyloxy-3-(trimethylammonium) propane (DOTAP). T-cell responses were evaluated by in vitro proliferation, and cytotoxicity assay. And in vivo immune protection and prognosis of mice with leukemia were studied.

RESULTSDCs pulsed with total RNA isolated from cultured L615 cells (DCs/RNA) were remarkably effective in stimulating L615-specific T-cell response in vitro, but did not cross-react with other leukemia cells from syngeneic mice. Vaccination of naive mice with viable DCs/RNA vaccine was able to partly protect from challenge with a lethal dose of live L615 cells, leading to low leukemia incidence and overall survival prolongation. Statistically significant survival was also observed in a low lethal dose of L615-bearing mice that received treatment using viable DCs/RNA vaccine alone, suggesting that systemic administration of IL-2 could enhance the anti-tumor efficacy of leukemia RNA/DCs vaccine.

CONCLUSIONSThese data support the use of DCs/RNA vaccine as a feasible and effective route to elicit leukemia immunity against unidentified leukemia-associated antigens for treatment of leukemia-bearing animals.

Animals ; Cancer Vaccines ; Dendritic Cells ; immunology ; Leukemia, Experimental ; immunology ; Mice ; RNA, Neoplasm ; immunology ; isolation & purification ; T-Lymphocytes ; immunology ; Tumor Cells, Cultured

B7-1 Antigen ; genetics ; immunology ; Carcinoma, Hepatocellular ; genetics ; immunology ; Enterotoxins ; genetics ; immunology ; Genetic Vectors ; Humans ; Liver Neoplasms ; genetics ; immunology ; T-Lymphocytes ; immunology ; Transfection ; Tumor Cells, Cultured

OBJECTIVETo induce primary chronic myeloid leukemia (CML) cells into dendritic cells (DCs).

METHODSBone marrow mononuclear cells (MNCs) were isolated from 13 CML patients and peripheral blood MNCs from 5 healthy donors. The isolated MNCs were co-cultured with rhGM-CSF 1,000 U/ml, rhIL- 4,500 U/ml and TNF-alpha 50 U/ml for 10 days. The morphological features were observed by Wright's staining,inverted microscope and electron microscope. CD(80), CD(86), CD(83), CD(1a) and HLA-DR expression were assayed by flow cytometry, cytogenetic analysis was performed by fluorescence in-situ hybridization(FISH). The concentration of IL-12 was measured by ELISA and the function of antigen presenting was tested by mixed lymphocyte reaction (MLR).

RESULTAfter being cultured with cytokines, the typical dendritic appearance with delicate membrane projections was observed. The CD(80), CD(86), CD(83), CD(1a) and HLA-DR markers and capacity of stimulating allogeneic T cells were upregulated significantly. FISH confirmed that the DCs were generated from leukemic origin and CML DCs could secrete higher level of IL-12 than CML MNCs. There were no differences in morphology and immunophenotype expression between DCs derived from CML and those from normal individuals. However, DCs from CML patients displayed weaker activity than that of normal individuals when tested in MLR.

CONCLUSIONCML cells could be induced into leukemia-DCs by co-culture with cytokines.

Bone Marrow Cells ; immunology ; pathology ; Cell Differentiation ; Dendritic Cells ; cytology ; immunology ; Humans ; Interleukin-12 ; metabolism ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; immunology ; pathology ; Tumor Cells, Cultured

Animals ; Cancer Vaccines ; immunology ; Cell Fusion ; methods ; Cell Line ; Dendritic Cells ; cytology ; immunology ; Fibrosarcoma ; immunology ; pathology ; Hybrid Cells ; immunology ; Mastocytoma ; immunology ; pathology ; Mice ; Mice, Inbred BALB C ; T-Lymphocytes ; immunology ; pathology ; T-Lymphocytes, Cytotoxic ; immunology ; Tumor Cells, Cultured

OBJECTIVETo study the role of dendritic cells (DCs) and macrophages, differentiated from the same individual peripheral blood monocytes, in tumor antigen- presenting.

METHODSDCs and macrophages were differentiated from human peripheral blood monocytes by adding both Granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) or GM-CSF only. Then they were loaded with tumor antigen at different concentrations and cocultured with autologous T cells in 96-well flat-bottomed microtiter plates for five days at 37 degrees C, 5% CO(2). (3)H-thymine was added before the culture terminated, and twelve hours later, the cells were gathered to test the cpm value.

RESULTSBoth DCs and macrophages chased with tumor antigen could strongly stimulate the proliferation of autologous T cells, especially DCs. The stimulation effect with 20 microl/ml antigen was the most remarkable and the cmp values were 11,950.3 +/-1621.8, 8,708.5 +/-176.1, 402.5+/-43.1 in DCs group, Macrophages group, and lymphocytes group, respectively.

CONCLUSIONThe antigen presenting role of DCs is stronger than that of macrophages from the same individual.

Antigen Presentation ; immunology ; Antigen-Presenting Cells ; immunology ; physiology ; Antigens, Neoplasm ; immunology ; Carcinoma, Hepatocellular ; immunology ; Dendritic Cells ; immunology ; physiology ; Granulocyte-Macrophage Colony-Stimulating Factor ; pharmacology ; Humans ; Liver Neoplasms ; immunology ; Macrophages ; immunology ; physiology ; Tumor Cells, Cultured