Analysis of the T-cell receptor (TCR) repertoire of innate CD4+ T cells selected by major histocompatibility complex (MHC) class II-dependent thymocyte-thymocyte (T-T) interaction (T-T CD4+ T cells) is essential for predicting the characteristics of the antigens that bind to these T cells and for distinguishing T-T CD4+ T cells from other types of innate T cells. Using the TCRmini Tg mouse model, we show that the repertoire of TCRalpha chains in T-T CD4+ T cells was extremely diverse, in contrast to the repertoires previously described for other types of innate T cells. The TCRalpha chain sequences significantly overlapped between T-T CD4+ T cells and conventional CD4+ T cells in the thymus and spleen. However, the diversity of the TCRalpha repertoire of T-T CD4+ T cells seemed to be restricted compared with that of conventional CD4+ T cells. Interestingly, the frequency of the parental OT-II TCRalpha chains was significantly reduced in the process of T-T interaction. This diverse and shifted repertoire in T-T CD4+ T cells has biological relevance in terms of defense against diverse pathogens and a possible regulatory role during peripheral T-T interaction.
Amino Acid Sequence ; Animals ; Antigens, Surface/metabolism ; CD4-Positive T-Lymphocytes/cytology/*immunology/*metabolism ; Cell Communication ; Cell Differentiation/genetics/immunology ; Clonal Evolution ; Histocompatibility Antigens Class II/*immunology ; *Immunity, Innate ; Immunophenotyping ; Lymphocyte Count ; Mice ; Mice, Knockout ; Mice, Transgenic ; Peptide Fragments/chemistry ; Phenotype ; Receptors, Antigen, T-Cell/chemistry/*genetics/metabolism ; Receptors, Antigen, T-Cell, alpha-beta/chemistry/genetics ; Spleen/cytology ; Thymocytes/cytology/immunology/metabolism

OBJECTIVETo study the ex vivo effect of sirolimus on capacity of splenic dendritic cells (DC) from traumatized mice in inducing T cell responses.

METHODSTwenty-four BALB/c mice were divided into control group and trauma group according to the random number table, with 12 mice in each group. Mice in trauma group were bled followed by closed femur fracture after anaesthesia, while mice in control group were only anaesthetized without injury. Twenty-four hours later DC were isolated from spleens and divided into 4 subgroups: sirolimus devoid control (trauma) groups [consisted of cells from control (trauma) groups, without sirolimus treatment] and sirolimus treated control (trauma) groups [consisted of cells from control (trauma) groups, treated with 10 microg/L sirolimus for 6 hours]. Then their autophagic activity, DC-induced mixed lymphocyte reaction (MLR) were measured and recorded as fluorescence intensity (FI) value and absorbance value respectively. The expression of major histocompatibility complex class (MHC) II and costimulatory molecules CD40, CD80, and CD86 on DC surface were measured with flow cytometry. IL-12p40, IL-12p70 and IL-10 levels in lipopolysaccharide-stimulated DC supernatants were determined by ELISA. Data were processed with one-way analysis of variance.

RESULTS(1) Compared with those of sirolimus devoid control group (FI value = 22 +/- 6), DC autophagic activity (FI value = 13 +/- 2) and DC-induced MLR in mice from sirolimus devoid trauma group were significantly weakened (F = 212.836, P < 0.05). Compared with those of sirolimus devoid control (trauma) groups, DC autophagic activity in mice from sirolimus treated control (trauma) groups (FI = 45 +/- 8, 44 +/- 8 respectively) were significantly strengthened (F = 212.836, P < 0.05 or P < 0.01). MLR in mice from sirolimus treated trauma group was stronger than that from sirolimus devoid trauma group (with F value respectively 101.426, 86.533, P values all below 0.05). (2) Compared with those of sirolimus devoid control group [MHC II (85 +/- 6)%, CD40 (8 +/- 1)%], the expressions of MHCII [(60 +/- 9)%] and CD40 [(4 +/- 1)%] on DC surface from sirolimus devoid trauma group were significantly reduced (with F value respectively 37.918, 40.426, P values all below 0.05). The expression of MHCII from sirolimus treated trauma group [(78 +/- 7)%] was higher than that from sirolimus devoid trauma group (F = 37.918, P < 0.05). (3) IL-12p40, IL-12p70 secretion by DC from sirolimus devoid trauma group [(120 +/- 13), (10 +/- 3) pg/mL] were significantly reduced as compared with those from sirolimus devoid control group [(200 +/- 25), (20 +/- 6) pg/mL, with F value respectively 218.646, 310.253, P values all below 0.05]. Compared with those from sirolimus devoid control (trauma) groups, IL-12p40 [(560 +/- 34), (540 +/- 29) pg/mL], IL-12p70 [(55 +/- 8), (60 +/- 11) pg/mL] secretion by DC from sirolimus treated control (trauma) groups were obviously enhanced (with F value respectively 218.646, 310.253, P values all below 0.01), while IL-10 secretion levels were significantly decreased (F = 246.108, P < 0.01).

CONCLUSIONSSirolimus can partially ameliorate DC functions ex vivo in traumatized mice, and further enhance the capacity of DC in inducing T cell responses.

Animals ; B7-1 Antigen ; metabolism ; B7-2 Antigen ; metabolism ; CD40 Antigens ; metabolism ; Dendritic Cells ; drug effects ; immunology ; metabolism ; Histocompatibility Antigens Class II ; immunology ; Interleukin-12 Subunit p40 ; metabolism ; Lymphocyte Culture Test, Mixed ; Male ; Mice ; Mice, Inbred BALB C ; Sirolimus ; pharmacology ; Spleen ; cytology ; immunology ; T-Lymphocytes ; immunology ; Wounds and Injuries ; immunology

BACKGROUNDGenetic modification of dendritic cells (DCs) has been used as an effective approach to enhance anti-tumor immunity. RNA interference (RNAi), which can cause the degradation of any RNA in a sequence-specific manner, is a post-transcriptional gene silencing mechanism. In this study, small-interfering RNA (siRNA) specific for the Ii gene was transfected into DCs, and the anti-tumor immunity of Ii-silenced DCs was assessed.

METHODSThe silencing effect of siRNA was evaluated by Western blotting and real-time PCR analyses. In vitro cytotoxic activity of T cells was evaluated using a Cytotox 96(®) non-radioactive cytotoxicity assay kit. The time to tumor onset and the tumor volumes were used as reliable indices to assess the anti-tumor immunity in vivo. To further examine the mechanisms underlying the anti-tumor immunity, flow cytometry analysis was used.

RESULTSThe Ii expression of DCs was significantly reduced after Ii siRNA transfection. Significant in vitro anti-tumor ability was exhibited when DCs were co-transfected with Ii siRNA plus endogenous tumor antigen (P < 0.05). Furthermore, tumor growth was greatly inhibited when mice were immunized with DCs transfected with Ii siRNA plus tumor antigen prior to or subsequent to tumor implantation. Flow cytometry analysis in vitro and in vivo indicated that both CD4(+) and CD8(+) T cells were significantly activated in the Ii siRNA group (P < 0.05).

CONCLUSIONSilencing of the Ii gene of DCs may offer a potential approach to enhance DC-based anti-tumor immunity.

Animals ; Antigens, Differentiation, B-Lymphocyte ; genetics ; metabolism ; Blotting, Western ; Cells, Cultured ; Dendritic Cells ; immunology ; metabolism ; Female ; Flow Cytometry ; Gene Silencing ; physiology ; Histocompatibility Antigens Class II ; genetics ; metabolism ; Mice ; Neoplasms ; immunology ; RNA Interference ; physiology ; RNA, Small Interfering ; genetics ; physiology ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo investigate if granulocyte-macrophage colony stimulating factor (GM-CSF) gene-modified dendritic cells (DC) enhance antitumor immunity in vitro.

METHODSMice were injected with chemokine ligand 3 (CCL3) via the tail vein. Fresh B220(-)CD11c(+) cells were sorted from the peripheral blood mononuclear cells (PBMCs) and cultured into DCs by cytokines.DCs were transfected with AdGM-CSF gene at different ratios of multiplicity of infection (MOI) to determine the optimal gene transfection conditions, and the expression of GM-CSF was detected after transfection. The variation of GM-CSF gene-modifiedDCs were analyzed by morphological examination, phenotype analysis, and mixed lymphocyte reaction (MLR).DCs were loaded with gastric cancer antigen obtained by freezing and thawing method. The killing effect of DCs vaccine-stimulated T lymphocytes on gastric cancer cells was assessed by MTT assay. INF-gamma production was determined with the INF-gamma ELISA kit.

RESULTSB220(-)CD11c(+) cells increased obviously after CCL3 injection. The ELISA results showed that after GM-CSF gene modification, DCs could produce high level of GM-CSF. When DCs were transfected with AdGM-CSF gene at MOI equal to 100, the GM-CSF level in culture supernatants reached saturation [(130.00 +/- 12.61) pg/ml]. After GM-CSF gene-modification, DCs tend to be more maturated as detected by morphological observation and phenotype analysis. At the same time, the capacity of activating the proliferation of allogeneic T lymphocytes was enhanced greatly. T lymphocytes stimulated by DCs transfected with GM-CSF gene showed a specific killing effect on gastric carcinoma cells and produced high level of INF-gamma [(1245.00 +/- 13.75) pg/ml].

CONCLUSIONAfter GM-CSF gene modification, DCs can produce high level of GM-CSF, which tend to be more maturated, and the capacity of activating the proliferation of allogeneic T lymphocytes is enhanced greatly. GM-CSF gene modified DCs can induce specific CTL to target tumor cells in vitro.

Adenoviridae ; genetics ; Animals ; B7-1 Antigen ; metabolism ; B7-2 Antigen ; metabolism ; CD40 Antigens ; metabolism ; Cancer Vaccines ; immunology ; Cell Line, Tumor ; Cell Proliferation ; Cytotoxicity, Immunologic ; Dendritic Cells ; cytology ; immunology ; metabolism ; Female ; Granulocyte-Macrophage Colony-Stimulating Factor ; genetics ; metabolism ; Histocompatibility Antigens Class II ; metabolism ; Interferon-gamma ; secretion ; Mice ; Mice, Inbred BALB C ; Recombinant Proteins ; Stomach Neoplasms ; immunology ; metabolism ; pathology ; T-Lymphocytes, Cytotoxic ; cytology ; immunology ; Transfection

Animals ; Antigens, Differentiation, B-Lymphocyte ; immunology ; Gene Expression ; Hepacivirus ; immunology ; Histocompatibility Antigens Class II ; immunology ; Mice ; Mice, Inbred BALB C ; Th1 Cells ; immunology ; metabolism ; Viral Hepatitis Vaccines ; genetics ; immunology

OBJECTIVETo investigate whether there is an association between the expression of B7-H1 in HBV transgenic mice and the immune tolerance to HBV.

METHODST cells stimulatory capacity of DC was analyzed using mixed lymphocyte reaction. Expression of MHC-II, CD80, CD86, B7-H1 on DC was detected by Flow Cytometry. IL-2, IFNgamma, IL-10 production of T cells were determined by using ELISA. B7-H1 mRNA and protein expression in liver tissue were detected by RT-PCR and Western blotting respectively.

RESULTSThe ability of DC cells from HBV transgenic mice to stimulate T cell proliferation was significantly impaired compared with DC cells from control mice (t = 16.674, 19.674, 21.712, P less than 0.01). Expression of MHC-II, CD80 on DC was markedly decreased in transgenic mice (t = 7.910, 6.413, P less than 0.05). Meanwhile, the expression of CD86 and B7-H1 on DC cells in HBV transgenic mice were not significantly different from that in control mice. The levels of IL-2, IFNgamma, IL-10 in supernatant of T cells was significantly lower compared with controls (t = 18.712, 18.712 and 11.683, P less than 0.05). There was no significant difference in B7-H1 expression at mRNA and protein levels in liver tissue compared with controls.

CONCLUSIONSFunctional defect of DC, partly due to decreased expression of MHC-II, CD80, but not related to B7-H1 expression, is the cause for immune tolerance to HBV in HBV transgenic mice.

Animals ; Antigens, CD ; biosynthesis ; genetics ; Cell Proliferation ; Cytokines ; biosynthesis ; Dendritic Cells ; immunology ; metabolism ; Flow Cytometry ; Hepatitis B virus ; genetics ; immunology ; Histocompatibility Antigens Class II ; metabolism ; Immune Tolerance ; Liver ; metabolism ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Mice, Transgenic ; RNA, Messenger ; genetics ; metabolism ; Spleen ; immunology ; metabolism ; T-Lymphocytes ; immunology ; metabolism

Legionella bacterium, an intracellular pathogen of mononuclear phagocytes, causes acute fatal pneumonia, especially in patients with impaired cellular immune responses. Until recently, however, the toll-like receptor (TLR) engagement of bacterial proteins derived from Legionella is uncertain. We previously showed that a 19-kDa highly conserved peptidoglycan-associated lipoprotein (PAL) of Legionella pneumophila induced the PAL-specific B cell and T cell responses in mice. In this study, we observed that the rPAL antigen of L. pneumophila, as an effector molecule, activated murine macrophages via TLR2 and produced proinflammatory cytokines such as IL-6 and TNF-alpha. In both BALB/c and TLR4-deficient C3H/HeJ mice, pretreatment of macrophages with anti-TLR2 mAb showed severely impaired cytokine production in response to the rPAL. In addition, in vitro the rPAL treatment increased the cell surface expression of CD40, CD80, CD86 and MHC I/II molecules. We further showed that the synthetic CpG-oligodeoxynucleotides (CpG ODN) coadministered with the rPAL enhanced IL-12 and IL-6 production and expression of CD40, CD80 and MHC II compared to the rPAL treatment alone. In conclusions, these results indicate that Legionella PAL might activate macrophages via a TLR2-dependent mechanism which thus induce cytokine production and expression of costimulatory and MHC molecules.
Animals ; Antigens, CD/immunology/metabolism ; Bacterial Outer Membrane Proteins/*pharmacology ; Cells, Cultured ; Female ; Histocompatibility Antigens Class II/immunology/metabolism ; Host-Pathogen Interactions ; Interleukin-12/biosynthesis ; Interleukin-6/biosynthesis ; Legionella pneumophila/*immunology/metabolism ; Legionnaires' Disease/immunology/metabolism ; Lipoproteins/*pharmacology ; Macrophage Activation/drug effects/immunology ; Macrophages, Peritoneal/drug effects/immunology/*metabolism ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C3H ; Mice, Inbred C57BL ; Toll-Like Receptor 2/*metabolism ; Tumor Necrosis Factor-alpha/biosynthesis

OBJECTIVETo investigate the influence of glucocorticoid on phenotype of thymic dendritic cells in mice and to investigate the protective effect of Yougui Pill (YGP) on it.

METHODSBALB/c mice allocated in the group A and B were treated respectively with 10 mg/kg hydrocortisone, alone and combined with 20.81 g/kg YGP. The control mice were treated with normal saline. The changes before and after treatment of I-A(d) and H-2K(d) antigen presentation molecules expression in CD11c(+) and CD45(+) thymic dendritic cells of mice were analyzed by flow cytometry assay, and the expression of intercellular adhesion molecule-1 (ICAM-1) and leukocyte function-associated antigen-1 (LFA-1) mRNA in thymocytes were determined by RT-PCR as well.

RESULTSThe percentage of I-A(d+) and H-2K(d+) in CD11c(+) in Group A after treatment was 46.77 +/- 4.32% and 64.34 +/- 7.69% respectively, as compared with those in the control group (65.81 +/- 7.69% and 31.88 +/- 5.01%), the percentage of I-A(d+) was lower and that of H-2K(d+) was higher significantly (all P <0.01). Meantime, the expression of ICAM-1 and LFA-1 in thymocyte in Group A (30.11 +/- 2.51% and 30.40 +/- 3.77%) was significantly lower than that in the control group (46.35 +/- 3.34% and 47.28 +/- 2.91%) respectively (P <0.01). Changes in Group B showed that treated by hydrocortisone in combination with YGP, the above-mentioned hydrocortisone-induced changes could be obviously reversed, the outcome of CD11c(+) I-A(d+) was 54.19 +/- 5.08%, ICAM-1 33.97 +/- 2.04% and LFA-1 34.80 +/- 2.92%, the difference between the two treated groups in these indexes all showed statistical significance (P <0.05).

CONCLUSIONGlucocorticoidcan inhibit the expression of major histocompatibility complex class II antigen molecule, but promote the expression of major histocompatibility complex class I in CD11c(+) and CD45(+) dendritic cells, down-regulate ICAM-1 and LFA-1 transcription, while the tonifying yang recipe, YGP, has a dominant protective effect against the above actions of glucocorticoid.

Animals ; CD11c Antigen ; metabolism ; Dendritic Cells ; cytology ; drug effects ; immunology ; Drugs, Chinese Herbal ; pharmacology ; H-2 Antigens ; metabolism ; Histocompatibility Antigens Class II ; metabolism ; Hydrocortisone ; toxicity ; Intercellular Adhesion Molecule-1 ; metabolism ; Leukocyte Common Antigens ; metabolism ; Lymphocyte Function-Associated Antigen-1 ; metabolism ; Mice ; Mice, Inbred BALB C ; Phenotype ; Protective Agents ; pharmacology ; Thymus Gland ; cytology ; drug effects ; immunology

OBJECTIVETo construct a dendritic cell vaccine transduced by murine alpha-fetoprotein (mAFP) gene, and evaluate its immunoprotective effect on C57BL/6J mice during the induction of hepatocellular carcinoma by diethylnitrosamines, carbon tetrachloride and ethanol.

METHODSDendritic cells (DCs) were induced and augmented by murine IL-4 and GM-CSF, and transfected by recombinant adenovirus engineered with mAFP gene. Major MHC class I and II, B7.1 (CD80), B7.2 (CD86), CD18a, and CD54 molecules on DC were analyzed by FACS. 80 C57BL/6J male mice were randomly divided into 4 groups (20 mice per group): Simple DC inoculated group, pAdBM5-mAFP-DC inoculated group, pAdBM5-mAFP plasmid inoculated group, and PBS control group. They were immunized once with 5 x 10(5) DCs (0.1 ml)/mouse administered s. c. in the left flank or 100 mg pAdBMS-mAFP plasmid/mouse administered i. m. in the left tibialis anterior muscle. Inoculation was conducted once a week for 4 weeks after 3 times consecutive immunization initially. At the same time of immunization, DEN/CCl4/ethanol were given to induce hepatocellular carcinoma. Tumor incidence was assessed after 20 weeks.

RESULTSA transgenic DC vaccine was successfully constructed and the mAFP transgenic DCs expressed high level molecules of major MHC class I and II , B7.1, B7.2, CD18a, and CD54. After the 20-week induction, the incidence of primary hepatocellular carcinoma (PLC) was 70.0% in simple DC inoculated group, 25.0% in pAdBMS-mAFP-DC inoculated group, 65.0% in pAdBM5-mAFP plasmid inoculated group, and 75.0% in PBS control group. There was a significant difference between group B and other groups (P < 0.05).

CONCLUSIONmAFP transgenic DC tumor vaccine inoculation may induce strong immunoprotection against liver carcinogenesis and tumor development and reduce PLC incidence induced by DEN/CCl4/ethanol.

Adenoviridae ; genetics ; Animals ; B7-1 Antigen ; metabolism ; Cancer Vaccines ; Carbon Tetrachloride ; Cells, Cultured ; Dendritic Cells ; cytology ; immunology ; metabolism ; Diethylnitrosamine ; Ethanol ; Genetic Vectors ; Histocompatibility Antigens Class I ; metabolism ; Histocompatibility Antigens Class II ; metabolism ; Intercellular Adhesion Molecule-1 ; metabolism ; Liver Neoplasms, Experimental ; chemically induced ; immunology ; prevention & control ; Male ; Mice ; Mice, Inbred C57BL ; Random Allocation ; Recombinant Proteins ; genetics ; metabolism ; Transfection ; alpha-Fetoproteins ; genetics ; metabolism

OBJECTIVETo separate and identify the exosomes derived from a mouse hepatoma carcinoma cell line (H22) and to detect their protein composition, and to investigate the possibility of using these exosomes as a kind of tumor vaccine.

METHODSExosomes were purified by serial ultracentrifugation and sugar density ultracentrifugation, and then they were observed and identified by electron microscopy. Exosomes underwent peptide mass fingerprint and Western blot analyses.

RESULTSH22 cell-derived exosomes were 20-90 nm round or oval vesicles. The exosomes expressed HSP70, ICAM-1, EF-G2, DLC-A, C-myc protein and Vav-2 protein.

CONCLUSIONSerial ultracentrifugation and sugar density ultracentrifugation can be used to purify H22 cell-derived exosomes. H22 cell-derived exosomes express a distinct set of proteins involving in and/or relating to antigen presentation (HSP70, ICAM-1), migration (DLC-A), adhesion (ICAM-1), cytoskeleton (EF-G2) and tumour antigens (C-myc, Vav-2). The exosomes have immunogenicity.

Animals ; Carcinoma, Hepatocellular ; immunology ; metabolism ; Cell Line, Tumor ; Exosomes ; immunology ; secretion ; Histocompatibility Antigens Class II ; immunology ; Liver Neoplasms ; immunology ; metabolism ; Mice ; Peptide Mapping