OBJECTIVETo establish a method for isolating exosomes from dendritic cells (DC), and to analyse its biological characteristics and function in antitumor immunity.

METHODSImmature DCs (im-DC) from human peripheral blood mononuclear cells were loaded with the antigen of K562 tumor cells, then exosomes were secreted from imDC and lipopolysaccharide (LPS) induced mature DC (mDC). The exosomes from imDC and mDC were isolated separately by ultracentrifugation and ultrafiltration. The exosomes diameter was determined, their profile was observed by electron microscope, and the surface molecules were detected by Western blot. To analyse the effect of exosomes on antitumor immunity, the proliferation, IFN-gamma expression, CD69 up-regulation and cytotoxicity of antigen-specific T cells were measured.

RESULTSExosomes were small flattened sphere vesicles with an average diameter of 72.3 nm and expressed CD80, CD86, HLA-DR, FasL, CD54 and MFG-E8 molecules. As compared to immature exosomes, exosomes from mDC were proved to express more CD80 and less MFG-E8, to be more potent for inducing antigen-specific T cells proliferation and immunity respond in vitro: at its optimum concentration, the absorption value of T cell proliferation test was 0.50 +/- 0.01, CD69 was up-regulated and (13.4 +/- 5.8)% of T cells was in proliferating, (22.8 +/-2.4)% of T cells expressed IFN-gamma, and (21.3 +/-8.6)% of tumor cells were killed.

CONCLUSIONA simple and quick method to isolate and analyse exosomes is established. The exosomes can induce antitumor immunity respond.

Cells, Cultured ; Dendritic Cells ; immunology ; secretion ; Exosomes ; immunology ; Humans ; Lymphocyte Activation ; drug effects ; T-Lymphocytes ; drug effects ; immunology

The aim of this study was to explore the regulatory function of interleukin-6(IL-6) on human Th17 cells. Human peripheral blood CD4(+) T cells were purified from healthy donors by anti-CD4 monoclonal antibody (mAb) conjugated microbeads. The experiment was divided into 2 groups. Test group in which CD4(+) T cells (1 × 10(6)/ml) were stimulated by human recombined IL-6 (20 ng/ml) for 4 days; control group in which CD4(+) T cells did not stimulated by IL-6. The concentrations of IL-17 protein in the supernatants were assayed by enzyme-linked immunosorbent assay (ELISA), and quantity of Th17 cells were detected by flow cytometry. The results showed that as compared to control group, IL-17 protein level in the supernatants of CD4(+) T cells significantly increased in IL-6 stimulated group: (337.05 ± 189.09 pg/ml; vs 15.07 ± 12.70 pg/ml) (p < 0.05). Furthermore, the percentage of Th17 cells in cultures of CD4(+) T cells stimulated by IL-6 was significantly higher than that in control group (4.05% ± 0.30% vs. 2.81% ± 0.44%)(p < 0.01). It is concluded that IL-6 promotes the expansion of Th17 cells in vitro.
CD4-Positive T-Lymphocytes ; cytology ; immunology ; Cells, Cultured ; Humans ; Interleukin-6 ; pharmacology ; Lymphocyte Activation ; immunology ; Th17 Cells ; drug effects ; immunology

This study was purposed to investigate the effect of prostaglandin E2 (PGE2) on proliferation of peripheral blood T lymphocytes, and to evaluate the regulatory role of PGE2 on immunological balance between Th1/Th2 and Tc1/Tc2 lymphocytes. The peripheral blood mononuclear cells (PBMNC) were stimulated by anti-human CD3 monoclonal antibody (mAb) and anti-human CD28 mAb, and were cultured in the presence of different concentration of PGE2 for 120 hours. The proliferation of peripheral blood T lymphocytes was assayed according to the manufacture protocol of BrdU Kit; the IFN-gamma and IL-4 levels in supernatants cultured for 24, 48, 72 and 120 hours were detected by ELISA; the ratios of CD4+IL-4+ T cells/CD4+ IFN-gamma+ T cells and CD8+IL-4+ T cell/CD8+IFN-gamma+ T cells were determined by flow cytometry. The cells cultured without PGE2 were used as control. The results indicated that (1) with the raising of concentration of PGE2, the inhibitory rate of T cell proliferation in vitro significantly increased (p=0.001). There was significant positive correlation between inhibitory rate of T cells and PGE2 concentration (correlation coefficient=0.889, p=0.000). (2) the difference between the IFN-gamma concentrations in supernatant cultured for 120 and 72 hours in test groups had no statistical significance (p=0.917). The IFN-gamma concentration increased continually with prolonging of culture time in control group (p=0.046). The IFN-gamma concentrations produced at different times in test group were significantly lower compared with those in control group (p<0.05). The IL-4 concentrations produced at different time had no significant change in test groups (p=0.400). The IL-4 concentration in 24 hours in control group was significantly higher than that at 48, 72 and 120 hours in control group (p=0.007, 0.003 and 0.002). After cultured for 24 hours the IL-4 concentration in test group was significantly lower than that in control group (p=0.037), but after cultured for 48, 72 and 120 hours, the IL-4 concentration in test group did not show statistical difference in comparison with control group (p>0.05). (3) the proportions of CD4+IFN-gamma+T cells in test group and in control group had no significant difference (p=0.767). The proportion of CD4+IL-4+T cells in test group was slightly higher than that in control group (p=0.051). The ratio of CD4+IL-4+T cells to CD4+IFN-gamma+ T cells in test group was significantly higher than that in control group (p=0.011). The proportions of CD8+IFN-gamma+ T cells in test group and in control group had no statistical difference (p=0.441). The proportion of CD8+IL-4+T cells in test group was significantly higher than that in control group (p=0.015). The ratio of CD8+IL-4+ T cells to CD8+IFN-gamma+ T cells in test group were obviously higher than that in control group(p=0.038). It is concluded that the PGE2 inhibits the proliferation of T lymphocytes in vitro. PGE2 influences the production of IFN-gamma and IL-4, and significantly influences peak appearance of IFN-gamma produced by T lymphocyte. PGE2 can continuously inhibit the production of IFN-gamma, but its continuous effect on IL-4 is no significant. PGE2 enhances the ratio of CD4+IL-4+T lymphocytes to CD4+IFN-gamma+T lymphocytes and the ratio of CD8+IL-4+T lymphocytes to CD8+IFN-gamma+T lymphocytes, and regulates development of T cells toward Th2/Tc2 cells.
Cell Proliferation ; drug effects ; Dinoprostone ; pharmacology ; Flow Cytometry ; Humans ; Lymphocyte Activation ; drug effects ; Lymphocyte Count ; T-Lymphocytes, Cytotoxic ; drug effects ; immunology ; Th1 Cells ; drug effects ; immunology ; Th2 Cells ; drug effects ; immunology

This study was aimed to investigate the effect of dexamethasone (Dex) on immunosuppressive ability of mesenchymal stem cells (MSC) during expansion and differentiation of MSC. MSC were cultured in 96-well flat-bottom plates. Proliferation assays were performed by using the BrdU colorimetric ELISA Kit. To explore the effect of Dex on MSC immunosuppressive ability, MSC were firstly cultured in complete culture medium for 14 d with Dex (10 nmol/L), and then, peripheral blood mononuclear cells (PBMNC) were co-cultured with MSC in 96-well flat-bottom plates for 3 d. Phytohemagglutinin A (PHA, 10 µg/ml) was used to stimulate activation of PBMNC. The concentrations of IFN-γ in culture supernatants was detected by ELISA. The results indicated that there was no obvious difference in representative phenotypes of MSC between experimental and control groups after MSC were treated with low concentration of Dex (10 nmol/L) for 14 d, but the suppression of Dex-treated MSC on lymphocyte activation in same concentration of cells was significantly reduced as compared with control group. After the Dex-treated MSC were co-cultured with IFN-γ for 12 h, the immunoregulatory ability of MSC was recovered in a certain degree. It is concluded that the Dex impairs the immunosuppressive ability of MSC, the IFN-γ can protect and reverse the immunosuppressive ability of MSC impaired by Dex, so that, when the immunoregulatory activity of MSC is investigated, it is necessary to avoid adding Dex in the culture medium.
Cells, Cultured ; Dexamethasone ; adverse effects ; Humans ; Immune Tolerance ; drug effects ; Interferon-gamma ; immunology ; Leukocytes, Mononuclear ; Lymphocyte Activation ; immunology ; Mesenchymal Stromal Cells ; cytology ; drug effects ; immunology

Antigens, CD ; metabolism ; Antigens, Differentiation, T-Lymphocyte ; metabolism ; CD3 Complex ; metabolism ; Cells, Cultured ; Humans ; Kinetics ; Lectins, C-Type ; metabolism ; Lymphocyte Activation ; T-Lymphocyte Subsets ; drug effects ; immunology ; metabolism

In order to study how to activate T cells and their immunological characteristics, the anti-CD3 and anti-CD28 McAbs were used to stimulate PBMNC, then their related immunological changes, such as lymphocyte transformation function, the percentage of CD8(+)CD25(+) cells and TGF-beta expression were deleted by lymphocyte transformation assay, flow cytometry and RT-PCR respectively. The results showed that in costimulation with anti-CD28 antibody stimulation, the activity of anti-CD3 antibody was significantly enhanced, the ratio of CD8(+)CD25(+) cells of T cells was obviously increased, while TGF-beta expression was down-regulated. It was concluded that the anti-CD28 antibody costimulation could provide stimulatory signal II, which make T cells more active, while the expression of TGF-beta significantly down-regulated.
Antibodies, Monoclonal ; pharmacology ; CD28 Antigens ; immunology ; CD3 Complex ; immunology ; Down-Regulation ; Humans ; Leukocytes, Mononuclear ; immunology ; metabolism ; Lymphocyte Activation ; drug effects ; T-Lymphocytes ; immunology ; Transforming Growth Factor beta ; biosynthesis

To confirm the mechanism of exosomes as tumor vaccines inducing immunity response, dendritic cells (DCs) were induced from human peripheral blood mononuclear cells, while exosomes were isolated from DC loaded tumor antigen. The effect of exosomes on priming T cell proliferation was analysed under conditions with or without DCs, or DCs at different mature stages. The function of exosomes in immunity was detected through block test after blocking some molecules (CD11a, CD11b, CD11c, CD54, MFG-E8 and CD83). The effect of DCs on embedded exosomes was observed by confocal microscopy, the effect of blocking surface molecules on exosomes on DC-embedding exosomes was assayed by flow cytometry. The results indicated that both exosomes derived from imDC (imDex) and exosomes derived from mDC (mDex) could not prime T cells without DC or with imDC. The exosomes derived from mDC induced with different cytokines (LPS, TNF-alpha, CpG, CD40L) were no significant difference in concentrations but were different in effect. The immunity function of exosomes depended on CD11a, CD11b, CD11c, CD54, MFG-E8 and CD83 molecules, the effect of priming T cells is reduced when these molecules were blocked. Confocal microscopy and FACS assay showed that blocking CD11a and CD54 could inhibit exosome-targeted DC and DC-embedded exosomes. It is concluded that the exosomes target DCs through their surface molecules, therefore results in immune response of T cells.
Antigens, Neoplasm ; immunology ; Cells, Cultured ; Dendritic Cells ; cytology ; immunology ; secretion ; Exosomes ; immunology ; Humans ; K562 Cells ; Lymphocyte Activation ; drug effects ; T-Lymphocytes ; cytology ; immunology

BACKGROUNDThere has been increasing interest in the research into cytomegalovirus (CMV) pneumonia after liver transplantation (LT). This study was undertaken to investigate the immunomodulatory therapy of CMV pneumonia after LT.

METHODSSix patients with CMV pneumonia after LT from October 2003 to November 2005 were analyzed retrospectively. They were diagnosed according to clinical manifestations, chest X-ray findings and pathogenic changes and given comprehensive therapy including mainly immunomodulation therapy and anti-viral medication. At the early stage of CMV pneumonia, the dose of immunosuppressive agents was decreased or ceased, instead replaced by immunoenhancement therapy. During recovery period from CMV pneumonia, the dose of immunosuppressive agents was given again or enhanced, and immunoenhancement therapy was ceased. The liver function of the patients was monitored closely during the treatment.

RESULTSIn this series, five patients were survived and one died. The liver function of the six patients remained normal during the treatment, and no episode of acute rejection took place.

CONCLUSIONSPoor immunity is the pathogenic basis of CMV pneumonia after LT. At early stage of CMV pneumonia, the immunity of the patients should be enhanced, and during the recovery period from CMV pneumonia, immunosuppressants should be given again but immunoenhancement therapy ceased. Individualized immunomodulatory therapy is essential to the treatment of CMV pneumonia after LT.

Adjuvants, Immunologic ; therapeutic use ; Adult ; Cytomegalovirus Infections ; drug therapy ; immunology ; Humans ; Liver Transplantation ; adverse effects ; immunology ; Lymphocyte Activation ; Male ; Middle Aged ; Pneumonia, Viral ; drug therapy ; immunology

OBJECTIVETo observe the effects of bagasse polysaccharide on the immune functions of immunosuppressed mice.

METHODSImmunosuppressed mouse models were established by intraperitoneal injections with cyclophosphamide followed by daily intragastric administration of bagasse polysaccharide. After the treatments, the mice were examined for immune organ weight index, phagocytotic function of the macrophages, delayed type hypersensitivity, serum IgM level following exposure to chicken red blood cells, formation of hemolytic plaques, T cell percentage and lymphocyte transformation.

RESULTSTreatment of the immunosuppressed mice with bagasse polysaccharide at the daily dose of 200 and 400 mg/kg significantly increased the weight of the immune organs, phagocytotic function of the macrophages, delayed type hypersensitivity, serum IgM level against chicken red blood cells, formation of hemolytic plaques, T cell percentage and lymphocyte transformation.

CONCLUSIONBagasse polysaccharide can enhance the immune functions of immunosuppressed mice.

Animals ; Cellulose ; chemistry ; Cyclophosphamide ; Female ; Immunocompromised Host ; immunology ; Lymphocyte Activation ; drug effects ; Macrophages ; immunology ; Male ; Mice ; Phagocytosis ; drug effects ; Polysaccharides ; pharmacology ; Random Allocation

This study was designed to detect the effects of Bazhen decoction on the proliferation and activation of T lymphocytes. T lymphocytes were isolated. The effects of Bazhen decoction on the prolifertion and activation of T lymphocytes, and on the secretion of IFN-gamma IL-2 from T lymphocytes, were detected by MTT, Flow cytometry and ELISA. Results showed that proliferation of T lymphocytes was promoted significantly by different concentration of Bazhen decoction; and after different time, the relationships of "the longer the time, the higher the concentration, and the more enhanced the proliferation" came to be apparent. After 72h, T lymphocytes were activated with different concentration of Bazhen decoction, the rate of CD69+ T cells increased signficantly, the secretion of IFN-gamma and IL-2 increased signficicantly, and the effect exhibited a dose-dependent manner. The results of this epxeriment indicated that Bazhen decoction could promote the proliferation and activation of T lymphocytes.
Cell Proliferation ; drug effects ; Cells, Cultured ; Drugs, Chinese Herbal ; pharmacology ; Flow Cytometry ; Humans ; Lymphocyte Activation ; drug effects ; immunology ; T-Lymphocytes ; cytology ; immunology