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@#Inflammatory caspase-11 senses and is activated by intracellular lipopolysaccharide (LPS) leading to pyroptosis that has critical role in defensing against bacterial infection, whereas its excess activation under pathogenic circumstances may cause various inflammatory diseases. However, there are few known drugs that can control caspase-11 activation. We report here that scutellarin, a flavonoid from Erigeron breviscapus, acted as an inhibitor for caspase-11 activation in macrophages. Scutellarin dose-dependently inhibited intracellular LPS-induced release of caspase-11p26 (indicative of caspase-11 activation) and generation of N-terminal fragment of gasdermin D (GSDMD-NT), leading to reduced pyroptosis. It also suppressed the activation of non-canonical nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome as evidenced by reduced apoptosis-associated speck-like protein containing a CARD (ASC) speck formation and decreased interleukin-1 beta (IL-1β) and caspase-1p10 secretion, whereas the NLRP3-specific inhibitor MCC950 only inhibited IL-1β and caspase-1p10 release and ASC speck formation but not pyroptosis. Scutellarin also suppressed LPS-induced caspase-11 activation and pyroptosis in RAW 264.7 cells lacking ASC expression. Moreover, scutellarin treatment increased Ser/Thr phosphorylation of caspase-11 at protein kinase A (PKA)-specific sites, and its inhibitory action on caspase-11 activation was largely abrogated by PKA inhibitor H89 or by adenylyl cyclase inhibitor MDL12330A. Collectively, our data indicate that scutellarin inhibited caspase-11 activation and pyroptosis in macrophages at least partly via regulating the PKA signaling pathway.
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Aim To explore the influence of metformin(a first-line drug for type 2 diabetes) on ATP-induced inflammasome activation and the release of interleukin-1β(IL-1β) by LPS-activated peritoneal macrophages, a commonly-used inflammatory cell model.Methods Peritoneal macrophages were elicited by intraperitoneal injection of 30 g·L-1 thioglycollate into C57BL/6 mice.Inflammasome was activated and cell pyroptosis was induced by LPS plus ATP treatment, and the pyroptotic cells were calculated after propidium iodide(PI) staining.The protein levels of IL-1β and caspase-1 expressed in the cells and released from them into the supernatant were evaluated by Western blot.Immunofluorescent microscopy was recruited to detect the subcellular distribution and fluorescent intensity of the purinergic P2X7 receptor(P2X7R).Results Metformin per se did not induce pyroptosis in LPS-activated peritoneal macrophages, but it significantly and dose-dependently increased cell pyroptosis induced by ATP treatment.At protein levels, maturated IL-1β(17 ku) could not be released from the cells upon single LPS or LPS plus metformin stimulation;but after ATP was added, maturated IL-1β was released into the supernatants of the cells.Moreover, metformin dose-dependently increased the protein levels of both maturated IL-1β and active caspase-1 released by the LPS-activated peritoneal macrophages upon ATP stimulation.Conclusion Metformin intensifies the activation of inflammasome and increases the release of active caspase-1 and maturated IL-1β upon ATP stimulation in the LPS-activated peritoneal macrophages, which should promote inflammatory responses.
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Aim To study the mechanism of cucurb-itacin E ( CuE )-induced autophagy in HeLa cells. Methods Improved MTT assay was adopted to meas-ure the effect of CuE on cell proliferation. Western blot was used to determine the phosphorylation levels of downstream signaling proteins of mTORC1 and the ex-pression of autophagy associated proteins. ResultsCuE inhibited the proliferation of HeLa cells in a dose-dependent manner, and the 24-h IC50 of CuE was 4. 01μmol· L-1 . CuE significantly inhibited the phospho-rylation of p70 S6 K in a time-and dose-dependent man-ner as evidenced by decreased phosphorylation levels of the mTORC1 substrate. Meanwhile, the expression of LC3-II, a marker for autophagosome formation, was elevated by CuE treatment, and was further increased in the presence of chloroquine. Furthermore, CuE re-duced the levels of p62/SQSTM1 . These results indi-cated that CuE induced autophagy in HeLa cells. The decreased levels of phosphorylated ULK1 S757 were posi-tively correlated with autophagy induction in HeLa cells. Conclusion CuE is likely to induce autophagy through inhibiting mTORC1 activity.
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AIM: Valproic acid (VPA) is a histone deacetylase inhibitor and is believed to have anti-tumor activity. The present study aims to investigate the effect of VPA on the, apoptosis and cytokine synthesis of human peripheral lymphocytes. METHODS: The activation and cytokine synthesis in lymphocytes in whole blood stimulated with phorbol dibutyrate (PDB) and ionomycin were evaluated with flow cytometry after fluorescent staining. The mitochondrial membrane potential was examined using 3, 3-dihexyloxacarbocyanine iodide [DiOC6(3)]staining. RESULTS: VPA at low doses (1 and 5 mmol/L) promoted CD69 expression in activated lymphocytes, whereas it turned to inhibit the expression of CD69 at a high dose (25 mmol/L). Meanwhile, VPA at low doses increased the mitochondrial membrane potential, while a high dose of VPA decreased it in activated lymphocytes. Furthermore, interleukin-2 (IL-2) synthesis was enhanced by low doses of VPA but inhibited by a high dose. However, interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) synthesis were dose-dependently enhanced by VPA as compared with those of PDB plus ionomycin-treated cells. CONCLUSION: VPA exerts biphasic effect on the further activation and apoptosis of human peripheral lymphocytes stimulated with mitogens and exhibits differential activity on the synthesis of several important cytokines in human lymphocytes.
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AIM: To investigate the effects of uric acid sodium salt (UANa) as adjuvant on humoral and cellular immune response in BALB/c mice. METHODS: BALB/c mice were immunized with trichosanthin (TCS) as antigen together with UANa suspension as adjuvant. The antibody titers of IgG were detected by enzyme-linked immunosorbent assay. Dendritic cells (DC) were induced in vitro, the phenotypes of DC were analyzed by flow cytometry and the effect of UANa on DC maturity was evaluated. A delayed-type hypersensitivity (DTH) model was used to analyze the effect of UANa on cellular immune responses in vivo. The in vitro proliferation of lymphocytes was determined by ConA stimulation. RESULTS: Freunds adjuvant greatly enhanced the antibody response of mice to TCS, while UANa adjuvant failed to promote the antibody response but significantly reduced the antibody response as compared to TCS only. No effect of UANa on the expression of CD11c and CD83 in DC was observed by flow cytometry analysis. However, UANa significantly enhanced the expression of MHC II molecule. In the DTH model, UANa enhanced the degree of allergen-induced ear swelling and promoted the ability of lymphocyte proliferation in vitro. CONCLUSION: UANa suspension as adjuvant significantly enhances the cellular immune response but inhibits the humoral immune response to a certain degree, suggesting that UANa has potential application in the vaccine research.
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AIM: To investigate the anti-HIV-1 activity of five anthraquinone derivatives (emodin,rhein,chrysophanol,physcion and aloe-emodin) in vitro.METHODS: Viral replication was estimated by observation of cytopathogenesis and measurement of HIV-1 p24 antigen production in HIV-1ⅢB acutely infected C8166 cells. The anti-HIV-1 activity was evaluated by the 50% effective concentrations (EC50) and selective indexes (SI) of these derivatives.RESULTS: These anthraquinone derivatives inhibited HIV-1ⅢB replication on syncytia formation induced by HIV-1ⅢB infection with EC50 mean values of (11.44±0.93)μmol/L (emodin),(51.28±2.86)μmol/L (rhein),(90.58±2.30)μmol/L (chrysophanol),(8.59±0.38)μmol/L (physcion) and (0.89±0.08)μmol/L (aloe-emodin),respectively. The p24 antigen production with EC50 mean values were (11.61±0.56)μmol/L (emodin),(12.35±4.73)μmol/L (rhein),(39.63±2.87)μmol/L (chrysophanol),>250 μmol/L (physcion) and (2.75±0.20)μmol/L (aloe-emodin) respectively. CONCLUSION: These structurally-related chemicals show different anti-HIV-1 activity in vitro. Among them,aloe-emodin is the most potent inhibitor to HIV-1 replication.
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Major histocompatibility complex (MHC) tetramer technology offers a powerful means to study specific T cell populations of interest. To investigate the immune response of H-2Db-restricted CD8+ T cells in immunotherapy, we prepared the H-2Db tetramer and verified its effectiveness in enumerating the CD8+ T cells specific for the lymphocytic choriomeningitis virus (LCMV). First, the cDNA encoding H-2Db heavy chain was cloned by RT-PCR from the spleen of a C57BL/6 mouse. The expression vector for H-2Db-BSP, i.e. the ectodomain of H-2Db fused to a BirA substrate peptide (BSP), was constructed and overexpressed in E. coli BL21(DE3). Then, the denatured H-2Db-BSP was refolded in the presence of human beta2-microglobulin as well as the GP33-41 peptide (KAVYNFATC, KAV) of LCMV. The biotinylated H-2Db/KAV molecules were purified, then bound to streptavidin-PE and tetramerized. Finally, the prepared H-2Db KAV tetramer reagent was verified by detecting the CD8+ T cells specific for HCMV in KAV peptide vaccinated C57BL/6 mouse, with a mouse receiving subcutaneous injection of only adjuvant as negative control. The results showed that the tetramer positive rates were 0.27%, 0.11%, and 0.24% within the CD8+ T cell populations in the peripheral blood, draining lymph nodes, and spleen of vaccinated mouse, respectively. There was only very low background staining (< or = 0.01%) of those samples from the control mouse. Beside, the best results were achieved in the staining of the peripheral blood sample. In conclusion, the established procedure of preparing H-2Db tetramer will facilitate the study of the immune responses of antigen-specific CD8+ T cells in the experimental immunotherapy on the mice with H-2Db allele background.
Subject(s)
Animals , Male , Mice , Antibody Specificity , CD8-Positive T-Lymphocytes , Allergy and Immunology , H-2 Antigens , Genetics , Histocompatibility Antigens Class I , Genetics , Immunologic Techniques , Lymphocytic choriomeningitis virus , Allergy and Immunology , Mice, Inbred C57BL , T-Cell Antigen Receptor Specificity , Allergy and ImmunologyABSTRACT
AIM To investigate the effect of recipient kidney function by CsA coadministration Ber used to induce immune tolerance in rats of allogenic cardiac transplantation. METHODS The authors established the SD to Wistar rats heterotopic cardiac transplantation model by Onos methods.Observe the cardiac allograft survival and levels of BUN and Cr in the recipients plasma. The recipients were classified into 5 groups randomly after heterotopic cardiac transplantation were performed. Group A (Wistar to Wistar)): Received placebo intraperitoneal injected for 21 days; Group B (SD to Wistar): Saline intraperitoneal injected for 21 days; Group C (SD to Wistar):CsA 2 mg?kg -1 ?d -1 intraperitoneal injected for 21 days; Group D(SD to Wistar):Ber 16 mg?kg -1 ?d -1 gastrointubation for 21 days; Group E(SD to Wistar): Ber 16 mg?kg -1 ?d -1 gastrointubation coadministration CsA 2 mg?kg -1 ?d -1 ip for 21 days. RESULTS The levels of BUN and Cr in recipint plasma is lower evidently compare with the group with CsA ip simply. CONCLUSION Ber can reduce the renal toxicity in recipients by CsA which was intraperitoneal injected (ip) over a long period time.
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AIM: To study the effect of trichosanthin (TCS), a type I ribosome-inactivating protein, on the induction of apoptosis in human leukemic cell line HL-60 cells and the influence of cycloheximide (CHX) on TCS-induced apoptosis. METHODS: Flow cytometry together with fluorescent microscopy were adopted to investigate the apoptotic cell death in HL-60 cells treated with TCS. RESULTS: Flow cytometric analysis indicated that TCS was able to induce significant apoptosis in HL-60 cells. The rates of apoptotic cells in HL-60 cells treated with TCS (20 mg/L) for 48 h was 48.7%±2.3%(±s), which was significantly higher than that of control (6.3%±1.0%)(P＜0.05). Under the same condition, the rate of apoptosis caused by CHX (5 mg/L) was 65.3%±3.9%. TCS-induced apoptosis was further confirmed by fluorescent microscopy observation and DNA gel electrophoresis, in which typical nuclear morphological changes such as chromatin condensation, nuclear fragmentation, were observed in many of the cells treated with TCS， and DNA extracted from these cells displayed typical ladder pattern. Furthermore, the effect of TCS was significantly enhanced with the pretreatment of CHX (0.2 mg/L) which did not induce any significant apoptosis when used at 0.2 mg/L seperately. TCS-induced apoptosis was time- and dose-dependent. CONCLUSION: TCS was able to induce apoptosis in HL-60 cells, which was enhanced by CHX. It was suggested that TCS-induced apoptosis was independent of new protein synthesis.
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AIM: Peripheral blood mononuclear cells (PBMC) were cultured in vitro to study the effect of gossypol, a polyphenolic antifertility agent, on the activation of normal human T cells. METHODS: Double fluorescent staining together with flow cytometry was adopted to analyze the influence of gossypol on expression of the early activation antigen CD69 on T-lymphocytes under stimulation of mitogen or phorbol ester. RESULTS: Analysis of T cell activation in vitro revealed that preincubation of PBMC with 100 μmol/L gossypol could completely inhibit the expression of early activation marker CD69 on CD3+ T cells in response to 10 mg/L PHA, and block T cell activation by 10-7 mol/L PDB as well. The suppression of CD69 expression was dose-dependent and IC50 of gossypol on PDB and PHA were (35.7±2.9) μmol/L and (32.8±1.5) μmol/L(眘), respectively. Besides, gossypol had similar inhibitory effect on CD69 expression of CD3- lymphocytes. However, it did not have any significant effect on T cell surface molecule CD3 down-regulation. CONCLUSION: Gossypol could inhibit T cell activation in vitro in response to polyclonal activators, both PHA and PDB, suggesting that its action site may be at PKC or its downstream and that gossypol possessed potential immuno-regulatory effect.
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AIM: To investigate the effect of berberine (Ber) on the activation and proliferation of T lymphocytes and its mechanism of action. METHODS: Whole peripheral blood from normal subjects was stimulated with phytohemagglutinin (PHA) or phorbol ester (PDB) plus ionomycin (Ion) and the expression levels of CD69 and CD25 were evaluated with flow cytometry after the staining with appropriate fluorescent monoclonal antibody. The distribution of cell cycles was analyzed by propidium iodide staining and dead cells by 7-aminoactinomycin live staining. RESULTS: 100 ?mol/L and 50 ?mol/L of Ber had significant inhibition of the expression of CD69 on T cells stimulated with PDB plus Ion or PHA, while effect of 25 ?mol/L Ber was not significant. And as time of action extended, the extent of inhibition decreased. For the expression of CD25, Ber at the concentrations as above all exerted significant inhibitory effect in a dose-dependent manner. Moreover, Ber could block lymphocytes cell cycle progression from G_0/G_1 phase to S and G_2/M phase without phase specificity. Besides, live staining analysis revealed that Ber did not have significant cytotoxicity on lymphocytes. CONCLUSIONS: Ber significantly inhibits the expression of early and mid activation antigens of T cells and also blocks the progression of lymphocytes cell cycles. These results suggest that Ber exerts immunosuppression effect through inhibiting the activation and proliferation of T cells.
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AIM: To study the influence of status of stimulator cells on activation of responder T cells in mixed lymphocyte reaction (MLR), so as to provide some basis for clinical transplantation. METHODS: Stimulator cells were pretreated differently before mixed lymphocyte culture (MLC) to change their functional status, fluorescence conjugated antibodies and flow cytometry were used to detect expression of CD69 by responder T cells at several different time points. RESULTS: The expression percentages of CD69 by responder T cells in MLCa group (stimulator cells were pre-activated) were significantly higher than those in MLC group (stimulator cells were not pre-activated) at 24, 48 and 72 hours of culture, respectively (5 21%?0 24% vs 1 98%?0 33%, 29 81%?0 85% vs 20 65%?1 00% and 39 61%?1 62% vs 13 49%?0 60%, P
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AIM: To investigate the amount and patterns of expressing CD69 , IL-4 and IFN-? on TCRV?24 +NKT cells, and compare with that of CD3 +T cells from human peripheral blood in response to in vitro stimulation. METHODS: The whole blood was stained with three-color immunofluorescence directly or after cultured with PDB+ionomycin(Ion) for 6 h, then the mononuclear cells were separated by lysing red blood cells. The expression rates of CD69, IL-4 and IFN-? on TCRV?24 +NKT cells and CD3 +T cells were estimated by flow cytometer. RESULTS: As a proportion of mature T cells, the ratio of TCRV?24 + NKT cells to CD3 +T cells was about(1.34?0.42)%. The expression rates of CD69 on TCRV?24 + NKT cells and CD3 +T cells in response to PDB + Ion for 6 h were (96.71?1.33)% and (98.60?0.47)%, respectively, while the ratio were (11.47?2.86)% and (1.07?0.45)% in the unstimulated group, and there were significant difference between them. The expression rates of IL-4 and IFN-? on TCRV?24 +NKT cells stimulated with PDB+Ion for 6 h were (48.62?2.44)% and (46.65?8.91)%, respectively ,which were significantly higher than that of unstimulated group [(31.57?3.31)%, (13.45?6.29)%] and that of stimulated CD3 +T cells, though the expression rates on stimulated CD3 +T cells were significantly higher than that of unstimulated CD3 +T cells. CONCLUSIONS: There is small amount of NKT cells in adult human peripheral blood. The expression rates of IFN-? and IL-4 on these lymphocytes are higher than CD3 +T cells, suggesting that NKT cells are important immunomodulatory cells in special microvironments.
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AIM: To investigate whether wheat germ agglutinin (WGA) could induce apoptosis in mouse fibroblast cell line L929 and the possible molecular mechanism underlying. METHODS: The cells were exposed to WGA or its succinylated form (sWGA) for 24 h and both attached cells and the cells in supernatant were collected. The percentages of apoptotic cells were estimated by flow cytometry after staining with propidium iodide. Cell morphology was observed under fluorescence microscope after staining the cells with acridine orange. RESULTS: WGA treatment resulted in significant increase of the low DNA content peak (sub-G 1) that representing apoptotic cells, whereas sWGA did not. Morphologic study demonstrated that exposure to WGA induced nuclear fragmentation while sWGA not. CONCLUSION: These results indicate that WGA (specific for both sialic acid and GlcNAc) induces apoptosis in L929 cells, whereas sWGA (specific only for GlcNAc) does not. It is possible that binding to sialic acid residues on the cell surface of L929 is essential for WGA to induce apoptosis. Apoptosis induction may be, at least in part, involved in the cytotoxicity of WGA. [
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Objective:To develop the mechanistic model for the reorientation of T cell receptors during immunological synapse formation.Methods:Based on the theory of energy transfer during double-molecular reactions in the context of classical fluid mechanics,a vortex-driven model was proposed where in the coupled receptor/ligand molecules within the immunological synapse recruit the T cell receptors.Results:The model results indicated that driven by the consecutive vortexes with specific combinations of strengths and acting frequencies of vortexes,TCR transport speed can reach the values matching up to the experimental measurements(0.04-0.1 ?m/s).Conclusion:The model demonstrated that during the coupling,the membrane-tethered receptor-ligand pairs may transform their binding energies into the rotational energies of the reactants,thereby leading to the vortexes of the surrounding water continuum insider and outside the T cell,and these resulting vortexes may function as the engines for the reorientation of T cell receptors.
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AIM: To investigate the details of age-related changes of T lymphocytes in order to seek for sensitive biomarker for immunosenesence. METHODS: Heparin anticoagulated venous blood was collected freshly from young (20-35 years) and elderly (50-75 years) volunteers and three or four color immunofluorescence staining was performed. The nucleated cells were acquired and the phenotypes of T lymphocyte subpopulations were analyzed with flow cytometry. RESULTS: There was no significant difference in percentages of pan-T (CD3 +), helper T (CD4 +) and cytotoxic (CD8 +) T subsets between young and elderly, whereas the density of CD3 molecule (MFI) on T cells in elderly group decreased significantly. It was also found that the rates of CD44 + and CD62L + T cell subsets in young group did not have statistical difference from elderly. However,the rates of CD95 + pan-T, helper T and cytotoxic T subsets of elderly group were all markedly higher than that in young group. CONCLUSIONS: The relative rates of T cell and its subsets displayed no age-related changes while the density of CD3 was down-regulated during aging in these groups investigated. Moreover, the expression percentage of CD95 (Fas) on T cells increased as aging, suggesting that it is a potential biomarker for evaluating immunosenescence.
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AIM: To study the effect of natural killer(NK)-cells on graft-versus-host disease(GVHD), graft rejection, engraftment and reconstituting of hematopoiesis in mouse allogeneic bone marrow transplantation. METHODS: Lethally irradiated BALB/c(H-2 d) mice were transplanted with C57/6j(H-2 b) bone marrow containing donor peripheral T cells and/or NK cells. Recipients CD 34 + cell counts and the expression of H-2K b+ cell were detected by flow cytometry, peripheral white blood cell(WBC) was detected by auto-cytometry, and the recipients survival rates, GVHD, engraftment and hematopoiesis recovery were then observed. RESULTS: In the group of transplanted with NK cells infusion, the incidence of GVHD was evidently lessened, the survival rates, WBC and CD 34 + cell counts and the expression of H-2K b+ cell were significantly high than that without NK cells infusion. CONCLUSION: In mouse allogeneic bone marrow transplantation, alloreactivity NK cells prevent GVHD, reduce graft rejection, and promote engraftment and reconstituting of hematopoiesis. [
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Objective To investigate the status of cellular immunity from Th cell polarization in pa-tients with different courses of condyloma acuminatum(CA).Methods The isolated PBMC were polarized by PHA and self-plasma for72hours,then followed by two-color immunofluorescent staining with anti-CD4-PE and anti-CCR5-FITC,or with anti-CD4-FITC and anti-CCR3-PE.Finally the stained cells were analyzed by flow-cytometry.Results The percentages of Th1/Th2cells of the short-course group and long-course group were(25.82?2.22)%/(14.80?1.14)%and(12.20?1.37)%/(13.74?0.99)%,respectively;the differ-ences between normal control and two CA groups were significant(P
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AIM: To investigate the effect of cycloheximide on the T cells activation by mitogen in vitro with CD69 expression as activation marker for the application of this drug clinically. METHODS:Lymphocytes were isolated from lymphoid nodes of C57BL/6 mouse. The cells were preincubated with cycloheximide(CHX), 5% serum containing CHX respectively for an hour, then further incubated with polyclonal activators (Con A or PDB). Harvesting the cells after whole incubation for 24 h, we estimated the expression rates of CD69 on T cells by flow cytometry following two-color immunofluorescent staining. RESULTS: The expression rates of CD69 on the T cells preincubated with CHX, serum containing CHX after the stimulation in response to Con A or PDB all showed significant difference with the expression rates of control group, respectively ( P
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AIM: To investigate the influences of protein kinase C(PKC) inhibitors on the expression of interleukin-2(IL-2) and interferon-?(IFN-?) by in vitro activated T-lymphocytes. METHODS: Double fluorescent staining together with flow cytometry was adopted to detect intracellular cytokines and to analyze the effects of H7 and gossypol on IL-2 and IFN-? expression levels of T-lymphocytes stimulated with phorbol ester (PDB)+ionomycin(I) in the presence of monensin.RESULTS: The expression rates of IL-2 and IFN-? of CD3 + T cells stimulated with PDB+I for 4 h were 16.64?2.04 and 25.81?3.53( ?s ), respectively, which were significantly higher than that of control (1.06?0.22 and 3.12?0.77)( P