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T Jung

Publications and source records attributed to T Jung.

At least 55 records · Page 3Linked to original sources
PubMed1997

A subset of CD8+ T cells from allergic patients produce IL-4 and stimulate IgE production in vitro.

BACKGROUND AND OBJECTIVE: A subset of IL-4 producing CD8+ T cells was recently identified in HIV patients. Based on these findings we examined whether IL-4 producing CD8+ T cells would also be present in allergic patients and what would be the functional relevance of this T-cell population. METHODS: We investigated the role of CD8+ T cells in IgE production of allergic diseases by analysing the cytokine profile of individual CD4+ and CD8+ T cells. RESULTS: In allergic patients about twice as many CD4+ T cells and six times as many CD8+ T cells produced IL-4 as in non-allergic controls. In contrast the frequency of IFNgamma+ T-cell subsets did not significantly differ between the allergic and non-allergic individuals. The frequency of IL4+ CD8+ T cells correlated with the level of serum IgE. Coculture experiments with T cells or purified CD8+ T cells together with autologous B cells indicated that CD8+ T cells enhanced IgE in vitro, but not IgM production, even when they were physically separated from B cells. This effect could be partially blocked by addition of an IL-4 binding protein, a soluble IL-4 receptor indicating that IL-4 is involved in CD8+ T-cell mediated IgE production. CONCLUSIONS: These data indicate a positive role of IL-4 secreting CD8+ T cells in IgE regulation in allergic patients.

Adult↗
PubMed1997

Nitric oxide inhibits the secretion of T-helper 1- and T-helper 2-associated cytokines in activated human T cells.

Mechanisms regulating the balance of T-helper 1 (Th1) and T-helper 2 (Th2) immune responses are of great interest as they may determine the outcome of allergic and infectious diseases. Recently, in mice, nitric oxide (NO), a powerful modulator of inflammation, has been reported to preferentially down-regulate Th1-mediated immune responses. In the present study, we investigated the effect of NO on the production of Th1- and Th2-associated cytokines by activated human T cells and human T-cell clones. Cytokine secretion was measured in the presence of the NO-donating agents 3-morpholinosydnonimine (SIN-1) and S-nitroso-N-acetylpenicillamine (SNAP). Both NO-donors markedly inhibited the release of interferon-gamma (IFN-gamma), interleukin-2 (IL-2), IL-5, IL-10 and IL-4 by anti-CD3 activated T cells. A preferential inhibition of Th1-associated cytokines was not observed. Neither was nitrite found in the supernatants of activated T cells, nor was specific mRNA for inducible and constitutive NO synthase detectable, indicating that T cells themselves did not contribute to the observed effect of the NO donors. Costimulation with anti-CD28 monoclonal antibodies (mAb) prevented SIN-1/SNAP-mediated down-regulation of cytokine production only in part. In contrast, when T cells were stimulated by phorbol-ester and ionomycin, they were refractory to SIN-1-induced inhibition of cytokine production. When SIN-1 was added after the onset of anti-CD3 stimulation, the inhibitory effect was found to be less pronounced, indicating that SIN-1 may interfere with early signal transduction events. The addition of superoxide dismutase (SOD) and catalase did not restore the effects of SIN-1, demonstrating that the inhibition of cytokines was due to NO and not to oxygen intermediates. Furthermore, 8-Br-cGMP-mediated increase of intracellular cGMP caused the same pattern of cytokine inhibition as observed with SIN-1 and SNAP. Using a single cell assay, these agents were shown to reduce the frequency of IFN-gamma-producing T cells, suggesting that not all T cells are susceptible to SIN-1/SNAP. However, cytokine production by purified T-cell subpopulations (CD4+, CD8+, CD45RA+, and CD45RO+) was equally impaired by NO donors. In conclusion, in contrast to the murine system, our results do not provide evidence that NO preferentially inhibits Th1-cytokine secretion of activated human T cells in vitro.

CD3 Complex↗
PubMed1997

Extracellular calmodulin-binding proteins in body fluids of animals.

The extracellular calmodulin-binding proteins (CaMBPs) were investigated in body fluids of animals by using the biotinylated calmodulin gel overlay method. Four major CaMBPs with molecular masses of 24, 31.5, 44/45 and 94 kDa were detected in serum, two of 24 and 63 kDa in bovine milk and three of 14, 24 and 52 kDa in human saliva. It suggested that extracellular CaMBPs exist commonly in body fluids of animals, and this result may provide a new clue for understanding the role of extracellular calmodulin.

Animals↗
PubMed1996

Stimulation of IgE and IgA production by CD45RA T helper cells in atopic patients.

The role of CD45RA T cells on allergen-dependent lymphocyte functions was analyzed in atopic patients. As compared with age-matched nonatopic controls, atopic patients exhibited a significantly (p < 0.01) increased frequency of CD45RA T cells in peripheral blood. Concentration of serum IgE correlated with increases in this T cell subset. In contrast to nonatopic controls, not only CD45RO but also CD45RA T cells from atopic patients provide help for allergen-stimulated IgE and IgA production, and they act in a synergistic fashion. Transwell coculture experiments revealed that optimal production of IgE and IgA required physical contact of CD45RA T cells with B cells. Freshly prepared and in vitro-activated CD45RO and CD45RA T cells from atopic patients showed an increased expression of CD40 ligand when compared with nonatopic individuals. In addition, CD45RA (and CD45RO) T cells from atopic individuals produced IL-4, IL-5, and IFN-gamma when stimulated with mitogens. Whereas stimulation of normal lymphocytes with tetanus Ag was followed by conversion of the CD45RA to the CD45RO phenotype, T cells from atopic donors did not acquire the CD45RO isoform to the same degree despite T cell activation. In atopic patients, addition of IL-4 to anti-CD3/anti-TCR stimulated CD45RA T cell prevented the shift towards the CD45RO phenotype. These data indicate that a subset of CD45RA T cells plays a unique role as effector T cells regulating IgE and IgA production in atopic patients.

Allergens↗
PubMed1996

Interleukin-13 is produced by activated human CD45RA+ and CD45RO+ T cells: modulation by interleukin-4 and interleukin-12.

Interleukin (IL)-13 is a cytokine originally identified as a product of activated T cells. Little is known however, about IL-13 production by human T cells and its modulation by other cytokines. Here, we show that IL-13 is produced by activated human CD4+ and CD8+ CD45RO+ memory T cells and CD4+ and CD8+ CD45RA+ naive T cells. In contrast, IL-4, which shares many biological activities with IL-13, is only produced by CD45RO+ T cells following activation. Analysis of intracellular cytokine production by single CD45RA+ and CD45RO+ T cells indicated that IL-13 continued to be produced for more than 24 h after stimulation, whereas IL-4 could not be detected after 24 h. These data were confirmed by measurement of specific mRNA and suggest that IL-13, unlike IL-4, but like interferon-gamma (IFN-gamma), is a cytokine with long-lasting kinetics. The majority of human CD45RO+ T cells produced IL-4 and IL-13 simultaneously. In contrast, IFN-gamma protein was generally not co-expressed with IL-4 or IL-13. IL-4 added to primary cultures of highly purified peripheral blood T cells activated by the combination of anti-CD3+anti-CD28 mAb enhanced IL-13 production by CD45RA+ and to a lesser extent by CD45RO+ T cells. Under these conditions, however, IL-12 inhibited IL-13 production by CD45RA+ T cells and to a lesser extent by CD45RO+ T cells in a dose-dependent fashion. These inhibiting effects were not related to enhanced IFN-gamma production induced by IL-12, since IFN-gamma by itself did not affect IL-13 production. Collectively, our data indicate that IL-13 is produced by peripheral blood T cells which also produce IL-4, but not IFN-gamma, and by naive CD45RA+ T cells which, in contrast, fail to produce IL-4. These observations, together with the long-lasting production of IL-13, suggest that IL-13 may have IL-4 like functions in situations where T cell-derived IL-4 is still absent or where its production has already been down-regulated.

Adjuvants, Immunologic↗
PubMed1996

Effects of ionizing- and UV B-radiation on proteins controlling cell cycle progression in human cells: comparison of the MCF-7 adenocarcinoma and the SCL-2 squamous cell carcinoma cell line.

MCF-7 and SCL-2 cells were irradiated with UV B-radiation or with 137Cs gamma-radiation, in order to investigate cell cycle checkpoint control mechanisms. Effects of both qualities of radiation were investigated for the two cell lines in regard to p53 protein levels, and alterations in Cdk1 (cyclin dependent kinase 1) and Cdk2 phosphorylation were monitored. SCL-2 cells constitutively overexpressed a form of p53 protein whose abundance remained unchanged after irradiation, whereas MCF-7 cells expressed wild type p53 whose abundance increased after irradiation. Accordingly, MCF-7 cells showed a strong G1 phase arrest, whereas SCL-2 cells were only delayed in S phase (after UV B-irradiation) and arrested in G2 phase (after gamma-irradiation and UV B-irradiation), as monitored by flow cytometry. In MCF-7 cells increased p53 levels were observed for up to 30 h after gamma-irradiation and up to 20 h after UV B-irradiation. Only in SCL-2 cells was there a significant radiation induced inactivation of Cdk1 by hyperphosphorylation. This effect was prevented by culturing cells in the presence of caffeine after irradiation. After UV B-irradiation the inactivation of Cdk1 was less pronounced and only partially diminished in the presence of caffeine. No alteration in Cdk2 phosphorylation was observed after irradiation in either cell line.

Adenocarcinoma↗
PubMed1996

UV-B-induced cell cycle perturbations, micronucleus induction, and modulation by caffeine in human keratinocytes.

UV-B-induced perturbations of cell cycle progression in asynchronous human keratinocytes were analysed during two cell cycles with respect to their cell cycle stage at the time of irradiation using BrdUrd/Hoechst flow cytometry. Exponentially growing SCL-2-keratinocytes exposed to UV-B radiation showed a short delay in G1-phase exit and were blocked in the S and G2/M phases of the first cell cycle. UV-A wavelengths did not show any detectable effect on cell cycle progression. In contrast, 137Cs-irradiation of these cells induced a temporary G2 block only. Micronucleus frequency increased in gamma-irradiated cells as soon as the cells started to divide and reached a plateau when most of the cells had divided. Continuous treatment with caffeine starting immediately after 137Cs gamma-irradiation prevented accumulation of cells in G2 phase, but did not influence the frequency of micronuclei. In UV-B-irradiated keratinocytes, however, the damage-induced cell cycle perturbations were merely reduced by caffeine, but not eliminated. Compared with gamma-irradiation a moderate induction of micronuclei was observed in UV-B-irradiated cells. Caffeine, however, potentiated the induction of micronuclei by UV-B. These different effects on cell cycle kinetics and micronucleus induction indicate different mechanisms of DNA damage caused by UV-B- and gamma-irradiation that may be repaired through different pathways.

Caffeine↗
PubMed1996

Human keratinocytes constitutively express IL-4 receptor molecules and respond to IL-4 with an increase in B7/BB1 expression.

In certain pathological conditions, such as atopic dermatitis, interleukin-4 (IL-4) can be detected in the skin. As the role of this cytokine in inflammatory skin lesions is not completely clear, we investigated its biological effects on skin keratinocytes. It was found that freshly isolated as well as cultured keratinocytes obtained from normal individuals express mRNA for the IL-4 receptor (IL-4R) and produce IL-4R protein, as determined by flow cytometry. Moreover, IL-4 induced a proliferative response in keratinocytes after 1 day of culture and enhanced B7/BB1 expression in these cells. B7-2 (CD86) mRNA and protein were neither detected on untreated nor IL-4 treated keratinocytes. In contrast to interferon-gamma (IFN-gamma), IL-4 did not induce ICAM-1 (CD54) or HLA-DR-expression. Keratinocytes which had been treated with IL-4 showed an enhanced ability to stimulate allogeneic T-cell proliferation in the presence of staphylococcus enterotoxin B (SEB), (p < 0.01). Neutralizing anti-B7/BB1 monoclonal antibodies did not block this effect. These results indicate that other molecules than B7/BB-1. HLA-DR or ICAM-1 on IL-4-activated keratinocytes may be involved in T-cell stimulation. In conclusion our results suggest that locally produced IL-4, besides modulating keratinocyte membrane molecules, may enable keratinocytes to interact with skin infiltrating lymphocytes.

Antigens, CD↗
PubMed1995

Interleukin-4 and interleukin-5 are rarely co-expressed by human T cells.

Interleukin (IL)-4 and IL-5 are two cytokines which synergize in the induction of several biological effector functions. They are produced by mouse and human T helper 2 (Th2) and T helper 0 (Th0) cells. Little is known about the regulation of the two cytokines at the single-cell level. Here we show, using a flow cytometric intracellular staining technique, that IL-4 and IL-5 are predominantly produced by different human peripheral CD4+ and CD8+ T cells, whereas interferon (IFN)-gamma and IL-2 are produced by the same cells. In contrast, cloned human Th0 and Th2 cells were able to produce IL-4 and IL-5 simultaneously. The segregation of IL-4 and IL-5 in activated peripheral T cells was found within 72 h of activation upon anti-CD3 or phorbol ester + ionomycin stimulation. The kinetics of IL-4 and IL-5 production were different at the mRNA and the intra- and extracellular protein level, indicating that the cytokines are regulated differently. T cells from three patients with hyper-IgE syndrome did not display a substantial proportion of IL-4/IL-5 double-positive cells. However, simultaneous production could be induced in normal human T cells after prolonged stimulation with a minimum of two restimulation cycles. We conclude that the simultaneous production of IL-4 and IL-5 is a feature of repetitively activated human T cells.

Base Sequence↗
PubMed1995

UV irradiation of chromosomal DNA and its effect upon MPF and meiosis in mammalian oocytes.

Bovine oocytes were irradiated at germinal vesicle (GV) or metaphase II (MII) stage, after Hoechst staining, with chromosomally focused UV-C (254 nm) or UV-A ( > 330 nm). UV-C irradiation at GV stage did not inhibit germinal vesicle breakdown (GVBD) or chromosomal condensation; spindle formation was abolished and maturation promoting factor (MPF) levels failed to increase. UV-A irradiation at GV stage caused meiotic arrest at anaphase I; MPF levels were lower than control. UV-C irradiation at MII stage led to subsequent abnormal parthenogenetic activation when MPF levels failed to decrease. A normal male but no female pronucleus was formed at fertilization. UV-A irradiation at MII stage also caused abnormal activation; MPF levels declined normally. A normal male and abnormal female pronucleus formed at fertilization. UV-A irradiation results have implications for oocyte evaluation during development using Hoechst staining. UV-C irradiation is a potential means for oocyte enucleation in nuclear transfer.

Animals↗
PubMed1995

Measurement of tooth displacements and mouthpiece forces during brass instrument playing.

In order to assess the actual load on front teeth and tooth supportive tissue during brass instrument playing, a measuring system was developed permitting simultaneous recordings of mouthpiece forces and incisor deflections. By the application of strain gauges, the mouthpiece itself was converted into an extra-oral force transducer, whilst an intra-oral metal appliance similar to a removable partial denture served as the base for strain gauge transducers sensing incisor displacements. The measurements only slightly affected the handling of the instruments under examination (trumpet, french horn, tenor horn, and tuba) and yielded the following average results for three to five players per instrument: peak force values were in the range of 29 N (tuba) to 50 N (trumpet), and the respective peak displacements were 43 microns and 100 microns.

Biomechanical Phenomena↗
PubMed1995

Decreased frequency of interferon-gamma- and interleukin-2-producing cells in patients with atopic diseases measured at the single cell level.

BACKGROUND: Recently, diminished interferon-gamma (IFN-gamma) and increased interleukin (IL-4 production in peripheral blood mononuclear cells (PBMCs) from atopic patients have been described by several groups, measured as total cytokine content in culture supernatants. These studies suggested a predominance of TH2-like cells producing large amounts of IL-4 in atopic patients. It is not clear whether the reported cytokine imbalances are the result of an alteration in the distribution of specific T-cell subsets or whether intrinsic dysregulation in cytokine production is a characteristic of atopic individuals. OBJECTIVE: This study examined the production of IFN-gamma, and IL-2 in PBMCs from atopic patients at the single cell level with the use of freshly isolated lymphocytes. METHODS: We recently described a flow cytometric assay in which three-color analysis was used to study the production of a cytokine of interest in a T-cell subpopulation defined by two cell surface markers. PBMCs from 23 atopic patients and 14 control subjects were stimulated with phorbol ester and ionomycin for 5 hours. PBMCs from seven patients and seven control subjects were also cultured with immobilized anti-CD3 antibodies for 24 hours. Cells were fixed, made permeable, and stained for intracellular cytokines in combination with cell surface markers CD3, CD8, and CD45RO. Cytokine-producing cells were analyzed by gating on T-cell subsets. RESULTS: IFN-gamma-producing cells were significantly decreased (p < 0.05) in CD4+ T cells but not in CD8+ T cells of atopic patients. CD45R0+ and CD45R0-T cells showed a decreased proportion of IFN-gamma-producing cells (p < 0.05 and p < 0.01, respectively). IL-2 production was diminished in all T-cell subsets (p < 0.01). The number of IL-4-producing cells was not elevated, and such cells were exclusively found in the CD45RO+ T cells. Analysis of culture supernatants of sorted CD45RO+ T cells for IL-4 and IFN-gamma production confirmed these results. CONCLUSION: Our findings provide evidence that a reduced IFN-gamma production in atopic patients is due to an intrinsic defect selectively found in the CD4+ T cells. Because IL-2 production was markedly decreased but IL-4 production was unchanged, our data demonstrate a deficiency in the ability of atopic T cells to produce TH1-like cytokines on stimulation with phorbol ester, ionomycin, or anti-CD3 monoclonal antibodies.

Adolescent↗
PubMed1994

MPF components and meiotic competence in growing pig oocytes.

Growing pig oocytes (< or = 90 microns in diameter) are unable to resume meiosis in vitro. The objective of our present experiments has been to identify the reasons for meiotic competence in these cells. By comparing histone H1 kinase activity in growing and fully grown oocytes we demonstrate that incompetence is associated with an inability to activate H1 kinase in growing oocytes. Immunoblotting was used to determine whether this kinase inactivity resulted from a lack of either p34cdc2 protein or B-type cyclin. The results established that each of these cell cycle molecules are present in comparable amounts in both growing and fully grown oocytes. In the third series of studies experiments were carried out in an attempt to induce p34cdc2 activation during growth. Treatment with okadaic acid, an inhibitor of phosphatase 1 and 2A known to stimulate and accelerate the transition into M-phase of the meiotic cycle in a number of different species, was able to induce p34cdc2 kinase activity and facilitated the G2- to M-phase in growing oocytes. We conclude that although growing oocytes in pigs have sufficient key cell cycle components for the G2 to M transition, they remain incapable of converting these components to active maturation-promoting factor (MPF) until growth is virtually completed. Inhibition of phosphatase 1 or 2A induces the formation of active MPF during growth by an as yet unidentified pathway.

Animals↗
PubMed1994

Diet and exercise in the treatment of NIDDM. The need for early emphasis.

OBJECTIVE: To investigate the effectiveness of an intensive diet and exercise program for controlling non-insulin-dependent diabetes mellitus (NIDDM) and reducing risk factors associated with macrovascular complications. RESEARCH DESIGN AND METHODS: Medical charts obtained from 4,587 participants in a lifestyle modification program were screened for patients with NIDDM. A total of 652 patients was identified, and their responses to the 3-week program were analyzed. RESULTS: Fasting glucose level was reduced from 10.0 to 8.45 mmol/l, and 71% of 197 subjects taking oral hypoglycemic agents and 39% of 212 taking insulin were able to discontinue their medication. Of the 243 not taking medication, 76% reduced their fasting glucose levels to < or = 7.84 mmol/l. Blood pressure was significantly reduced, and of the 319 initially taking antihypertension drugs, 34% had their medication discontinued. Serum total and low-density lipoprotein cholesterol were reduced by 22% and triglycerides by 33%. The ratio of total to high-density lipoprotein cholesterol was reduced by 13%. CONCLUSIONS: Lifestyle modification consisting of diet combined with aerobic exercise can be effective for controlling NIDDM and reducing risk factors associated with macrovascular complications in both men and women. The program was far more effective in controlling the disease in patients taking no medication or oral agents compared with patients taking insulin. These results stress the need for early emphasis on lifestyle modification in the treatment of NIDDM.

Adult↗
PubMed1993

Detection of intracellular cytokines by flow cytometry.

During the last years it has become increasingly clear that production of most cytokines is not confined to one cell type. Thus, a method to detect cytokines at the single cell level would be a helpful tool to study the contribution of different cells to cytokine production in heterogeneous cell populations. Recently, Sander et al. (1991) demonstrated that it is possible to detect intracellular cytokines by fixation with paraformaldehyde, permeabilization with saponin and subsequent indirect immunofluorescent staining using fluorescence microscopy. Here, we describe a modified method to increase the specific intracellular staining which enables us to detect IFN-gamma, IL-2 and IL-4 producing cells by single laser flow cytometry. The carboxylic ionophore monensin was used to interrupt intracellular transport processes leading to an accumulation of the cytokine in the Golgi complex. This resulting increase of the signal/noise ratio permitted us to detect weakly fluorescent cells such as IL-4 producing cells. While IL-4 was detected in approximately 1-3% of peripheral mononuclear cells from healthy donors, up to 30% of the cells produced IFN-gamma and nearly 50% IL-2 after phorbol ester and ionomycin stimulation. Microscopic and flow cytometric analysis showed a highly significant correlation. Using three-color flow cytometry it was possible to measure intracellular cytokines and cell surface markers simultaneously. Subpopulations of human T cells (e.g., CD4+ CD45R0-) producing a restricted cytokine pattern could be identified by cell surface staining and were characterized by their cytokine production. Consequently, there was no further need for cell sorting to determine cytokine producing subsets in heterogeneous cell populations. We have tested human T cell clones for intracellular cytokine production and found a high concordance to ELISA analysis of the supernatants. We conclude that detection of intracellular cytokines by flow cytometry is a rapid, easy and semiquantitative assay which may be used to study individual cells in heterogeneous populations as well as to screen homogeneous cells for their cytokine pattern. This method is particularly relevant in view of the accumulating evidence of the functional role that subsets of (T) cells may play in various diseases depending on the pattern of cytokines they produce.

Animals↗
PubMed1993

Effects of the protein phosphorylation inhibitor genistein on maturation of pig oocytes in vitro.

In vitro maturation of cumulus enclosed and denuded pig oocytes was reversibly inhibited by the protein kinase inhibitor genistein. The half-maximal effect on maturation was observed at 40 micrograms ml-1. Genistein inhibited total protein phosphorylation and synthesis with the same dose-response relationship (ED50: 40 micrograms ml-1). Protein phosphorylation and synthesis patterns were changed by effective concentrations of genistein. Pig oocytes were sensitive to genistein during the first 12 h of in vitro maturation. This genistein sensitive period corresponds closely with the period of sensitivity to the protein synthesis inhibitor cycloheximide. Whereas the inhibition of protein synthesis affects only nuclear membrane breakdown and not chromatin condensation, genistein inhibits both events. The results of these experiments suggest that protein phosphorylation and synthesis play major roles during pig oocyte maturation in vitro. It is concluded that genistein inhibited protein phosphorylation is a regulator of chromatin condensation, whereas both new protein synthesis and phosphorylation appear to be required for nuclear membrane disassembly. Caution about this second conclusion is, however, necessary because of the dual action of genistein on both protein phosphorylation and indirectly on protein synthesis.

Animals↗