Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The expression of the cytokine genes in human spleen was studied using reverse transcriptase-polymerase chain reaction (RT-PCR) method capable of detecting low levels of mRNA. Total RNA was prepared from human spleen by acid guanidinium thiocyanate-phenol-chloroform (AGPC) method. cDNA was synthesized by M-MLV RTase using oligo (dT)16 primer, and amplified using the oligonucleotide primers specific for IL-1 alpha, IL-1 beta, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, TNF-alpha, IFN-alpha, IFN-beta and IFN-gamma by PCR method. Although IL-1 beta, IL-4, IL-5, IL-6, IL-7, IL-8, TNF-alpha, IFN-alpha and IFN-gamma mRNA were detected in all the samples tested, IL-3 and IFN-beta mRNA was not detected at all. These results suggest that many kinds of cytokines may be produced constitutionally in human spleen, and its pattern of cytokine production was similar to that in mice.
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PMID:[Expression of cytokine messenger RNA in human spleen]. 783 9

While the role of cytokines in mediating injury during hind limb skeletal muscle ischemia followed by reperfusion has recently been described, the role of cytokines in myocardial infarction and ischemia/reperfusion have remained relatively unexplored. We hypothesize that cytokines play an important role in the regulation of postischemic myocardial inflammation. This study reports the temporal sequence of proinflammatory cytokine gene expression in postischemic/reperfused myocardium and localizes interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha)-protein by immunostaining. Rats were subjected to either permanent left anterior descending (LAD) occlusion or to 35 minutes of LAD occlusion followed by reperfusion and sacrificed up to 7 days later. Rat-specific oligonucleotide probes were used to semiquantitatively assess the relative expression of mRNA for TNF-alpha, IL-1 beta, IL-2, IL-6, interferon-gamma (IFN-gamma), and transforming growth factor-beta 1 (TGF-beta 1) utilizing the reverse transcriptase-polymerase chain reaction amplification technique. Increased cardiac mRNA levels for all cytokines except IL-6 and IFN-gamma were measurable within 15 to 30 minutes of LAD occlusion and increased levels were generally sustained for 3 hours. During early reperfusion, mRNA levels for IL-6 and TGF-beta 1 were significantly reduced compared with permanent LAD occlusion. In both groups, cytokine mRNA levels all returned to baseline levels at 24 hours, while IL-1 beta, TNF-alpha, and TGF-beta 1 mRNA levels again rose significantly at 7 days only in animals with permanent LAD occlusion. Immunostaining for IL-1 beta and TNF-alpha protein revealed two patterns of reactivity: 1) microvascular staining for both IL-1 beta and TNF-alpha protein only in postischemic reperfused myocardium in early post-reperfusion time points; and 2) staining of infiltrating macrophages in healing infarct zones which was most prominent at 7 days after permanent LAD occlusion. These results provide evidence for local expression of cytokine mRNA in postischemic myocardium and suggest that regulation of local cytokine release is altered during the postischemic period.
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PMID:Cytokine mRNA expression in postischemic/reperfused myocardium. 785 52

We noted previously that ischemic acute tubular necrosis (ATN) induces local expression of MHC products in renal epithelium. The present investigations were conducted to establish the role of IFN-gamma in the regulation of MHC antigen expression in ATN and to explore the changes in cytokine and growth factor expression induced by ischemic renal injury. We produced unilateral ischemic ATN in mice by clamping the left renal pedicle. MHC class I and II steady state mRNA induction was assessed by northern blot analysis, and MHC product was quantified by the extent of binding of radiolabeled monoclonals to tissue homogenates. The steady state mRNA levels for IFN-gamma, IL-2, IL-10, and granulocyte-macrophage CSF were assessed by reverse transcriptase polymerase chain reaction and the levels for transforming growth factor-beta 1 and prepro-epidermal growth factor (ppEGF) were assessed by Northern blot analysis. In the injured kidneys, steady state mRNA levels for IFN-gamma, IL-2, IL-10, granulocyte-macrophage CSF, and transforming growth factor beta-1 were increased, whereas ppEGF mRNA was markedly decreased. The MHC expression was inhibited by treatment of mice with an anti-IFN-gamma mAb (R4-6A2). Murine EGF, administered in an attempt to accelerate recovery, did not reduce the cytokine and MHC changes. These data indicate that ischemic injury, and possibly other forms of injury, triggers a complex circuit of proinflammatory cytokines. This "injury response" could be relevant to clinical renal transplants, where ATN is associated with poor graft outcome.
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PMID:Ischemic acute tubular necrosis induces an extensive local cytokine response. Evidence for induction of interferon-gamma, transforming growth factor-beta 1, granulocyte-macrophage colony-stimulating factor, interleukin-2, and interleukin-10. 787 62

Antigen presentation by endogenous glial cells is postulated to regulate reactivity of immune cells that gain entry into the CNS. We have previously observed, using a mixed lymphocyte reaction (MLR) system, that adult human-derived microglia can function as antigen-presenting cells (APC) for immediately ex vivo CD4+ T cells in a primary MLR (1 degree MLR) whereas astrocytes could not. We have now found that fetal human astrocytes can support CD4+ T cell proliferation in the presence of exogenous human recombinant (r) IL-2, and that astrocytes can support the continued proliferation of CD4+ T cells previously sensitized to sister astrocyte cultures in a secondary MLR. Additionally, adult human microglia, seeded into the nonpriming astrocyte: CD4+ T cell cocultures at non-T cell-stimulatory concentrations of 1000-5000 microglial cells per well, could reverse the inability of astrocytes to present antigen in the primary MLR. To examine the cellular basis for the inability of human astrocytes to function as APCs in the primary MLR, astrocyte- and microglial-enriched populations were established from human embryonic and adult brain, respectively, and analyzed for their ability to synthesize cytokines potentially relevant as accessory signals in the MLR. Microglia had transcript as determined by the reverse transcriptase-polymerase chain reaction (RT-PCR) and protein as determined by bioassay for IL-1 alpha, IL-6, and TNF alpha. Human fetal astrocytes had transcript for IL-6 but not for IL-1 alpha or TNF alpha under basal culture conditions and following IFN gamma stimulation. The addition of human rIL-1 from 1-50 U/ml could reverse the inability of astrocytes to present antigen in the primary MLR. These studies demonstrate that although in vitro highly enriched cultures of astrocytes absent of microglia cannot present antigen to immediately ex vivo blood-derived CD4+ T cells in the MLR, in situ, with the cooperative help of microglia-derived cytokines or accessory surface molecules, astrocytes may function as central nervous system APCs.
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PMID:Antigen presentation by human fetal astrocytes with the cooperative effect of microglia or the microglial-derived cytokine IL-1. 789 Nov 40

By using superantigens, we have found previously that keratinocytes activated by IFN-gamma could serve as accessory cells, providing costimulatory signals needed to induce T cell proliferation. Here, we compared the profile of cytokines produced by T cells stimulated in the presence of activated keratinocytes with the response seen using professional APCs. When keratinocytes are used as accessory cells there is a specific defect in T cell IFN-gamma production, whereas IL-2 and IL-4 are induced at levels comparable with those seen when professional APCs are used as accessory cells. Because keratinocytes express BB-1, a CD28-ligand distinct from B7-1 or B7-2 (which are found on professional APCs), we examined the possibility that the defect in IFN-gamma production might be a result of nonproductive CD28 engagement. However, even when the CD28 pathway is directly activated by a stimulatory mAb, there is no induction of IFN-gamma production in keratinocyte-supported cultures. In these same cultures IL-2 production is increased 10-fold, thus demonstrating a specific deficiency in the induction of IFN-gamma rather than a failure to respond to CD28 stimulation. Analysis by reverse transcriptase-PCR and ELISA for the inducible p40 chain of IL-12 reveals that keratinocytes produce little if any messenger RNA and no protein for IL-12 p40 compared with professional APCs. Addition of rIL-12 to keratinocyte-supported cultures restores IFN-gamma levels to those seen when professional APCs are present. Finally, when T cells are restimulated and analyzed at later time points (10 to 14 days) we find a refinement in cytokine profiles: T cells stimulated in the presence of professional APCs produced the Th1 cytokines IL-2 and IFN-gamma, whereas T cells stimulated in the presence of activated keratinocytes produced only the Th2 cytokine IL-4. The specific ability of keratinocytes to induce a Th2 response seems most closely linked to their absence of IL-12 production, and may be important in the maintenance of peripheral tolerance to self-Ags or in the immune response to exogenous Ags, pathogens, or haptens encountered in skin.
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PMID:Keratinocyte-derived T cell costimulation induces preferential production of IL-2 and IL-4 but not IFN-gamma. 791 Jun 19

The major purpose of this study was to elucidate Th1 [interferon (IFN)-gamma and interleukin (IL)-2] and Th2 (IL-4, IL-5 and IL-6) cytokine-producing CD3+ T cells in salivary glands, which are the major mucosal effector tissues in the oral region. Thus, CD3+ T cells were isolated from salivary gland-associated tissues (SGAT) which consist of the submandibular gland (SMG: approximately 46%), the periglandular lymph node (PGLN: approximately 72%), and the cervical lymph node (CLN: approximately 90%). When SMG CD3+ T cells were examined by Th1 and Th2 cytokine-specific ELISPOT and reverse transcriptase-polymerase chain reaction assay, high levels of both cytokine-specific spot-forming cells (SFC) and mRNA for IFN-gamma, and for IL-5 and IL-6 were noted as representative Th1 or Th2 cytokines, respectively. Following stimulation with concanavalin A (Con A), SMG CD3+ T cells expressed mRNA and produced lymphokines for an array of Th1 (IFN-gamma and IL-2) and Th2 (IL-4, IL-5 and IL-6) cytokines. In comparison to the SMG CD3+ T cells, PGLN and CLN contain lower numbers of IFN-gamma-, IL-5 and IL-6-producing T cells. When these two tissues were compared, PGLN CD3+ T cells contained higher numbers of cytokine-secreting cells than CLN. Further, IL-2 and IL-4 SFC and mRNA were also noted in addition to IFN-gamma, IL-5 and IL-6 after Con A activation. These findings showed that CD3+ T cells in SGAT, especially the SMG, are programmed to produce IFN-gamma, and IL-5 and IL-6 as Th1 and Th2 cytokines, respectively in vivo, although these cells are capable of producing other Th1 and Th2 cytokines after receiving appropriate T cell activation signals.
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PMID:Characterization of cytokine-producing cells in mucosal effector sites: CD3+ T cells of Th1 and Th2 type in salivary gland-associated tissues. 795 57

We have used the potent mucosal immunogen cholera toxin (CT) to assess antigen-specific CD4+ T-cell responses, including Th1- and Th2-type cells in mucosa-associated tissues, e.g. Peyer's patches (PP), and systemic tissue, e.g. spleen (SP), for their regulatory role in the induction of CT-specific B-cell antibody responses in the gastrointestinal (GI) tract as well as in systemic sites. The CT was given by either oral or intravenous (i.v.) routes and the mice orally immunized with CT exhibited brisk IgA anti-CT antibody responses in faecal extracts and elevated IgG anti-CT antibody responses in serum. Further, significant IgA anti-CT spot-forming cells (SFCs) were seen in lamina propria lymphocytes (LPLs) from mice orally immunized with CT. In contrast, i.v. immunization with CT induced IgM and IgG anti-CT SFC responses in SP, and serum anti-CT antibodies of these two isotypes; no anti-CT responses were induced in the GI tract after immunization by this route. The CD4+ T cells isolated from PP and SP of mice orally immunized with CT were stimulated in vitro with CT-B-coated latex microspheres for 1-6 days, and the induction of IL-2 and interferon gamma (IFN-gamma) (Th1-type) or IL-4 and IL-5 (Th2-type) producing SFCs were analysed by a cytokine-specific ELISPOT and cytokine-specific mRNA was detected by reverse transcriptase (RT)-PCR assays.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Helper Th1 and Th2 cell responses following mucosal or systemic immunization with cholera toxin. 797 32

Aberrant elevation of serum IgA and induction of murine IgA nephropathy following dietary exposure to the naturally occurring trichothecene vomitoxin (VT or deoxynivalenol) may involve dysregulation of cytokine production at the T cell level. EL4.IL-2 (EL-4), a cloned thymoma that produces interleukins (IL)-2, 4, 5, and 6, was used as a T cell model to investigate the in vitro effects of VT on interleukin production and gene expression. When supernatants of cells stimulated with phorbol 12-myristate 13-acetate (PMA) were assessed by enzyme-linked immunosorbent assay, IL-2, 4, and 5 were increased in the presence of 50 and/or 100 ng/ml VT for 2 and/or 8 days of culture. IL-2, 5, and 6 were also significantly elevated in the presence of 10-100 ng/ml of cycloheximide (CHX), another protein synthesis inhibitor, after 8 days of culture. As demonstrated by Northern analysis, VT at the levels between 50 and 100 ng/ml superinduced IL-2, 4, 5, and 6 mRNAs in PMA-stimulated EL-4 cells during a 24 hr culture period. Similar effects in PMA-treated samples were observed for CHX at 50, 100, 250, 1000, and 10000 ng/ml. mRNA levels for both IL-4 and IL-5, but not IL-2 and IL-6, were increased in unstimulated EL-4 cultures exposed to 50 and 100 ng/ml VT for 48 hr when analyzed by reverse transcriptase-polymerase chain reaction. Using [3H]leucine incorporation as a measurement of protein synthesis, IC50s for VT and CHX were estimated to be 280 and 55 ng/ml, respectively. This study indicates that VT as well as CHX could increase production of several interleukins in the EL-4 model even when present at concentrations that partially inhibited protein synthesis, whereas IL mRNA superinduction occurred across a broader range of concentrations that included maximal protein synthesis inhibition.
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PMID:Elevated gene expression and production of interleukins 2, 4, 5, and 6 during exposure to vomitoxin (deoxynivalenol) and cycloheximide in the EL-4 thymoma. 804 72

The immune response to an allograft is regulated by cytokines produced by cells infiltrating the allograft. However, the immunopathogenesis of allograft rejection is not completely understood. To investigate the role of cytokines after clinical heart transplantation, we analysed the expression of cytokine genes in sequentially taken endomyocardial biopsies (EMB) by using the reverse transcriptase-polymerase chain reaction (RT-PCR). We analysed 44 EMB from 11 recipients: 21 EMB before or during rejection, and 23 EMB without histological evidence of acute rejection. A strong correlation was found between IL-2 gene expression and histologically proved rejection (16/21 versus 1/23 without rejection, P < 0.001; chi 2 test). Also, expression of IL-4 and IL-6 genes was more often found in EMB during rejection than in EMB without signs of rejection (IL-4, 62% versus 35%; and IL-6, 81% versus 39%, respectively). No relation with rejection or with immunological quiescence was observed for the presence of IL-10 gene transcripts. IL-10, but also IL-6 mRNA were detectable in donor heart tissue before transplantation (9/10). In contrast, IL-2 and IL-4 gene transcripts were absent in these samples. These differences could not be explained by the presence or absence of T cells, since the gene for the constant region of the beta-chain (C beta) of the T cell receptor (TCR) not only was expressed in post-transplant EMB but also in pre-transplant donor heart tissue. Our results provide strong evidence that the immunoregulatory cytokines IL-2, IL-4 and IL-6 are important local regulators in the graft during acute rejection. The role of IL-10 in the immunologic response to the transplanted organ needs further investigation.
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PMID:Cytokine mRNA expression in endomyocardial biopsies during acute rejection from human heart transplants. 805 Jan 79

Efficient immunologic tolerance, defined as antigen-specific unresponsiveness, can be peripherally induced by the i.v. injection of syngeneic splenocytes coupled with antigen using ethylene carbodiimide (ECDI). We have previously reported that unresponsiveness induced via i.v. injection of syngeneic splenocytes coupled with intact, UV-inactivated Theiler's murine encephalomyelitis virus (TMEV-SP) resulted in 'split tolerance'. Both virus-specific delayed-type hypersensitivity and IgG2a levels were inhibited, whereas IgG1 levels were increased when compared with sham tolerized controls. In the present report we demonstrate that tolerance induced by i.v. injection of TMEV-coupled splenocytes resulted in antigen-specific inhibition of T cell proliferation, as well as IL-2 and IFN-gamma production in response to both whole TMEV and the immunodominant viral epitope. Additionally, tolerance induction resulted in abrogation of Th1-derived [IL-2, IFN-gamma and LT/tumor necrosis factor-beta (TNF-beta)] cytokine mRNA expression in response to in vitro stimulation with UV-inactivated TMEV as determined by reverse transcriptase polymerase chain reaction. In contrast, expression of Th2-derived (IL-4, IL-6 and IL-10) cytokine mRNA was not affected in tolerized mice. Tolerance functioned directly at the level of CD4+ Th1 cells at both the induction and effector limbs as depletion of CD8+ T cells both prior to in vivo tolerization or in vitro culture had no effect on inhibition of Th1-specific responses. The mechanism of in vivo tolerance induction appeared to be anergy of CD4+ Th1 cells since IL-2, IFN-gamma and LT/TNF-beta mRNA expression as well as virus-specific proliferative responses could be restored by addition of rIL-2 to in vitro cultures of tolerant, CD4+ Th1 populations. These results suggest that in vivo 'split tolerance' induced by i.v. injection of ECDI-fixed, antigen-coupled splenocytes involves anergy of TMEV-specific, CD4+ Th1 lymphocytes and concomitant priming of Th2 cells. The induction of antigen-specific, in vivo anergy has important implications in the design of therapeutic strategies for immunopathologic diseases mediated by Th1 lymphocytes, especially T cell-mediated autoimmune disorders.
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PMID:Anergy in vivo: down-regulation of antigen-specific CD4+ Th1 but not Th2 cytokine responses. 808 Aug 42


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