Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The influence of the haematopoietic growth factor Flt-3 ligand (FL) on the incidence and function of donor major histocompatibility complex (MHC) class II+ cells in the lymphoid tissues of noncytoablated recipients of heart allografts and donor bone marrow (BM) cells was investigated. C3H (H2k) mice received a nonvascularized B10 (H2b) heart allograft in the dorsal ear pinna, followed by an i.v. infusion of 50 x 10(6) donor BM cells. They were given FL (10 microg/day i.p., x7 days), tacrolimus (2mg/kg/day i.p., x13 days) or both agents immediately following heart transplantation (HTx) and were killed 10 or 21 days later. Their BM cells were propagated in vitro in granulocyte macrophage colony stimulating factor (GM-CSF) and IL-4 for 5 days to promote the growth of dendritic cells (DC). Donor DC were identified by immunocytochemical staining. Spleens were harvested, and donor (IAb+) cells enumerated by immunohistochemical analysis. Donor MHC class II DNA was detected in spleens and cultured BM-derived cells by reverse transcriptase-polymerase chain reaction (RT-PCR). A striking increase in donor MHC class II+ cells was noted in both the spleen and BM of the BM + tacrolimus-treated group compared to either the BM alone, or BM + FL-treated groups. Addition of FL treatment to BM + tacrolimus led to a further increase in donor cells in spleen (three-fold at 10 days, and two-fold at 21 days). The increase in donor cells at 10 days was almost 140-fold compared to that with donor BM alone. PCR analysis at this time revealed enhanced donor DNA in the BM + FL + tacrolimus group compared to that in the BM + tacrolimus group. FL treatment augmented mixed leucocyte reactions (MLR) and cytotoxic T lymphocyte (CTL) activity of host spleen cells against donor alloantigens. These effects were reversed by tacrolimus administration. Histopathology of heart grafts from tacrolimus-treated animals at 10 and 21 days showed absence or substantial reduction in cellular infiltration, and the preservation of viable myocardium. By contrast, in untreated mice, or animals given BM or BM + FL alone, there was marked cellular infiltration, and features of accelerated rejection. Donor-derived DC could be propagated in vitro from the BM of heart transplant recipients given donor BM, especially from mice that also received tacrolimus +/- FL. At day 21, donor-derived cells could only be propagated from the BM + FL + tacrolimus-treated group. These findings show that numbers of donor antigen presenting cells (APC) or their progenitors can be markedly increased in conventionally immunosuppressed organ allograft recipients given donor BM + a potent haematopoietic and DC-growth promoting cytokine. Although withdrawal of systemic immunosuppression appears to allow exhibition of the potential allostimulatory activity of these donor APC leading to rejection, the model provides a useful basis for further evaluation of the persistence and manipulation of donor haematopoietic cells and in particular, donor-derived APC, on the outcome of organ transplantation.
...
PMID:Impact of Flt-3 ligand on donor-derived antigen presenting cells and alloimmune reactivity in heart graft recipients given adjuvant donor bone marrow. 1034 36

Activated vascular endothelial cells (ECs) express major histocompatibility complex (MHC) class II molecules in vitro and in vivo in acute and chronic allograft rejection. However, human ECs may be limited in their ability to effectively activate CD4(+) T cells, because they do not express members of the B7 family (CD80 and CD86) of costimulatory molecules. In this study, we show that ECs promote the full activation of CD4(+) T cells via trans-costimulatory interactions. By reverse transcriptase polymerase chain reaction, Western blot, and FACS((R)) analysis, we could not detect the expression of CD80 and CD86 on activated ECs and found minimal expression on purified CD4(+) T cells. In contrast, both CD80 and CD86 were expressed in allogeneic CD4(+) T cell-EC cocultures. Expression of CD86 peaked at early times between 12 and 24 h after coculture, whereas CD80 was not expressed until 72 h. Addition of anti-CD86 but not anti-CD80 monoclonal antibodies to cocultures inhibited IL-2 production and the proliferation of CD4(+) T cells to allogeneic donor human umbilical vein ECs (HUVECs), as well as to skin and lung microvascular ECs. Furthermore, we found that interferon gamma-activated ECs but not untreated ECs induced mRNA and cell surface expression of CD80 and CD86 on CD4(+) T cells, and these T cells were functional to provide a trans-costimulatory signal to autologous CD4(+) T cells. Blockade of MHC class II and lymphocyte function-associated antigen 3 but not other EC cell surface molecules on IFN-gamma-activated ECs inhibited the induction of CD86 on CD4(+) T cells. Transmigration of purified populations of monocytes across EC monolayers similarly resulted in the induction of functional CD86, but also induced the de novo expression of the cytokines interleukin (IL)-1alpha and IL-12. In addition, EC-modified monocytes supported enhanced proliferation of allogeneic and autologous CD4(+) T cells. Taken together, these data define the ability of the endothelium to modify CD4(+) T cells and monocytes for trans-costimulatory events. This unique function of the endothelium in alloimmune T cell activation has functional consequences for the direct and the indirect pathways of allorecognition.
...
PMID:Endothelial cells modify the costimulatory capacity of transmigrating leukocytes and promote CD28-mediated CD4(+) T cell alloactivation. 1044 26

Major histocompatibility complex (MHC) class II engagement by toxic shock syndrome toxin 1 (TSST-1) transduces signals leading to proinflammatory cytokine gene expression (tumor necrosis factor alpha [TNF-alpha]) in human monocytes. To study the proinflammatory role of MHC class II molecules expressed by bronchial epithelial cells (BEC), primary human BEC were isolated from surgical bronchial samples, expanded in vitro, and cultured in the presence or absence of gamma interferon (IFN-gamma) for 48 h. (125)I-TSST-1 binding to BEC pretreated with IFN-gamma was inhibited up to 97% by anti-MHC class II monoclonal antibody 3B12, indicating that in BEC also MHC class II molecules were targets for the staphylococcal exotoxin. As analyzed by a quantitative reverse transcriptase PCR, a 1-h stimulation of BEC with TSST-1 resulted in a vigorous expression of TNF-alpha and interleukin-8 (IL-8) genes. TNF-alpha and IL-8 expression was optimal in BEC pretreated with 50 IU of IFN-gamma/ml, whereas TSST-1 stimulation of BEC pretreated with 200 IU of IFN-gamma/ml failed to enhance either TNF-alpha or IL-8 transcripts. In a time course study, peak expression of TNF-alpha and IL-8 mRNA was reached 6 h after TSST-1 stimulation. These results demonstrate that bacterial superantigen TSST-1 binds to MHC molecules on BEC and induces TNF-alpha and IL-8 gene expression upon engagement of MHC class II molecules on BEC, thus contributing to the perpetuation of bronchial mucosa inflammation via chemokine or cytokine gene expression.
...
PMID:Induction of tumor necrosis factor alpha and interleukin-8 gene expression in bronchial epithelial cells by toxic shock syndrome toxin 1. 1060 77

Dendritic cells (DCs) are essential for the presentation of antigens in the primary immune response. To examine the generation of DCs from hemopoietic stem cells in the bone marrow (BM), lineage-negative (Lin-)/CD71- bone marrow cells (BMCs) from C57BL/6 mice were separated into major histocompatibility complex (MHC) class Ihigh/ c-kit(low) and MHC class Ihigh/c-kit(low)(phenotypically c-kit-negative, but c-kit message only detected by reverse transcriptase-polymerase chain reaction) populations. A large number of cells with the morphological, phenotypical, and functional characteristics of DCs was generated from both c-kit(low) and c-kit(low) populations when cultured with a combination of cytokines (GM-CSF, tumor necrosis factor-a [TNF-a], interleukin 7 [IL-7], IL-3, stem cell factor [SCF], and flt3 ligand); the cytokine combination studies revealed that SCF and IL-3 in addition to GM-CSF and TNF-a are essential for DCs to be generated from these primitive populations. To our surprise most (>80%) generated cells expressed high levels of DC surface markers such as DEC205 and MHC class II, and they were potent stimulators in the primary allogeneic T cell activation. The development of DCs from c-kit(<low) cells was slower than that from c-kit(low) cells. These results indicate that c-kit(<low) cells are more primitive than c-kit(low) cells, although both c-kit*(low) cells and c-kit(<low) cells can differentiate into DCs. It should be noted that the combination of these cytokines selectively induces DCs from both c-kit(<low) and c-kit(low) cells in vitro, suggesting that the ex vivo expansion of DCs using these primitive cells would be applicable to immunotherapy.
...
PMID:Development of mouse dendritic cells from lineage-negative c-kit(low) pluripotent hemopoietic stem cells in vitro. 1066 72

Macrophage-colony-stimulating factor (M-CSF) regulates the survival, proliferation and differentiation of the mononuclear phagocyte lineage. Osteopetrotic (op/op) mice defective in producing functional M-CSF were used in order to investigate the role of M-CSF on the development of microglia and brain macrophages and the expression of scavenger receptor (SR). Adult op/op and littermate mice at 10-47 weeks of age were investigated by immunohistochemistry with a panel of monoclonal antibodies (F4/80, Mac-1, anti-major histocompatibility complex (MHC) class II and anti-SR), electron microscopy and reverse transcriptase-polymerase chain reaction (RT-PCR). Microglia were weakly immunolabeled with F4/80 and Mac-1 in op/op and littermate mice, but the number of microglia in op/op mice was reduced in the cerebrum, cerebellum and brainstem compared with that of normal littermates. The numbers of Mac-1-positive microglia in op/op mice was 39% (pons) and 30% (cerebellar cortex) lower than that in normal littermates (P<0.05). In addition, the microglia cell processes in op/op mice were often shorter than those in control mice. In op/op and littermate mice, both MHC class II and SR were present in perivascular cells and macrophages of the leptomeninx and choroid plexus. Ultrastructurally, perivascular cells appeared to be immature, since their cytoplasm was narrow and contained few inclusion bodies compared with those of control mice. Reverse transcriptase-polymerase chain reaction showed a weak expression for SR mRNA in the brains of op/op mice as well as littermate mice. These results indicate that microglia are partly dependent on M-CSF for their proliferation and differentiation and that M-CSF has no significant effect on the expression of SR in the physiological brain. The study also suggests that M-CSF affects the maturation of perivascular cells at the ultrastructural level.
...
PMID:Effects of macrophage-colony-stimulating factor deficiency on the maturation of microglia and brain macrophages and on their expression of scavenger receptor. 1093 50

Experimental autoimmune encephalomyelitis (EAE) is a demyelinating disease of the central nervous system (CNS) that serves as a model for multiple sclerosis (MS) in humans. In mice, EAE is mediated by Th1 type CD4(+) T cells specific for various myelin proteins which migrate from the periphery to the CNS. Removal or blocking of CD4(+) cells before or shortly after disease induction was shown to prevent disease onset and/or disease progression but also results in general immune suppression. Most treatment regimens for autoimmune diseases currently rely on general suppression of the T-cell compartment most commonly by steroids. In this paper, an experimental, gene therapy-based model is presented in which susceptible mice are made resistant to EAE induction by specifically down-regulating an autoreactive T-cell population. By using a retroviral gene transfer protocol, normal B cells were genetically modified to constitutively express the SJL-specific proteolipid (PLP) encephalitogenic determinant and then adoptively transferred into syngeneic hosts. To ensure appropriate presentation of the exogenous encephalitogenic peptide in association with MHC class II, the encephalitogenic sequence was fused to a lysosomal targeting sequence. Adoptive transfer of syngeneic B cells expressing the PLP encephalitogenic determinant into normal, naive, genetically susceptible mice induced PLP-specific unresponsiveness and completely protected the majority (62% and 83% using an intermediate and a high titer retroviral vector, respectively) of the animals from EAE induction. The remaining animals had a delayed disease onset and/or lower disease severity. All protected mice expressed the exogenous gene in the spleen as detected by reverse transcriptase-polymerase chain reaction.
...
PMID:A gene therapy approach for treating T-cell-mediated autoimmune diseases. 1115 13

Gamma interferon (IFN-gamma)-induced endothelial cells actively participate in initiating immune responses by interacting with CD4(+) T cells via class II major histocompatibility complex (MHC) surface glycoproteins. Previously, Porphyromonas gingivalis membrane vesicles were shown to selectively inhibit IFN-gamma-induced surface expression of HLA-DR molecules by human umbilical cord vascular endothelial cells. In this study, we demonstrated an absence of HLA-DR alpha mRNA from IFN-gamma-induced cells in the presence of P. gingivalis membrane vesicles by using reverse transcriptase-PCR and Southern blotting. Vesicles also prevented transcription of the gene encoding class II transactivator, a transactivator protein required for IFN-gamma-induced expression of MHC class II genes. In addition, the effects of vesicles on IFN-gamma signal transduction involving Jak and Stat proteins were characterized by using immunoprecipitation and Western blot analyses. Jak1 and Jak2 proteins could not be detected in endothelial cells treated with membrane vesicles. Consequently, IFN-gamma-induced phosphorylation of Jak1, Jak2, and Stat1 alpha proteins was prevented. The class II-inhibitory effect of the membrane vesicles could be eliminated by heating vesicles at 100 degrees C for 30 min or by treating them with a cysteine proteinase inhibitor. This indicates that the cysteine proteinases were most likely responsible for the absence of Jak proteins observed in vesicle-treated cells. The observed increased binding of radiolabeled IFN-gamma to vesicle-treated cells suggests that vesicles may also modulate the IFN-gamma interactions with the cell surface. However, no evidence was obtained demonstrating that vesicles affected the expression of IFN-gamma receptors. Thus, P. gingivalis membrane vesicles apparently inhibited IFN-gamma-induced MHC class II by disrupting the IFN-gamma signaling transduction pathway. Vesicle-inhibited class II expression also occurred in other IFN-gamma-inducible cells. This suggested that the ability of P. gingivalis membrane vesicles to modulate antigen presentation by key cells may be an important mechanism used by this particular bacterium to escape immunosurveillance, thereby favoring its colonization and invasion of host tissues.
...
PMID:Modulation of gamma interferon-induced major histocompatibility complex class II gene expression by Porphyromonas gingivalis membrane vesicles. 1185 99

Recent studies on dendritic cell (DC)-associated genes have been performed using monocyte-derived DCs (MoDCs) in different maturation stages. In our approach, to uncover the novel DC-associated genes and their expression profiles among the different DC subsets, we constructed a subtracted DC-cDNA library from CD1a(+), CD14(+), and CD11c(-) DCs by subtracting the genes shared with T cells, B cells, and monocytes, and we then screened the libraries with the aid of microarray technique. The genes showing remarkable specificity to DCs in the microarray analysis were selected and confirmed by semiquantitative reverse transcriptase-polymerase chain reaction. Our investigations revealed the following: (1) Genes highly expressed in myeloid DCs are those involved in antigen uptake/processing/presentation, cell metamorphosis, or chemotaxis. (2) Most of the genes previously identified in MoDCs, such as TARC, ferritin L-chain, lysosomal acid lipase, alpha- and beta-tubulin, osteopontin (Eta-1), and others, are not markedly expressed in CD11c(-) DCs regardless of their maturation status. On the other hand, specific transcription factors and MHC class II molecules, such as interferon regulatory factor-4 (IRF4) and HLA-DR, are similarly expressed in both DC subsets. (3) CD14(+) DCs retain unique features of tissue DCs, as evidenced by the gene expression profile of "no CCR7 but more CCR1" and "no TARC but abundant MCP1 and Eta-1." (4) The genes for immunoglobulin (Ig) superfamily Z39Ig, CD20-like precursor, glycoprotein NMB (GPNMB), transforming growth factorbeta (TGF-beta)-induced protein (TGFBI), myeloid DAP12-associated lectin (MDL-1), and 6 novel genes are newly identified as being associated with the phenotypic expression of the DC subsets. These identifications provide important molecular information for further functional studies of the DC subsets.
...
PMID:Identification of the genes differentially expressed in human dendritic cell subsets by cDNA subtraction and microarray analysis. 1217 96

Polymorphism in the upstream regulatory region (URR) of the MHC class II DQA1 gene defines 10 different alleles named QAP (DQA1 promoter). In vitro studies have suggested that allelic polymorphism in the HLA-DQA promoter region may result in differences in HLA-DQA1 gene expression. In the present study, we used real-time reverse transcriptase-polymerase chain reaction (RT-PCR) to quantify differences in HLA-DQA1 gene expression. After the isolation of total mRNA, reverse transcription into cDNA was carried out using random hexamer priming and moloney murine leukaemia virus (MMLV) reverse transcriptase. Quantification of DQA1 mRNA species using a set of six group-specific primer pairs for the detection of HLA-DQA1*01, *02, *03, *04, *05 and *06 was carried out on an ABI PRISM GeneAmp 7700 Sequence Detection System (Perkin Elmer, Foster City, CA) with real-time detection and quantification taking advantage of the fluorescence TaqMan technology (Perkin Elmer, Foster City, CA). Normalization of cDNA templates was achieved by glyceraldehyde-3-phosphate dehydrogenase (GAPDH) quantification. In addition, the total amount of mRNA produced by HLA-DQA1 and HLA-DRA1 expression was quantified for comparison. Subsequently, this approach was validated using Raji and HUT-78 cell lines and tested with peripheral mononuclear cells (PBMC) of 45 samples taken from healthy volunteers. The sensitivity was determined with > or = 10(2) copies. Comparison of the allele-specific DQA1 expression with the total expression of DQA1 and DRA1 mRNA indicated that DQA1*04 expression was increased compared with the expression of other alleles of the DQA1 gene. Thus, allele-specific quantification of DQA1 gene products could be achieved by real-time RT-PCR suitable for the analysis of differential expression of DQA1 mRNAs in homozygote and heterozygote combinations.
...
PMID:Relative quantification of HLA-DRA1 and -DQA1 expression by real-time reverse transcriptase-polymerase chain reaction (RT-PCR). 1264 83

Psoriasis is a chronic inflammatory skin disorder characterized by accumulation of Th1-type T cells and neutrophils, regenerative keratinocyte proliferation and differentiation, and enhanced epidermal production of antimicrobial peptides. The underlying cause is unknown, but there are some similarities with the immunologic defense program against bacteria. Development of psoriasiform skin lesions has been reported after administration of granulocyte colony-stimulating factor (G-CSF), a cytokine induced in monocytes by bacterial antigens. To further investigate the relation between this type of cytokine-induced dermatitis and psoriasis, we analyzed the cutaneous cytokine profile [tumor necrosis factor-alpha (TNF-alpha), interferon-gamma, transforming growth factor-beta1 (TGF-beta1), interleukin-10 (IL-10), IL-12p35 and p40, and IL-8] and expression of markers of epidermal activation [Ki-67, cytokeratin-16, major histocompatibility complex (MHC) class II, intercellular adhesion molecule-1 (ICAM-1)] in a patient who developed G-CSF-induced psoriasiform dermatitis by using quantitative real-time reverse transcriptase-polymerase chain reaction and immunohistology. The histologic picture resembled psoriasis with regard to epidermal hyperparakeratosis and the accumulation of lymphocytes in the upper corium. CD8(+) T cells were found to infiltrate the epidermis which was associated with an aberrant expression of Ki-67, cytokeratin-16, MHC class II, and ICAM-1 on adjacent keratinocytes. As compared to normal skin (n = 7), there was an increased expression of TNF-alpha, IL-12p40, and IL-8, a decreased expression of TGF-beta1, and a lack of IL-10, similar to the findings in active psoriasis (n = 8). Therefore, G-CSF may cause a lymphocytic dermatitis that, similar to psoriasis, is characterized by a pro-inflammatory Th1-type cytokine milieu and an epidermal phenotype indicative of aberrant maturation and acquisition of non-professional immune functions.
...
PMID:Granulocyte colony-stimulating-factor-induced psoriasiform dermatitis resembles psoriasis with regard to abnormal cytokine expression and epidermal activation. 1518 19


<< Previous 1 2 3 4 Next >>

---