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

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Query: EC:3.5.4.4 (adenosine deaminase)
5,136 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Three established human T-cell lines, HPB-MLT, HPB-ALL and PEER, were characterized and tested for their sensitivity to deoxyadenosine (dAdo) plus deoxycoformycin (dCoF). Phenotypic characterizations showed that all three cell lines had receptors for peanut agglutinin (PNA) and soybean agglutinin (SBA) while HPB-MLT and HPB-ALL, but not PEER, expressed the cortical thymocyte-specific marker, CD1. The majority of HPB-MLT cells (88%) expressed only CD4 but not CD8 antigen while most HPB-ALL cells (81%) co-expressed CD8 and CD4 antigens. PEER cells were negative for both CD8 and CD4. These three T cell lines showed differential sensitivity to dAdo plus dCoF in consequent tests. dAdo or dAdo plus dCoF (1 microM) had no effect on the growth, or DNA and RNA synthesis of HPB-MLT cells while the combination of dAdo and dCoF partially inhibited cellular growth and DNA and RNA synthesis of HPB-ALL cells. Further, the growth and DNA and RNA synthesis of PEER cells were strongly inhibited by the combination of dAdo and dCoF. This high sensitivity to dAdo plus dCoF reflected an immature phenotype of PEER cells despite its expression of CD3. Flow cytometric analysis of PEER cells demonstrated disappearance of the G2/M phase cells from the cell cycle after treatment with dAdo plus dCoF. Measurements of adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) activities in all three cell lines, however, did not establish correlations between purine metabolizing enzyme activities and the differential sensitivities to dAdo plus dCoF. In sum, we report here three T-cell lines of different phenotypes that displayed significantly different sensitivities to dAdo plus dCoF which may facilitate investigations on the mechanisms of ADA deficiency.
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PMID:Characterization of three T-lymphoid cell lines with distinct sensitivities to deoxyadenosine plus deoxycoformycin. 137 28

Evidence of an acquired T cell-specific deficiency distinct from acquired immunodeficiency syndrome (AIDS) in a 63-yr-old Japanese female is provided. Recently, this patients suffered from primary invasive pulmonary aspergillosis. Skin tests to purified protein derivative of tuberculin (PPD) and Aspergillus antigens were negative. Upon admission to our hospital, her lymphocytes were exclusively unresponsive to T cell mitogens (concanavalin A, phytohemagglutinin, and OKT 3). The level of cells defined by monoclonal antibodies (CD1, CD2, CD3, CD4, WT31, and CD5) was less than 3%. In contrast, no decrease in the number of red blood cells, platelets, neutrophils or B cells was apparent. Five years ago, the patient had a normal white blood cell and lymphocyte count. However, over the following 4 yr, she developed lymphopenia. With medication, her pulmonary disease recovered, while lymphopenia still continued. The levels of immunoglobulins, complements and enzyme activities (adenosine deaminase and purine nucleoside phosphorylase) were normal. Moreover, several tests for HIV (ELISA and Western bolt) were negative suggesting that the T cell-specific deficiency was not a congenital immunodeficiency or AIDS but rather a new type of acquired immunodeficiency.
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PMID:Acquired T cell specific deficiency other than acquired immunodeficiency syndrome (AIDS). 156 29

The congenital absence of adenosine deaminase in humans results in severe combined immunodeficiency. To clarify the process whereby thymocytes are destroyed in the absence of adenosine deaminase activity, we induced a parallel condition in mice through the injection of an inhibitor of adenosine deaminase, deoxycoformycin. We have observed that deoxycoformycin, in addition to maintaining high levels of dATP in thymocytes, blocks the progression of thymocyte differentiation at two points. As a result of the first block, the cortex is depleted of immature cortical thymocytes while CD4+CD8+ thymocytes with functionally rearranged T-cell receptors survive. As a result of the second block, the CD4+CD8+ thymocytes are prevented from further differentiation to mature CD4+CD8- or CD4-CD8+ T lymphocytes and accumulate at the corticomedullar junction and in the medulla. These observations suggest that the maintenance of dNTP pools by adenosine deaminase is critical to at least two stages of thymocyte differentiation.
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PMID:Adenosine deaminase and thymocyte maturation. 182 94

The effect of polyethylene glycol-adenosine deaminase (PEG-ADA) therapy on biochemical, immunological and clinical abnormalities in an ADA-deficit child with severe combined immunodeficiency has been studied. Following PEG-ADA therapy, total lymphocytes, lymphocyte subsets (CD3, CD4 and CD8) and the response of lymphocytes to non specific mitogens increase significantly. The improvement of immunological functions is closely related to a decrease of erythrocyte deoxyadenosine triphosphate (dATP) concentrations. This study shows that PEG-ADA therapy is sufficiently effective to reduce and to maintain erythrocyte dATP levels at values compatible with normal immune functions. PEG-ADA represents an important progress for the treatment of ADA deficiency associated with severe combined immunodeficiency disease.
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PMID:[Polyethylene glycol-adenosine deaminase: a new adenosine deaminase deficiency therapy. Value of deoxyadenosine triphosphate determination for therapeutic monitoring]. 194 9

Plasma concentrations of the two isoenzymes of adenosine deaminase (ADA, E.C. 3.5.4.4), adenosine deaminase1 (ADA1) and adenosine deaminase2 (ADA2), were measured in a cohort of ambulatory patients infected with the human immunodeficiency virus (HIV) and controls. A sensitive isoenzyme-specific radioisotopic assay system was developed for these studies. Among 22 HIV-infected patients, plasma ADA2 was significantly elevated as compared with 16 control subjects (p less than 0.01) and 6 uninfected subjects having a risk factor for HIV infection (p less than 0.01). Plasma ADA2 was not associated with the stage of disease as defined by clinical status (p greater than 0.05) or helper (CD4) lymphocyte count (p greater than 0.05). Available evidence suggests that elevated plasma ADA2 could be a useful surrogate marker for HIV infection that occurs early in the disease process.
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PMID:Plasma adenosine deaminase2: a marker for human immunodeficiency virus infection. 198 54

To clarify the immunological aspect of tuberculosis, we investigated serum adenosine deaminase (ADA) activity, T and B cell percentile in total peripheral mononuclear cells, peripheral T cell subpopulation and their relationship with other inflammatory parameters in 20 patients with active pulmonary tuberculosis. Serum ADA activity showed abnormal high level in all patients in nontreated phase with significant regression after three months treatment by anti-tuberculous drugs (P less than 0.05). In addition, significant positive correlation was observed between serum ADA activity and erythrocyte sedimentation rate at 1 hour (r = 0.56). Concerning about peripheral T cell subpopulation studied by two colour flow cytometry with FITC-conjugated anti-CD4 and phycoerythrin-conjugated anti-HLA-DR antibody, there was positive correlation between CD4(-) HLA-DR(+) T cell and serum ADA activity (r = 0.59) without any abnormal frequency of each T cell subpopulation. Additionally, after the treatment of pulmonary tuberculosis, significant increase of T cell percentile in total peripheral mononuclear cells were observed (P less than 0.005). In conclusion, these results may suggest serum ADA activity could be a parameter of activity of pulmonary tuberculosis and reflect the function of activated suppressor/cytotoxic T cell.
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PMID:[Serum adenosine deaminase (ADA) activity in patients with active pulmonary tuberculosis]. 221 10

We evaluated the effects of recombinant interleukin 2 (IL-2) on the proliferative responses to mitogens of peripheral blood mononuclear cells (PBMC) from three adenosine deaminase (ADA)-deficient patients. There was significant enhancement by IL-2 of the proliferative responses to phytohemagglutinin (PHA) and pokeweed mitogen (PWM) of PBMC from all three patients. We found that normal PBMC respond with increased numbers of CD3-positive cells when exposed to PHA or PWM and that the response by normal CD8-positive cells was greater than that by CD4-positive cells. In contrast, we found that in ADA-deficient cells the response is almost entirely due to the CD3/CD4-positive population of lymphocytes. These results could not be explained by either the culture conditions or the possibility of a mixed chimeric state. When we evaluated an in vitro cell model of ADA deficiency using an ADA inhibitor, erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA), we found that the inhibitory effect of EHNA plus deoxyadenosine on mitogen-stimulated PBMC could not be prevented by IL-2. These results suggest that the immunodeficiency in ADA deficiency includes the absence or failure of a subset of T cells to make IL-2 and the failure of the CD8-positive subset to respond to IL-2. Also, the in vitro cell model of ADA deficiency using EHNA as the ADA inhibitor is limited in its use in understanding the pathogenesis of this disease.
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PMID:Interleukin 2 responsive lymphocytes in patients with adenosine deaminase deficiency. 256 54

Chronic lymphocytic leukaemia (CLL) is a disease characterised by several immune defects such as frequent autoimmune complications and functional T-cell defects, which lead to an increased risk of infections (mostly bacterial) and other tumours. Clonal chromosome abnormalities are identified in half of the patients, and trisomy 12, the most common aberration, is present in about one-third of patients with clonal changes. The commonest structural abnormalities involve chromosome 13 at band q14, the site of the retinoblastoma tumour suppressor gene. A gene located telomeric to the Rb1 gene, identified by the D13S25 probe, might be a better candidate for a pathophysiologically relevant gene in CLL, since repeated reports have identified homozygous deletions of this site. The purine analogues fludarabine and cladribine (2-chloro-2'-deoxyadenosine) and the adenosine deaminase inhibitor deoxycoformycin all have therapeutic effects in a range of lymphoproliferative disorders. Prolonged immunosuppression with low CD4 cell counts frequently occurs and, subsequently, opportunistic infections may be seen. This has to be taken into consideration when treating patients with any of these potent drugs.
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PMID:Immunological and genetic abnormalities in chronic lymphocytic leukaemia. Impact of the purine analogues. 752 86

Adenosine deaminase (ADA) expression on the surface of mitogen-stimulated lymphocytes was studied by flow cytometry. The gate for lymphocytes was located by cell size (forward scatter), cytoplasmic complexity (side scatter) and by expression of the markers CD2, CD4, CD8 and CD19. After mitogenic proliferation two populations appeared, one corresponding to non-stimulated cells, and the other consisting of larger cells which showed relatively high expression of adenosine deaminase on their surface. The increase was similar to that observed for CD71 expression, and paralleled the increase in 3H-thymidine incorporation. There was a correlation between ADA and CD71 expression (r = 0.92 for phytohaemagglutinin (PHA) and 0.97 for pokeweed mitogen (PWM)). These results suggest a role for ecto-adenosine deaminase in lymphocyte proliferation and/or triggering.
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PMID:Surface expression of adenosine deaminase in mitogen-stimulated lymphocytes. 834 57

The efficient introduction of exogenous genes into primary lymphocytes is potentially important both for somatic cell gene therapy and for studying lymphocyte biology. We describe the use of retroviral vectors to efficiently introduce exogenous genes into primary, mature murine lymph node T and B cells, and primary, immature murine CD4- CD8- double-negative (DN) thymocytes. Efficient infection of primary cells was achieved by cocultivation of target cells with lethally irradiated helper cells that produce high titers of retroviral vectors containing either the neomycin phosphotransferase II (neo) gene, or both the neo and the human adenosine deaminase (ADA) genes, in the presence of lymphokines and/or mitogens. Two days postinfection, without neomycin selection, one to five copies of the exogenous genes per cell were detected by Southern blot analysis. Expression of the exogenous human ADA protein was detected at levels comparable to the endogenous murine ADA protein in the mature T and B lymphocytes, and was somewhat lower for the immature DN thymocytes.
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PMID:Efficient gene transfer into primary murine lymphocytes obviating the need for drug selection. 839 52


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