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)

Because others had described a lack of the enzyme adenosine deaminase as associated with severe combined immunodeficiency, we surveyed kindreds with infants affected with such an immunodeficiency. Three infants in two families with severe combined immunodeficiency were found to have no detectable erythrocyte adenosine deaminase. Eleven family members heterozygous for adenosine deaminase deficiency were encountered among the first-degree relatives; adenosine deaminase deficiency and severe combined immunodeficiency were associated and inherited as autosomal recessive traits in both kindreds. Successful bone-marrow transplantation was carried out in two of these infants. Normal immunologic function was established in both children, but the deficiency of adenosine deaminase persisted in their erythrocytes. The enzyme deficiency did not impair the successful establishment of normal humoral and cellular immunity by transplants of bone-marrow cells from siblings who were either normal or heterozygous for adenosine deaminase deficiency.
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PMID:Severe combined immunodeficiency and adenosine deaminase deficiency. 108 83

A retrospective study aiming at detection of heterozygous carriers of blood adenosine deaminase (ADA) deficiency was carried out in nine families known to us because children had died of combined immunodeficiency (SCID). The trait was found in 3 of 9 parent couples, and in 14 other relatives. In two families one homozygous patient was identified. A total of 54 family members and 60 healthy control subjects were tested. Clinically, the patients were all characterized by marked lymphopenia, nearly normal immunoglobulin levels, and inability to produce antibodies. One homozygous patient recovered after transplantation of fetal liver and thymus and is immunologically normal 1.5 years afterwards.
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PMID:Hereditary sever combined immunodeficiency and adenosine deaminase deficiency. 124 64

A lack of adenosine deaminase activity has been associated with severe combined immunodeficiency and decreased enzyme activity observed in acute lymphocytic leukemia. We have measured enzyme activity in lymphocytes, red blood cells, and plasma of patients with a variety of metastatic tumors. Patients with tumor had a significantly lower erythrocyte adenosine deaminase activity (p less than 0.025) and statistically higher enzyme activity in their lymphocytes (p less than 0.010) when compared with control plasmaphoresis donors. Interestingly, blood type A tumor patients showed a significant decrease in their erythrocyte enzyme concentration compared with blood group A controls (p less than 0.001) as well as a collective group of type B and O tumor patients (p less than 0.001). Type A patient lymphocyte adenosine deaminase activity was not increased and was not statistically different from control group A donors. Tumor patients with blood groups B and O considered collectively had a statistically significant increase in their lymphocyte enzyme concentration compared with group B and O controls (p less than 0.001).
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PMID:Adenosine deaminase levels in blood type A patients with metastatic tumor. 124 85

High concentrations of adenosine are known to be toxic to fibroblasts and lymphocytes under conditions of in vitro culture (1,2). Normally, accumulation of adenosine nucleotides in all mammalian cells is prevented by the presence of adenosine deaminase, an aminohydrolase which converts adenosine to inosine (3). A genetically determined deficiency of adenosine deaminase has been associated with the autosomal recessive form of severe combined immunodeficiency, a syndrome in which precursor lymphocytes fail to mature into T cells and B cells (4-7). Erythrocytes of affected infants convert exogenous adenosine to AMP and ATP at an abnormally increased rate as a consequence of the enzyme defect, and ATP at an abnormally increased rate as a consequence of the enzyme defect, and fail to form inosine from the exogenous adenosine (8). These metabolic disturbances can be mimicked in normal erythrocytes by coformycin (8), a potent competitive inhibitor of adenosine deaminase (9, 10). In this study, the effects of coformycin were examined on the in vitro function of normal lymphocytes.
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PMID:Inhibition of maturation of human precursor lymphocytes by coformycin, an inhibitor of the enzyme adenosine deaminase. 126 87

There are now rather straightforward methods to create transgenic animals whose genome is altered at the germline level. One method consists in the micro-injection of a gene into the pronucleus of a fertilized egg, the second one involves an homologous recombination event obtained in embryonic stem cells in culture. Only the latter method could eventually lead to an authentic gene therapy since it could actually substitute a normal gene for a mutated one instead of merely introducing a supplementary gene as done by micro-injection. Description of these techniques makes it obvious that germline therapy of human beings would not only be inacceptable on ethical grounds but would also hardly have any medical indications. Quite on the contrary, somatic gene therapy does not suffer from the same reservations and has numerous potential applications to man. As a matter of fact, several protocols have already received approval and have reached the stage of clinical trials: for example SCID (severe combined immunodeficiency due to a mutated adenosine deaminase gene), AIDS as well as some forms of malignant tumors.
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PMID:[Transgenesis and gene therapy]. 130 2

Peripheral blood lymphocytes obtained from a patient affected by adenosine deaminase (ADA) deficiency and severe combined immunodeficiency were infected with a retroviral vector containing two copies of a human ADA minigene, and injected into bg/nu/xid (BNX) immunodeficient mice. Six to 10 weeks after injection, human T cells were cloned from the spleens of recipient animals and analyzed for proliferative potential, T-cell surface markers, expression of ADA activity, integration of retroviral sequences, T-cell receptor (TCR) beta gene rearrangement, and specificity of antigen recognition. Efficient gene transfer and expression restored proliferative potential in vitro and long-term survival in vivo. All clonable human T lymphocytes obtained from the spleen of recipient animals had high levels of vector-derived ADA enzyme activity and showed predominantly the CD4+ phenotype. Retroviral integrations and TCR-beta gene rearrangements demonstrated the presence of a variety of different clones in the spleens of recipient mice. Furthermore, the combined analyses of vector integration and TCR rearrangement provided evidence that a circulating progenitor cell was transduced by the retroviral vector, giving rise to different and functional TCRs. Evaluation of antigen-specificity demonstrated both alloreactive and foreign antigen specific immune responses. These results suggest that restoration of enzyme activity in human ADA-deficient peripheral blood T cells by retroviral-mediated ADA gene transfer allows in vivo survival and reconstitution of specific immune functions. Therefore, retroviral vector-mediated gene transfer into circulating mononuclear cells could be successful not only in maintaining the metabolic homeostasis, but also for the development of a functional immune repertoire. This is a fundamental prerequisite for the usage of genetically engineered peripheral blood lymphocytes for somatic cell gene therapy of ADA deficiency.
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PMID:Transfer of the ADA gene into human ADA-deficient T lymphocytes reconstitutes specific immune functions. 132 9

Severe combined immunodeficiency (SCID) is a heterogeneous syndrome, due to X-linked and autosomal recessive defects. A significant proportion of the autosomal recessive forms of SCID are due to mutations at the adenosine deaminase (ADA) locus. Nine different mutations at the ADA locus, including 7 missense point mutations, have been reported in children with ADA-SCID. We could detect 5 of the 7 missense mutations associated with ADA-SCID by alterations in restriction fragments utilizing standard restriction digestion of genomic DNA and hybridization of radiolabelled ADA genomic probes to Southern transfers. We additionally developed more rapid nonradioactive methods employing digestion of genomic DNA amplified by PCR that also detected all 5 mutations. Using these methods, we have examined a sample of 45 ADA-SCID chromosomes and report that these 5 missense mutations account for one third of the ADA--chromosomes studied, with 2 mutations being relatively common.
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PMID:Five missense mutations at the adenosine deaminase locus (ADA) detected by altered restriction fragments and their frequency in ADA--patients with severe combined immunodeficiency (ADA-SCID). 134 49

Mutations at the adenosine deaminase (ADA) locus result in a spectrum of disorders, encompassing a fulminant neonatal onset severe combined immunodeficiency (SCID) and childhood onset immunodeficiency, as well as apparently normal immune function. The extent of accumulation of the toxic metabolite, deoxyATP, correlates directly with severity of disease. We have now determined the mutations on both alleles of a child with fulminant, neonatal onset ADA- SCID and accumulation of extremely high concentrations of deoxyATP. The genotype was consistent with the severely affected phenotype. One allele carried a large deletion that arose by non-homologous recombination and included the first five exons and promoter region. The second allele carried a missense mutation (G649A) resulting in replacement of Glu217, an amino acid involved in the catalytic site, by Lys and predicting a major alteration in charge. Expression of the mutant cDNA in Cos cells confirmed that the mutation abolished enzyme activity. We have previously reported that a missense mutation at the preceding codon is similarly associated with neonatal onset ADA- SCID and accumulation of extremely high deoxyATP. These findings suggest that genotype-phenotype correlations may be apparent for ADA- SCID, despite the role that random variation in exposure to environmental pathogens may play in the initial phenotype. Such genotype-phenotype correlations may be important to consider in evaluating results of ongoing trials of "gene" and enzyme replacement therapy.
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PMID:Novel deletion and a new missense mutation (Glu 217 Lys) at the catalytic site in two adenosine deaminase alleles of a patient with neonatal onset adenosine deaminase- severe combined immunodeficiency. 140 34

In order to obtain a better understanding of the degree of immune dysfunctions caused by the absence of adenosine deaminase, we gave a single i.p. injection of 2'-deoxycoformycin (2-dcf), a potent inhibitor of the enzyme ADA at various doses into adult Syrian hamsters. These animals were examined for their ability to mount primary in vivo antibody responses to helper T cell dependent (Th-d) and helper T cell independent (Th-ind) antigens. Hamsters treated with 0.5 mg/kg of 2-dcf mounted enhanced splenic plaque-forming cell (PFC) responses to sheep erythrocytes, a Th-d antigen, and to pneumococcal polysaccharide type III (SIII), a Th-ind antigen. Treatment of animals with 1.0 mg/kg of 2-dcf resulted in a significantly depressed (P less than 0.001) PFC response to Th-d antigen, but a further enhanced response to Th-ind antigen. One mechanism which may be responsible for such a dichotomous response to these two types of antigens was selective dysfunction of T cell subpopulations. At higher doses (1.5-4.0 mg/kg), PFC responses to both types of antigens were significantly suppressed. Immunoenhancement at low doses of 2-def was attributed to an increased susceptibility of T suppressor cells to 2-dcf. This hypothesis was confirmed by priming the 2-dcf-treated animals with low-dose Th-ind antigens. These animals failed to induce low-dose tolerance by stimulation of antigen-specific suppressor T cell subsets. At low doses, B cells and T helper cell functions were found to be intact, as further confirmed by priming the animals with the carrier keyhole limpet haemocyanin (KLH) and challenging with trinitrophenyl-KLH. This dose-dependent selective susceptibility of various T cell subpopulations and B cells may explain the heterogeneity of clinical, biochemical and immunological parameters observed in children with ADA deficiency severe combined immunodeficiency.
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PMID:Adenosine-deaminase-associated immunodeficiency. I. Differential sensitivities of lymphocyte subpopulations exposed to 2-deoxycoformycin in vivo. 153 36

Polyethylene glycol (PEG)-modified bovine adenosine deaminase (ADA) is used for replacement therapy of severe combined immunodeficiency disease due to inherited ADA deficiency. We monitored IgG anti-ADA antibody in 17 patients treated by intramuscular injections of PEG-ADA for 1 to greater than 5.5 yr. ELISA-detectable anti-ADA IgG appeared in 10 patients, usually between the third and eighth months of treatment. Anti-ADA levels did not correlate with trough plasma ADA activity, which averaged 1.8-5 times normal blood (erythrocyte) ADA activity, depending on dose (15-60 U/kg per wk). ELISA-detectable anti-ADA antibodies were directed primarily at bovine-specific peptide (rather than PEG-containing) epitopes. Enhanced enzyme clearance, mediated by antibody that directly inhibited native and PEG-modified bovine ADA, and native, but not PEG-modified human ADA, occurred in two patients. In one, tolerance was induced; in the second, twice weekly injections of PEG-ADA compensated for accelerated clearance. We speculate that inhibitory antibodies recognize conserved, relatively PEG-free epitope(s) encompassing the active site, and that in human, but not bovine, ADA a PEG-attachment site "shields" the active site from immune recognition. We conclude that PEG-modification largely prevents the development of high affinity, or high levels of clearing antibodies to bovine ADA, and that PEG-modified human ADA should be further investigated as a possible treatment for ADA deficiency.
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PMID:IgG antibody response to polyethylene glycol-modified adenosine deaminase in patients with adenosine deaminase deficiency. 156 4


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