Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.7 (DNA polymerase)
 17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although the identity of T cells involved in the protection against Mycobacterium tuberculosis (Mtb) in humans remain unknown, patients with pulmonary tuberculosis (TB) have reduced numbers of Mtb-reactive, V gamma 9+/V delta 2+ T cells in their blood and lungs. Here we have determined whether this gamma deltaT loss is a consequence of Mtb Ag-mediated activation-induced cell death (AICD). Using a DNA polymerase-mediated dUTP nick translation labeling assay, 5% or less of freshly isolated CD4+ alpha beta or gamma delta T cells from normal healthy individuals and TB patients were apoptotic. However, during culture Mtb Ags induced apoptosis in a large proportion of V gamma 9+V delta 2+ peripheral blood T cells from healthy subjects (30-45%) and TB patients (55-68%); this was increased further in the presence of IL-2. By contrast, anti-CD3 did not induce any significant level of apoptosis in gamma delta T cells from healthy subjects or TB patients. Mtb Ag stimulation rapidly induced Fas and Fas ligand (FasL) expression by gamma delta T cells, and in the presence of metalloproteinase-inhibitors >70% of gamma delta T cells were FasL+. Blockade of Fas-FasL interactions reduced the level of Mtb-mediated gamma delta T cell apoptosis by 75 to 80%. Collectively, these findings demonstrate that Mtb-reactive gamma delta T cells are more susceptible to AICD and that the Fas-FasL pathways of apoptosis is involved. AICD of gamma delta T cells, therefore, provides an explanation for the loss of Mtb-reactive T cells during mycobacterial infection.
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PMID:Involvement of the Fas/Fas ligand pathway in activation-induced cell death of mycobacteria-reactive human gamma delta T cells: a mechanism for the loss of gamma delta T cells in patients with pulmonary tuberculosis. 968 24

The performance of an automated DNA amplification assay (Roche Cobas Amplicor Mycobacterium Tuberculosis Test (aPCR) was compared with an in-house single tube nested polymerase chain reaction (nPCR) for the direct detection of Mycobacterium tuberculosis in respiratory specimens. Among 385 specimens, 56 were culture positive for mycobacteria (44 positive for Mycobacterium tuberculosis and 12 positive for non-tuberculosis mycobacteria). The diagnostic sensitivities of aPCR and nPCR were 86% and 91% whereas a 100% diagnostic specificity of both assays was attained. By aPCR, inhibitors were detected in 6% of the clinical samples. For nPCR, the usage of a new thermostable DNA polymerase facilitated pre-PCR decontamination using uracil-N-glycosylase and "hot start" in single step procedure. The results of the study indicated that DNA amplification assays, either manual or automated, were rapid and specific tools for diagnosing pulmonary tuberculosis.
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PMID:Direct detection of Mycobacterium tuberculosis in respiratory specimens using an automated DNA amplification assay and a single tube nested polymerase chain reaction (PCR). 980 68