ABSTRACT
The transcription factor Bright up-regulates Ig H chain production from select V region promoters and requires Bright dimerization, Bruton's tyrosine kinase (Btk), and the Btk substrate, TFII-I, for this activity. Defects in Btk cause X-linked immunodeficiency disease in mice and humans. Btk-deficient mice exhibit decreased serum IgM production, B cell developmental blocks, absence of peritoneal B1 cells, and subnormal immune responses against Ags, including phosphorylcholine, which confer protection against Streptococcus pneumoniae. Transgenic mice expressing dominant-negative Bright share similarities with Btk-deficient mice, including decreased serum IgM, poor anti-phosphorylcholine responses, and slightly reduced numbers of mature B cells. Although dominant-negative Bright mice developed B1 B cells, these were functionally deficient in Ig secretion. These data suggest a mechanistic explanation for the abnormal responses to phosphorylcholine observed in Btk-deficient mice, and indicate that Bright functions in a subset of Btk-dependent pathways in vivo, particularly those responses dominated by B1 B cells.
Subject(s)
B-Lymphocyte Subsets/immunology , B-Lymphocytes/immunology , Oncogenes/genetics , Trans-Activators/genetics , Trans-Activators/metabolism , Agammaglobulinaemia Tyrosine Kinase , Amino Acid Sequence , Animals , Antibodies/blood , Antigens, CD19/genetics , Blotting, Western , DNA-Binding Proteins , Enzyme-Linked Immunosorbent Assay , Female , Flow Cytometry , Humans , Immunohistochemistry , Lymphocyte Activation/immunology , Male , Mice , Mice, Transgenic , Molecular Sequence Data , Promoter Regions, Genetic , Protein-Tyrosine Kinases , Reverse Transcriptase Polymerase Chain Reaction , T-Lymphocytes/immunology , Transcription FactorsABSTRACT
Quality assurance (QA) is essential for data accuracy and proper evaluation of study objectives in clinical trials. The Tuberculosis Trials Consortium (TBTC)-a collaboration of 28 clinical sites and the Centers for Disease Control and Prevention-has developed a comprehensive QA program that provides quantitative assessments of performance based on clearly defined standards that are communicated to data collectors through a feedback process. The Implementation and Quality Committee of the TBTC developed a Site Evaluation Report (SER) that assesses performance measures (PMs) critical to the accomplishment of study objectives. PMs are defined, quantified, and evaluated, and goals and minimum acceptable scores are specified. Sites not meeting a PM minimum must provide an explanation and develop a plan to meet the goal. Site-specific and system-wide problems can be readily identified through this process. The SER is used prospectively for all TBTC treatment trials, and a Web site has been developed to maximize the availability and usefulness of performance data. The TBTC's comprehensive QA program is an example of a successful method for ensuring high quality, evaluable data.
Subject(s)
Antitubercular Agents/administration & dosage , Quality Assurance, Health Care , Randomized Controlled Trials as Topic , Tuberculosis, Pulmonary/drug therapy , Databases as Topic , Double-Blind Method , Humans , Prospective StudiesABSTRACT
Recent data indicate that certain pro-inflammatory cytokines are transcriptionally upregulated in the spinal cords of G93A-SOD1 mice, a model of amyotrophic lateral sclerosis (ALS). We previously showed that the receptor for tumor necrosis factor alpha (TNF-R1) was notably elevated at late presymptomatic as well as symptomatic phases of disease (J. Neurochem. 82 (2002) 365). We now extend these findings by showing that message for TNFalpha, as well as mRNA for interferon gamma (IFNgamma) and transforming growth factor beta1/2 (TGFbeta1, TGFbeta2), is simultaneously increased. Furthermore, TNFalpha protein is significantly increased in G93A-SOD1 mouse spinal cords, as are protein levels for interleukin-6 (IL6), IFNgamma, and the chemokines RANTES (CCL5) and KC. The interaction of TNFalpha, IL6, and IFNgamma proteins was modeled in vitro using Walker EOC-20 murine microglia with nitrite (NO(2)(-)) efflux as a quantitative index of cell response. TNFalpha alone caused robust NO(2)(-) flux, while IL6 had a lesser effect and neither IFNgamma nor IL1beta was active when applied singly. The TNFalpha stimulus was potently magnified in the presence of IL6 or IFNgamma. When applied in combination at very low concentrations, IFNgamma co-synergized with IL6 to produce a multiplicative increase in NO(2)(-) after stimulation with TNFalpha. Taken together, these data suggest that modest increases in multiple synergistic cytokines could produce a disproportionately severe activation of microglia within the degenerating spinal cord. Our data support a model wherein TNFalpha acts as a principal driver for neuroinflammation, while several co-stimulating cytokines and chemokines act to potentiate the TNFalpha effects.
