1,721,038 research outputs found
Dictionary of Immunology
No full textImmunological vocabulary in current usage. Intended for biologists, clinicians, and biochemists of all educational levels. Particularly contains many terms in cellular immunology and immunogenetics. Entry gives term and explanatory definition
Non-histone chromatin proteins of B lymphocytes stimulated by lipopolysaccharide, III. De novo synthesis
No full textNuclear and cytoplasmic proteins synthesised by mouse lymphocytes stimulated in vitro by the B lymphocyte mitogen, lipopolysaccharide, have been analysed by one- and two-dimensional polyacrylamide gel electrophoresis at early and later times after the onset of stimulation. During the first 4 h no change was observed in the electrophoretic profiles but differences in turnover of various nuclear proteins within the same sample were noted. This is contrasted with the previous observations that phosphorylation of nuclear proteins is stimulated within 2 h. (Stott, D.I. and Williamson, A.R. (1978) Biochim. Biophys. Acta 521, 739-752). During prolonged culture, synthesis of nucleoplasmic proteins declined between day 2 and day 3, being reduced to undetectable levels at the end of the 3-day culture period. In contrast, synthesis of many non-histone chromatin proteins was stimulated between 24 and 48 h, the time course and degree of stimulation varying between different proteins. Certain proteins appeared to be synthesized de novo. These events occur at a time of rapidly increasing IgM synthesis and cell differentiation. It is suggested that an initial step in B lymphocyte triggering may involve phosphorylation of preexisting nuclear proteins leading to gene activation followed by synthesis and phosphorylation of new gene regulatory molecules
An antigen-driven B-cell response within the salivary glands of patients with Sjögren’s syndrome
Get PDFInfection with a bacterium or virus induces the production of antibodies, specialised protein molecules that bind to and eliminate the microorganism. These antibodies are produced by B-cells that are stimulated by antigen (any foreign protein or carbohydrate) in the lymph nodes and spleen. During this process, they diversify their variable region genes (V-genes), encoding the antigen-binding region of the antibody, by switching on machinery that mutates the V-genes at a very high rate (somatic hypermutation). In autoimmune diseases, B-cells produce autoantibodies against self-antigens present on the patient's own tissues. Clusters of B- and T-cells are frequently found in the target organs of autoimmune disease. The aim of the work described here was to determine whether these clusters of cells are responding to stimulation by antigen. For this purpose we investigated the B-cell response in patients with an autoimmune disease affecting the salivary and lachrymal glands. By cloning and sequencing the expressed V-genes from indvidual clusters of cells in the salivary glands, we were able to show that the B-cells in these clusters are undergoing clonal proliferation, somatic hypermutation and antigen selection. The presence of similar structures in the target tissues of other autoimmune diseases suggests that this is a widespread phenomenon
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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