1,721,015 research outputs found
Determination of avidity of anti-albumin antibodies in the mouse. Influence of the number of cells transferred to the quality of the secondary adoptive response.
No full textWe observed that the volume of any anti-HSA serum needed to bind 50 per cent of the antigen is a linear function of the amount of antigen present in the reaction mixture over three log units. The slope is characteristic of each antiserum and reflects the `avidity' of the antibodies.
By using this quantitative index we found that the avidity of antibodies produced during the secondary adoptive response depends on the number of the cells transferred: few cells will produce antibodies of lower avidity than many cells. The dose of antigen given as a booster also influences the quality of the antibody produced; in the extreme case where some primed cells were rendered `tolerant' by supra-optimal doses of challenging antigen, substantial amounts of low avidity antibodies were synthesized. The results can be explained by competition for antigen among competent cells, favouring those cells which carry antibody sites with high affinity for the corresponding antigenic determinant
Antibody-mediated activation of beta-galactosidase mutants and complementing fragments
No full textThe activation by antibody of the defective Z gene product (AMEF) of a lac-negative E.coli is being investigated with the aim of deriving a general mechanism for antibody-mediated conformational changes in proteins. The present data on kinetics of activation and on the effect of substrate analogs on the mutant beta-galacotsidase show that interaction with different ligands at specific sites of the proteins can stabiliza or induce an enzymatically active conformation similar to that of the wild type enzym
Beta-Galactosidase: immune recognition of conformation and mechanism of antibody-induced catalytic activation
No full textActivation of mutant β-galactosidase by antibodies can be explained by a “selection” mechanism in which the antibody binds and stabilizes those mutants in a native-like conformation and by an “induction” mechanism where binding of the antibody itself induces a conformational change activating β-galactosidase. The “selection” hypothesis was tested by passing β-galactosidase through a column packed with monoclonal antibody-derivatized Sepharose. The antibody retains the active, in preference to the inactive, proteins. The “induction” mechanism was tested by mixing antibody–Sepharose with mutant β-galactosidase and measuring enzyme activity before mixing and that remaining in the supernatant. The activity of the antibody–Sepharose pellet exceeded the sum of the original activity plus supernatant activity. As a result of these experiments, both mechanisms are found to be operative
An enzymatically active antigen-antibody probe to measure circulating immune complexes by competition. I. Use of Escherichia coli beta-galactosidase in the probe and of bovine conglutinin as the complex-binding reagent
No full textAntibody-mediated activation of genetically defective Escherichia coli beta-galactosidases by monoclonal antibodies produced by somatic cell hybrids
No full textEffect of cyclosporine on the antigen-presenting function of human and murine accessory cells.
No full textCold-precipitable immune complexes in collagen diseases: evidence for the coexistence of multiple types of circulating complexes in the same serum
No full textIn patients with systemic lupus erythematosus, mixed cryoglobulinemia, and rheumatoid arthritis, the presence of cold-precipitable immune complexes (IC) was investigated by means of two different methods, i.e., the Clq-binding activity (ClqBA) and a competitive enzyme immunoassay, based on solid-phase bovine conglutinin (K). Cold precipitability of IC ranged between 0 and 100% with K and between 0 and 71% with ClqBA. No correlation existed either between the levels or the cold precipitability of the IC measured by the two systems in the same sera. On the whole, cold-precipitable IC were better determined by the K method than by ClqBA and in mixed cryoglobulinemia cryocrit levels correlated with IC levels determined with K, but not ClqBA. These data provide direct evidence of the coexistence of several types of circulating IC in the same serum and that the two methods recognize, at least in part, different IC in the same specimen. It might be hypothesized that different IC present in a serum may have a distinct biological significance
Monoreactive and polyreactive rheumatoid factors produced by in vitro Epstein-Barr virus-transformed peripheral blood and synovial B lymphocytes from rheumatoid arthritis patients.
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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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