Biomedical subjects
Publications and source records attributed to D Prikrylová.
A mathematical model of the cell cycle regulation in S. cerevisiae is proposed. The model is based on the assumption of the G1----S phase transition control mediated by two signals. One of them is correlated with the cellular energy level--its messenger could be cAMP; the second one depends on the change of the cellular growth rate (reaching the critical size) and remains hypothetical.
A mathematical model of T-B cell cooperation is adopted to describe autotolerance and autoimmunity. The model describes the development of plasma cells and T-helper cells from their precursors through activated and proliferating cells. A state of autotolerance is simulated by reducing the rate of T precursors supply (partial clonal deletion theory), while the normal rate yields a stable state of autoimmunity. During the state of autoimmunity extra-corporeal removal of autoantibody and immunosuppression are simulated. Removal of auto-antibody alone results in stimulation of the immune system and quick return to the previous state, mainly on account of activation of memory cells. Antibody overshooting is negligible. Immunosuppression leads to a slow decline in the antibody level. Synergy is clearly demonstrated between both therapies.
A mathematical description of autotolerance and autoimmunity based on the previous model of immune response for normal antigen stimulation is given. In particular, the clonal deletion theory and non-specific stimulation of T-helper cells are included. Thus, an idea about the origin of autoimmune disease and the qualitative description of its course is presented. Possible therapies, such as immunosuppression and extracorporeal removal of autoantibodies, are also discussed.
A considerable proliferation of participating cells is a characteristic feature of the immune response. This proliferation may be controlled by Interleukin 2. Assumptions on the course of the immune response under such a control are formulated, and a new mathematical model of the immune response involving regulation of the proliferation of appropriate cells is constructed.
Mathematical modelling of the course of the immune response is undoubtedly one of the most progressive and most promising areas of modern immunology. Mathematical models (along with computer programs) can be taken as "the only means of thoroughly testing and examining a large and intricate theory" (Partridge et al. 1984). The first phase of construction of mathematical models is the formulation of assumptions based on the knowledge of the facts to be modelled (manifested usually in a scheme of the presumed course of the modelled process). The first mathematical models of immune response were based on the hypothesis of a two-stage differentiation of cells participating in the humoral response, published in Prague 23 years ago (Sercarz and Coons 1962; Sterzl 1962) and illustrated by the X----Y----Z scheme. Many contemporary mathematical models still stem from this scheme which undoubtedly fits the fundamental data concerning the immune system.
A continuous macrophage hybrid population, designated MBW-1, was produced by the fusion of peritoneal macrophages from a normal AKR mouse with thymoma cells BW5147. The hybrid cells are resistant to HA selection medium. In their nearly triploid chromosome complement they carry metacentric chromosomes typical of BW5147 cells and express the typical macrophage-like characteristics (morphology of macrophages, adherence properties, phagocytosis, expression of macrophage-specific antigen and receptor for the C3b component of complement). However, they do not express Fc receptors and the receptor for SBA lectin. An interesting property is the high resistance to the toxic action of silica particles. Thanks to the unique properties, which were not observed in other, hitherto described macrophage-like cell lines, the MBW-1 cell population provides a useful material for study of macrophage functions.
Phagocytic activity (for 2-hydroxyethylmethacrylate particles) in normal and thioglycollate- or proteose peptone-stimulated peritoneal macrophages, Peyer's patches macrophages, bone marrow macrophages and macrophage-like cell lines BWM, DCH 5, PU-5-lR and RAW 264.7, in suspension and after adherence to a substrate, was tested. Results of testing showed that 2-hydroxyethylmethacrylate particles are advantageous for following the phagocytic activity of the above cell types.