Study of interaction between the polyoxidonium immunomodulator and the human immune system cells

Abstract Polyoxidonium (PO) is a high-molecular weight physiologically active compound with pronounced immunomodulating activity, an N-oxidized polyethylene-piperazine derivative. The aim of our work was to study cellular and molecular mechanisms of the action of PO on the human peripheral blood leukocytes. By means of flow cytometry it was established that the binding of fluorescein-isothiocyanate-labeled PO (FITC-labeled PO) occurs more rapidly with monocytes and neutrophils than with lymphocytes (7-to 8-fold weaker as compared with monocytes). Using colloidal gold-labeled PO and electron microscopy it was shown with that the preparation penetrates into leukocytes by endocytosis. PO is localized in endoplasmic vesicles of cellular cytosol. Analysis of one of the crucial signal transducer, the intracellular Ca 2+ , performed with the Fluo-3 fluorescent dye, showed that PO does not induce Ca 2+ mobilization from the intracellular calcium stores and influx of extracellular Ca 2+ . The study of the intracellular hydrogen peroxide (H 2 O 2 ) production with the 2V ,7V -dichlorfluorescein indicator demonstrated that PO significantly increases the level of intracellular H 2 O 2 in monocytes and neutrophils, however, this increase is much less as compared with phorbol myristate acetate stimulation. The analysis of immunomodulating effect produced by PO proved its stimulating activity on some cytokines production in vitro, e.g. interleukin 1h (IL-1h), tumor necrosis factor (TNF)-a and IL-6. A dose-dependent increase in the intracellular killing by blood phagocytes was established under the action of PO.

Применение рибосомального препарата рибомунила для коррекции иммунной системы у больных хроническим бронхитом

.

Mucosal epithelial cells and novel approaches to immunoprophylaxy and immunotherapy of infectious diseases

Innate immune defense mechanisms activated by pathogen recognition can be roughly divided into two categories: 1) those aimed at direct killing of the pathogen (microbicidal); 2) those aimed at the development of inflammation (pro-inflammatory). The final goal of both types of mechanisms is elimination of the pathogen and restoration of homeostasis. However, inflammation is accompanied by damage of self tissues, which often has a negative impact on the outcome of infection. Therefore, there is a need in such approaches to immunoprophylaxy and immunotherapy of infections that would enhance antimicrobial defense while minimizing inflammation. A key approach is elevation of epithelial barrier resistance. The proposed concept of immunostimulation is exemplified using COVID-19 infection

MATURATION OF MACROPHAGES UNDER THE INFLUENCE OF MURAMYL PEPTIDES

Abstract. Muramyl peptides from bacterial cell wall trigger the modifications in macrophages similar to maturation observed with dendritic cells. Mature macrophages reduced their capacity for phagocytosis, comparing with control, while the bactericidal activity increased. Phenotype analysis of human macrophages exposed to muramyl peptides showed the increasing expression of costimulatory receptors and antigen presenting molecules. On the other hand, there was downregulation of receptors involved in recognition and engulfing of microorganism. In response to bacterial component macrophages secreted several cytokines: IL–12, TNFα, IL–6. (Med. Immunol., 2005, vol.7, № 1, pp. 21526

APPLICATION OF INHIBITOR ANALYSIS FOR STUDYING MECHANISMS AND ACTIONS OF POLYMURAMYL, A MURAMYL PEPTIDE-BASED IMMUNE MODULATOR

In present study, the following low-MW inhibitors were used to dissect mechanisms of action for two muramyl peptide components of Polymuramyl, an immunomodulatory drug: (1) N-acetyl-D-glucosaminyl-(β1→4)-N-acetyl-D-muramoyl-L-alanyl-D-isoglutaminyl-meso-diaminopimelic acid (GMtri); (2) a dimeric   muramyl peptide (diGMtetra), wherein two monomers [N-acetyl-D-glucosaminyl-(β1→4)-N-acetyl-D-muramoyl-L-alanyl-D-isoglutaminyl-meso-diaminopimeloyl-D-alanin] are linked via an amide bond between the carboxyl group of terminal D-alanin at one monomer and the ω-amino group of meso-diaminopimelic acid at another monomer. In vitro production of tumor necrosis factor (TNF) by human macrophages stimulated with GMtri or diGMtetra was shown to be inhibited by SB203580 (a RIP2 kinase inhibitor), genistein (a protein tyrosine kinase inhibitor) and BAY 11-7082 (an IκB-kinase inhibitor). Moreover, response to diGMtetra was inhibited by dynasore (an inhibitor of clathrin-dependent endocytosis), as well as by a broad-range protease-inhibiting cocktail. Thus, activating effects upon macrophages induced by the Polymuramyl components is provided by, at least, three biological processes: (1) clathrin-dependent endocytosis; (2) peptidase-mediated processing of diGMtetra; 3) activation of a signal chain RIP2 – IκB-kinase – NF-κB transcription factor