1317components increase the sensitivity of platelets to ADP by actively interacting with the cell membrane. This assumption does not contradict the findings of other researchers who demonstrated a stimulatory effect of peptoglycans of nontoxigenic DCB on cultured immune cells in vitro.Thus, this study has shown that diphtheria toxin, diphtheria anatoxin, and codivac are agents that directly affect the functional activity of human platelets. In addition, it was found that diphtheria toxin and anatoxin reduce ADP-induced and total platelet aggregation, the decrease being dependent on preparation dose and incubation time. However, codivac, a glycopeptide from the cell wall of nontoxigenic DCB, stimulates platelet a~gregation in all experimental series.The cytotoxic activity of natural killer cells against 3H-uridine-labeled target cells (human erythromyeloleukosis cells K-562) and the intensity of spontaneous blast transformation are studied in vitro in the presence of human serum T-globulin. It is shown that spontaneous blast transformation is 49-51% due to the presence of aggregated ?-globulin, while the aggregate-free y-globulin fraction does not induce this reaction. The cytotoxic activity of natural killer cells in vitro declines in the presence of native ~,-globulin, which is related to the influence of aggregated y-globulin, the intensity of whose formation may increase upon a manyfold decrease in the y-globulin content of the preparation.
The cytotoxic activity of natural killer cells and the intensity of conjugate formation are studied in vitro in the natural cytotoxicity reaction against 3H-uridine-labeled human erythromyeloleukotic cells K-562 in the presence of fibronectin, T-globulin, and fibronectin/T-globulin combination. It is demonstrated that fibronectin does not change natural cytotoxicity, T-globulin increases the activity of human natural killer cells, and the fibronectin -T-globulin combination increases both the intensity of conjugate formation and the cytotoxic activity of natural killer cells. Key Words: natural killer cells; fibronectin; regulationA broad spectrum of interactions of human natural killer cells (NK) with different target cells (TC) is strongly influenced by the high degree of expression of adhesion molecules (LFA-1 and LFA-3) [12] and integrins (VLA-4 and VLA-5) [7,16] by them. Expression of these molecules on the NK surface correlates with the intensity of effector:target (E:T) conjugate formation [12]. These molecular complexes mediate not only the interaction of NK with the pericellular matrix components and other cells but also the adhesion to fibronectin (FN) [16,18] which is synthesized and expressed by NK [7,15] as a factor significant in the realization of the cytotoxic potential of the effectors of natural cytotoxicity (NCT) [15].The diversity of interactions between FN and different blood serum components implies that the Laboratory of Immunochemistry, N. F. Gamaleya Institute of Epidemiology and Microbiology, Russian Academy of Medical Sciences, Moscow effects of this protein in the organism are realized not by native but rather by modified molecules with considerably altered structural and functional characteristics due to partial catabolic cleavage involving R-proteins which exhibit affinity for FN [1], or resulting from the interaction of FN with aggregated IgG molecules which bind to both immobilized and dissolved FN [14]. Since serum IgG occur as complexes with proteins and protein components specifically bound to the C-terminal end of Fab-fragments [2], the above-mentioned interactions, including the formation of so-called natural antibodies during complexation of IgG with the products of partial catabolic cleavage of R-proteins [3], can change the delicate mechanisms of FN binding to the lymphocyte surface and the dynamics of cell-cell interactions realized via adhesion at the early stages, specifically, the reactions of antibody-dependent cellular cytotoxicity and lymphokme production [16].
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.