S. aureus and E. coli change the force and work of adhesion between P- and E-selectins of endothelial cells and ligands of neutrophil granulocytes.

Thanks to the modification of the force spectroscopy method, when a neutrophil is fixed on the tip, and an endotheliocyte culture is grown on the substrate, the exact indicators of the adhesion force and adhesion work between cells have been investigated. The high variability of adhesion contacts in different donors associated with different expression profiles of neutrophils. It was found by flow cytometry that the EA.hy926 cell line actively expresses VCAM-1, as well as P- and E-selectin under the Staphylococcus aureus influence after 60 min of co-incubation. At the same time, the integral indicators of the adhesion force and adhesion work in the "neutrophil - endothelial cell" interaction were significantly inhibited by S. aureus in all studied donors. Since the VCAM-1 receptor is not involved in the adhesion bonds between neutrophils and endothelial cells, the suppression of the interaction is associated with the inhibition of P- and E-selectins, but direct receptors removal from the endothelial cells surface of the EA.hy926 cell line does not occur. Escherichia coli causes multidirectional effects in the system of interaction "neutrophil - endothelial cell", depending on the expression profile of the donor's neutrophils. However, the cumulative effect of interaction from all donors shows that in general, under the influence of E. coli, there is an increase in adhesion force and a suppression of adhesion work.

Characteristics of quantum dots phagocytosis by neutrophil granulocytes.

This article describes the main morphological and biochemical features of neutrophil granulocytes in the process of phagocytosis of two types of quantum dots (CdSe/ZnS-MPA and CdSe/CdSeZnS/ZnS-PTVP). This study is the first to observe the transfer of large aggregates of quantum dots through neutrophils. During this process the cells demonstrate high chemotactic activity. Furthermore, neutrophil pseudopodia underwent alterations during the early stages of phagocytosis. The findings demonstrated that the biochemical profile of neutrophils is practically identical after phagocytosis of both types of quantum dots, but differs significantly from neutrophil metabolism after bacterial phagocytosis.