Polarization of polymorphonuclear neutrophils (PMNs) can be elicited by the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (fMLP) and the microtubule-disrupting compound colchicine. Here we report on whether natural and synthetic proteinase inhibitors alter the polarizing response to these two agents. The alpha 1-proteinase inhibitor, N-tosyl-L-phenylalanine chloromethyl ketone, an...

The effects of hexachlorobiphenyls (HCBs) on superoxide (O2-) generation by guinea pig polymorphonuclear leucocytes were examined. 2,3,6,2',3',6'-HCB by itself had only a weak inductive effect on O2- generation. This compound, however, enhanced O2- generation stimulated by N-formyl-methionyl-leucyl-phenylalanine (FMLP) about twofold, but not the generation induced by phorbol myristate acetate (...

The intracellularly trapped fluorescent calcium indicator, quin 2, was used not only to monitor changes in cytosolic-free calcium, [Ca2+]i, but also to assess the role of [Ca2+]i in neutrophil function. To increase cytosolic calcium buffering, human neutrophils were loaded with various quin 2 concentrations, and [Ca2+]i transients, granule content release as well as superoxide [O2-] production ...

Influenza A virus (IAV) has previously been shown to alter chemotactic, oxidative, and secretory functions of polymorphonuclear leukocytes (PMNL). Because of the role of cytoskeletal proteins in these processes, studies were carried out to determine if IAV altered the PMNL cytoskeleton. PMNL were incubated with buffer of IAV, stimulated with f-met-leu-phe (FMLP), fixed and stained with NBD-phal...

Human exudative neutrophils have greatly increased stores of the neutrophil chemoattractant IL-8 compared with peripheral blood cells, but the mechanism for the increase is not defined. In this report, we show that treatment of peripheral blood neutrophils with the chemotactic peptide fMLP or with leukotriene B(4) or fibrinogen results in little increase in the production of IL-8 by peripheral ...

The effect of the chemotatic peptide, N-formylmethionylleucylphenylalanine (FMLP), on actin conformation in human neutrophils (PMN) was studied by flow cytometry using fluorescent 7-nitrobenz-2-oxa-l,3-diazole (NBD)-phallacidin to quantitate cellular Factin content. Uptake of NBD-phallacidin by fixed PMN was saturable and inhibited by fluid phase F-actin but not G-actin. Stimulation of PMN by >...

The deformations of neutrophils as they pass through the pulmonary microcirculation affect their transit time, their tendency to contact and interact with the endothelial surface, and potentially their degree of activation. Here we model the cell as a viscoelastic Maxwell material bounded by constant surface tension and simulate indentation experiments to quantify the effects of (N-formyl-L-met...

The relationship of N-formyl-methionyl-leucyl-phenylalanine-stimulated Na+/H+ exchange to the chemotactic responsiveness of human neutrophils was investigated. The pHi changes, measured from the equilibrium distribution of 5,5-dimethyloxazolidine-2,4-dione, were correlated with the migratory behavior of the cells as assessed by the leading front method. Exposure of cells to 10 nM FMLP caused ac...

To study the role of L-selectin in neutrophil (PMN) margination and sequestration in the pulmonary microcirculation, maximally active concentrations of C5a (900 pmol/g) and N-formylmethionyl-leucyl-phenylalanine (fMLP; 0.34 pmol/g) were injected into the jugular vein of wild-type or L-selectin-deficient C57BL/6 mice. In wild-type mice administered C5a or fMLP, 92 +/- 1% and 34 +/- 9%, respectiv...