Formyl peptide leukocyte chemoattractant uptake and release by cultured human umbilical vein endothelial cells.
AuthorsRotrosen D,Malech HL,Gallin JI
JournalJournal of immunology (Baltimore, Md. : 1950)
PubMed ID3668252
Recent observations support an active role for the vascular endothelial cell in the induction and evolution of the inflammatory response. Since prior studies suggested that cultured bovine endothelial cells express high affinity binding sites for the neutrophil chemotactic oligopeptide formyl methionyl-leucyl-phenylalanine (f-Met-Leu-Phe), we sought to further characterize the interaction between ... More
Signal transduction and cytoskeletal activation in the neutrophil.
AuthorsOmann GM, Allen RA, Bokoch GM, Painter RG, Traynor AE, Sklar LA
JournalPhysiol Rev
PubMed ID3543977
Domains of the human neutrophil N-formyl peptide receptor involved in G protein coupling. Mapping with receptor-derived peptides.
AuthorsSchreiber RE, Prossnitz ER, Ye RD, Cochrane CG, Bokoch GM
JournalJ Biol Chem
PubMed ID8276814
'Chemotactic signaling by the human neutrophil N-formyl peptide receptor requires its association with heterotrimeric G protein. Synthetic peptides and a fusion protein derived from the intracellular regions of the receptor were used to identify sites which interact with G protein. A peptide derived from the second intracellular loop (C12R), and ... More
Fluorescence analysis of the size of a binding pocket of a peptide receptor at natural abundance.
AuthorsSklar LA, Fay SP, Seligmann BE, Freer RJ, Muthukumaraswamy N, Mueller H
JournalBiochemistry
PubMed ID2105739
'We have studied the topography of interaction of a family of fluorescent formyl peptides containing four (CHO-Met-Leu-Phe-Lys-fluorescein), five (CHO-Met-Leu-Phe-Phe-Lys- fluorescein), and six (CHO-Nle-Leu-Phe-Nle-Tyr-Lys-fluorescein and CHO-Met-Leu-Phe-Phe-Phe-Lys- fluorescein) amino acids with their receptor using spectroscopic methods adapted to small sample volumes. Only the fluorescent peptides containing four and five amino acids were ... More
Arrestin binding to the G protein-coupled N-formyl peptide receptor is regulated by the conserved "DRY" sequence.
AuthorsBennett TA, Maestas DC, Prossnitz ER
JournalJ Biol Chem
PubMed ID10823817
'Following activation by ligand, the N-formyl peptide receptor (FPR) undergoes processing events initiated by phosphorylation that lead to receptor desensitization and internalization. Our previous results have shown that FPR internalization can occur in the absence of receptor desensitization, suggesting that FPR desensitization and internalization are controlled by distinct mechanisms. More ... More
The fate of the N-formyl-chemotactic peptide receptor in stimulated human granulocytes: subcellular fractionation studies.
'Experiments were performed to examine how human granulocytes, stimulated by N-formyl-chemotactic peptides, process the N-formyl peptide receptor. One percent of the surface N-formyl-chemotactic peptide receptors of purified human granulocytes were covalently, specifically, and radioactively labeled at 4 degrees C using the photochemically reactive N-formyl-chemotactic hexapeptide CHO-Nle-Leu-Phe-Nle-[125I] Tyr-N epsilon (6-(4'-azido-2'-nitrophenyl-amino)hexanoyl)-Lys. After ... More
Ligand/receptor internalization: a spectroscopic analysis and a comparison of ligand binding, cellular response, and internalization by human neutrophils.
'We have compared the kinetics of the responses of neutrophils to the kinetics of ligand-receptor interaction and internalization, using as a model ligand the fluoresceinated hexapeptide N-CHO-Nle-Leu-Phe-Nle-Tyr-Lys-Fluorescein (Nle, norleucine). Cellular responses, ie, membrane depolarization, enzyme (elastase) secretion, and superoxide anion (O-2) generation, are all initiated within 10 sec of the ... More
Internalization of the human N-formyl peptide and C5a chemoattractant receptors occurs via clathrin-independent mechanisms.
AuthorsGilbert TL, Bennett TA, Maestas DC, Cimino DF, Prossnitz ER
JournalBiochemistry
PubMed ID11297412
'After stimulation by ligand, most G protein-coupled receptors (GPCRs) undergo rapid phosphorylation, followed by desensitization and internalization. In the case of the N-formyl peptide receptor (FPR), these latter two processing steps have been shown to be entirely dependent on phosphorylation of the receptor''s carboxy terminus. We have previously demonstrated that ... More
Time dependence of transmembrane potential changes and intracellular calcium flux in stimulated human monocytes.
AuthorsBernardo J, Brink HF, Simons ER
JournalJ Cell Physiol
PubMed ID2826501
'An important characteristic of the functional differentiation of the blood monocyte is the development of its capacity to recognize and respond to stimuli. This ability is mediated to a large extent by specific receptor glycoproteins located on the cell surface. Stimulation of mononuclear phagocytes via these receptors results in a ... More
Influence of botulinum C2 toxin on F-actin and N-formyl peptide receptor dynamics in human neutrophils.
AuthorsNorgauer J, Just I, Aktories K, Sklar LA
JournalJ Cell Biol
PubMed ID2768337
'Stimulation of human neutrophils with the chemotactic N-formyl peptide causes production of oxygen radicals and conversion of monomeric actin (G-actin) to polymeric actin (F-actin). The effects of the binary botulinum C2 toxin on the amount of F-actin and on neutrophil cell responses were studied. Two different methods for analyzing the ... More
Leukocyte C5a receptor modulation during hemodialysis.
AuthorsLewis SL, Van Epps DE, Chenoweth DE
JournalKidney Int
PubMed ID2951551
'Exposure of blood to hemodialysis (HD) membranes results in the activation of the complement system. In this study, flow cytometry was used to analyze the binding of fluoresceinated chemotactic factors (C5a, f-Met-Leu-Phe-Lys [fMLPL], and casein) and aggregated IgG to PMN and monocytes isolated from normal whole blood following passage through ... More
Reduced expression of surface receptors for synthetic N-formylated chemotactic oligopeptides by stimulated peripheral blood neutrophils in psoriasis.
AuthorsGlinski W, Anhalt T, Mansbridge JN
JournalJ Invest Dermatol
PubMed ID3668297
'Receptors for synthetic N-formylated chemotactic peptides on peripheral blood neutrophils were studied by the binding of fluorescein-labeled hexapeptide (N-formyl-Nle-Leu-Phe-Nle-Tyr-Lys) to the cells in vitro at the range of concentrations 0.01-100 nM. Mean fluorescence of neutrophils was quantitated by a flow cytometry using FACS III. Comparison was made between 27 patients ... More
Desensitization of formyl peptide receptors is abolished in calcium ionophore-primed neutrophils: an association of the ligand-receptor complex to the cytoskeleton is not required for a rapid termination of the NADPH-oxidase response.
AuthorsLiu L, Harbecke O, Elwing H, Follin P, Karlsson A, Dahlgren C
JournalJ Immunol
PubMed ID9498791
'Binding of ligands to N-formyl peptide chemoattractant receptors exposed on human neutrophils generates signals in the cells that induce an activation of the superoxide anion producing NADPH-oxidase. Ligand binding is followed by a rapid association of the ligand-receptor complex with the cytoskeleton, a process leading to desensitization of the cells ... More
AuthorsKey TA, Foutz TD, Gurevich VV, Sklar LA, Prossnitz ER
JournalJ Biol Chem
PubMed ID12424254
'Arrestins regulate the signaling and endocytosis of many G protein-coupled receptors (GPCRs). It has been suggested that the functions of arrestins are dependent upon both the number and pattern of phosphorylation sites present in an activated GPCR. However, little is currently known about the relationships between the sites of receptor ... More
Independent regulation of human neutrophil chemotactic receptors after activation.
AuthorsBender JG, Van Epps DE, Chenoweth DE
JournalJ Immunol
PubMed ID2822801
'The fluoresceinated chemotactic factors, C5a, formyl-methionyl-leucyl-phenylalanyl-lysine (FMLPL), and casein were used in conjunction with flow cytometry to examine chemotactic factor receptor expression on polymorphonuclear leukocytes (PMN) activated with phorbol myristate acetate (PMA), C5a, or formyl-methionyl-leucyl-phenylalanine. Activation with PMA resulted in a dose-dependent increase in binding of fluorescein-labeled (FL)-casein and (FL-FMLPL) ... More
Antibody diffusion in human cervical mucus.
AuthorsSaltzman WM, Radomsky ML, Whaley KJ, Cone RA
JournalBiophys J
PubMed ID8161703
'The mucosal immune system actively transports large quantities of antibodies into all mucus secretions, and these secreted antibodies help prevent infectious entry of many pathogens. Mucus is generally thought to protect epithelial cells by forming a diffusional barrier through which only small molecules can pass. However, electron microscopy indicates that ... More
Cutting edge: selective usage of chemokine receptors by plasmacytoid dendritic cells.
AuthorsPenna G, Sozzani S, Adorini L
JournalJ Immunol
PubMed ID11489962
'The existence of dendritic cell (DC) subsets is firmly established, but their trafficking properties are virtually unknown. In this study, we show that myeloid (M-DCs) and plasmacytoid (P-DCs) DCs isolated from human blood differ widely in the capacity to migrate to chemotactic stimuli. The pattern of chemokine receptors expressed by ... More
C5a receptor modulation on neutrophils and monocytes from chronic hemodialysis and peritoneal dialysis patients.
AuthorsLewis SL, Van Epps DE, Chenoweth DE
JournalClin Nephrol
PubMed ID3488153
'Chronic renal failure patients have an increased risk for infection which may partially be due to altered chemotactic ability of their white blood cells. This study was designed to evaluate chemotactic factor and Fc receptor expression on neutrophils (PMN) and monocytes from chronic renal failure patients on hemodialysis (HD) or ... More
Validation of flow cytometric competitive binding protocols and characterization of fluorescently labeled ligands.
AuthorsWaller A, Pipkorn D, Sutton KL, Linderman JJ, Omann GM
JournalCytometry
PubMed ID11590622
'BACKGROUND: Fluorescently labeled ligands and flow cytometric methods allow quantification of receptor-ligand binding. Such methods require calibration of the fluorescence of bound ligands. Moreover, binding of unlabeled ligands can be calculated based on their abilities to compete with a labeled ligand. In this study, calibration parameters were determined for six ... More
Analysis of density changes and chemotactic receptors of leukocytes from chronic hemodialysis and peritoneal dialysis patients.
AuthorsLewis SL, Van Epps DE, Chenoweth DE
JournalBlood Purif
PubMed ID3040039
'Analysis of standard Ficoll-Hypaque (density = 1.077 g/ml) separation profiles of peripheral white blood cells (WBC) from patients undergoing hemodialysis (HD) demonstrated that dialysis caused a marked decrease in the density of polymorphonuclear leukocytes (PMN) resulting in about 50% of these cells separating with the mononuclear cells. In vitro exposure ... More
Receptor up-regulation, internalization, and interconverting receptor states. Critical components of a quantitative description of N-formyl peptide-receptor dynamics in the neutrophil.
AuthorsHoffman JF, Linderman JJ, Omann GM
JournalJ Biol Chem
PubMed ID8702483
'High resolution kinetic data of the binding of fluorescent peptide to the N-formyl peptide receptor of neutrophils at 37 degrees C has allowed for the development of a ligand binding model that predicts statistically larger binding rate constants than those previously reported for intact neutrophils. The new model accounts for ... More
Role of the plasma membrane in signal transduction in human polymorphonuclear leukocytes.
AuthorsDelBuono BJ, Simons ER
JournalJ Cell Physiol
PubMed ID8380422
'To more closely examine the role of the cell surface in transmembrane signal transduction in human neutrophils, sealed right-side-out membrane vesicles free of organellar membrane components were used as models of the plasma membrane. These vesicles, incubated with a fluorescent analogue of the chemotactic peptide fMLP, bound this ligand similarly ... More
Fluorescent probes for living cells.
AuthorsJohnson I
JournalHistochem J
PubMed ID10188922
'The functional characteristics of fluorescent probes used for imaging and measuring dynamic processes in living cells are reviewed. Initial consideration is given to general design requirements for delivery, targeting, detectability and fluorescence readout, and current technologies for attaining them. Discussion then proceeds to the more application-specific properties of intracellular ion ... More
Multiple activation steps of the N-formyl peptide receptor.
AuthorsProssnitz ER, Gilbert TL, Chiang S, Campbell JJ, Qin S, Newman W, Sklar LA, Ye RD
JournalBiochemistry
PubMed ID10029516
'The human N-formyl peptide receptor (FPR) is representative of a growing family of G protein-coupled receptors (GPCR) that respond to chemokines and chemoattractants. Despite the importance of this receptor class to immune function, relatively little is known about the molecular mechanisms involved in their activation. To reveal steps required for ... More
Fluorescent chemotactic peptides as tools to identify the f-Met-Leu-Phe receptor on human granulocytes.
AuthorsSchmitt M, Bültmann B
JournalBiochem Soc Trans
PubMed ID2379691
Analysis of ligand-receptor interactions with the fluorescence activated cell sorter.
AuthorsSklar LA, Finney DA
JournalCytometry
PubMed ID6293787
The binding of a fluorescent peptide to human neutrophils is analyzed with a fluorescence activated cell sorter. We examine steady-state and kinetic features of the ligand-receptor interaction (in the presence of unbound ligand) and we show tht the number of receptors may be estimated without resorting to any external references ... More
Receptor-mediated internalization of fluorescent chemotactic peptide by human neutrophils.
AuthorsNiedel JE, Kahane I, Cuatrecasas P
JournalScience
PubMed ID472759
Tetramethylrhodamine labeled N-formyl-Nle-Leu-Phe-Nle-Tyr-Lys is a potent chemoattractant for human neutrophils. Binding of this peptide to living neutrophils was observed by means of video intensification microscopy. At 37 degrees C, diffuse membrane fluorescence was seen initially, followed by rapid aggregation and internalization of the fluorescent peptide. These processes are dependent on ... More
Flow cytometry analysis of the expression of neutrophil FMLP receptors.
AuthorsAllen CA, Broom MF, Chadwick VS
JournalJ Immunol Methods
PubMed ID1593131
The number of cell surface FMLP receptors expressed by peripheral blood neutrophils taken from healthy individuals was quantitated using a direct fluorescence label analysed on the FACScan. Receptor numbers, assayed on cells from heparinised blood prepared at 4 degrees C or 37 degrees C or in the presence of LPS ... More
A homolog of formyl peptide receptor-like 1 (FPRL1) inhibitor from Staphylococcus aureus (FPRL1 inhibitory protein) that inhibits FPRL1 and FPR.
AuthorsPrat C, Haas PJ, Bestebroer J, de Haas CJ, van Strijp JA, van Kessel KP,
JournalJ Immunol
PubMed ID19846866
The members of the formyl peptide receptor (FPR) family are involved in the sensing of chemoattractant substances, including bacteria-derived N-formylated peptides and host-derived peptides and proteins. We have recently described two chemoattractant receptor inhibitors from Staphylococcus aureus. Chemotaxis inhibitory protein of S. aureus (CHIPS) blocks the formyl peptide receptor (FPR) ... More
Response of neutrophils to stimulus infusion: differential sensitivity of cytoskeletal activation and oxidant production.
AuthorsOmann GM, Sklar LA
JournalJ Cell Biol
PubMed ID2843551
The response of human neutrophils to N-formyl peptides were studied under conditions where ligand binding was controlled by infusing a cell suspension with the peptide over a time period comparable to the normal half-time for binding. Receptor occupancy was measured in real time with a fluorescently labeled peptide using flow ... More
An inositol tetrakisphosphate-containing phospholipid in activated neutrophils.
AuthorsTraynor-Kaplan AE, Harris AL, Thompson BL, Taylor P, Sklar LA
JournalNature
PubMed ID3393226
Inositol (1,4,5)triphosphate (InsP3) and tetrakisphosphate (InsP4) have been observed in a variety of cell types and have been proposed to play roles in the receptor-mediated rise in intracellular Ca2+ (refs 2, 3). Recently, they have been shown to act synergistically in the activation of a Ca2+-dependent K+ channel in lacrimal ... More
Fluoresceinated chemotactic peptide and high-affinity antifluorescein antibody as a probe of the temporal characteristics of neutrophil stimulation.
Antifluorescein antibody molecules were used to interrupt the stimulation of neutrophils by a fluoresceinated chemotactic peptide. From the results we construct a semiquantitative relationship among ligand-receptor interaction, the time course of cell triggering and response, and aspects of cellular adaptation. The interaction of the antibody with the free fluoresceinated peptide ... More
Is there a relationship between phosphatidylinositol trisphosphate and F-actin polymerization in human neutrophils?
AuthorsEberle M, Traynor-Kaplan AE, Sklar LA, Norgauer J
JournalJ Biol Chem
PubMed ID2211588
Stimulation of human neutrophils with the chemoattractant N-formyl peptide caused rapid polymerization of F-actin as detected by right angle light scatter and 7-nitrobenz-2-oxa-1,3-diazol (NBD)-phallacidin staining of F-actin. After labeling neutrophils with 32P, exposure to N-formyl peptide induced a fast decrease of phosphatidylinositol 4-bisphosphate (PIP)2, a slow increase of phosphatidic acid, ... More
Cell type- and developmental stage-specific activation of NF-kappaB by fMet-Leu-Phe in myeloid cells.
AuthorsBrowning DD, Pan ZK, Prossnitz ER, Ye RD
JournalJ Biol Chem
PubMed ID9065470
Chemoattractants induce a variety of phagocytic functions including transendothelial migration, degranulation, and the generation of superoxide anions. We report here that the prototypic chemotactic peptide fMet-Leu-Phe (fMLF) stimulates the activation of nuclear factor-kappaB (NF-kappaB), a transcription factor that is central to the regulation of proinflammatory immediate-early gene expression. In freshly ... More
Studies of chemotactic factor-induced polarity in human neutrophils. Lipid mobility, receptor distribution and the time-sequence of polarization.
AuthorsMcKay DA, Kusel JR, Wilkinson PC
JournalJ Cell Sci
PubMed ID1808201
Differences in membrane composition between the anterior and posterior poles of human blood neutrophils on exposure to chemoattractant were studied using a laser microscope, and the effects of attractant concentration and time on the ability of neutrophils to polarize were determined. The findings were as follows. (1) The fluorescein-labelled chemotactic ... More
Competitive binding kinetics in ligand-receptor-competitor systems. Rate parameters for unlabeled ligands for the formyl peptide receptor.
AuthorsSklar LA, Sayre J, McNeil VM, Finney DA
JournalMol Pharmacol
PubMed ID4058418
We describe the real-time kinetics of the competition of different ligands for the same receptor and use the computer routine SAAM to simulate this competition. Based on the simulation, we have developed two experimental approaches whereby the parameters of the interaction of nonlabeled ligands with their receptor can be detected; ... More
Ligand/receptor internalization: a kinetic, flow cytometric analysis of the internalization of N-formyl peptides by human neutrophils.
AuthorsFinney DA, Sklar LA
JournalCytometry
PubMed ID6617394
Fluorescence flow cytometry was used to measure the internalization of the fluorescent ligand N-formyl-nle-leu-phe-nle-tyr-lys-fluorescein by human neutrophils. The internalization process was monitored by the accessibility of the receptor-bound fluorescent ligand to quenching following a change in the pH of the extracellular medium from 7.4 to 3.0. In such a pH ... More
The potency and kinetics of the beta-adrenergic receptors on human neutrophils.
AuthorsMueller H, Motulsky HJ, Sklar LA
JournalMol Pharmacol
PubMed ID2901665
The binding to catecholamines to the beta-adrenergic receptors on human polymorphonuclear leukocytes rapidly inhibits cell responses stimulated by chemoattractant ligands. As a first step in understanding the mechanism of the inhibition, we investigated the number of beta-receptors required to optimally block superoxide anion production, a response that is measured kinetically ... More
Binding of low affinity N-formyl peptide receptors to G protein. Characterization of a novel inactive receptor intermediate.
Authors Prossnitz E R; Schreiber R E; Bokoch G M; Ye R D;
JournalJ Biol Chem
PubMed ID7738006
G protein-coupled seven-transmembrane-containing receptors, such as the N-formyl peptide receptor (FPR) of neutrophils, likely undergo a conformational change upon binding of ligand, which enables the receptor to transmit a signal to G proteins. We have examined the functional significance of numerous conserved charged amino acid residues proposed to be located ... More
Signal transduction and ligand-receptor dynamics in the neutrophil. Ca2+ modulation and restoration.
AuthorsSklar LA, Oades ZG
JournalJ Biol Chem
PubMed ID4044564
Intracellular Ca2+ rises when neutrophils are stimulated with formyl peptide ligands. There is enough Ca2+ released to complex approximately 200 microM Quin 2, (220 +/- 90 microM, 7 donors). This result is interpreted in terms of a fixed storage pool of Ca2+ of 44 pmol/10(6) cells. When extracellular Ca2+ is ... More
The ligand binding site of the formyl peptide receptor maps in the transmembrane region.
We propose that the N-formyl-Met-Leu-Phe binding site in the human neutrophil formyl peptide receptor (FPR) lies in the predicted transmembrane region. We examined the expression, binding, and G protein coupling of 28 mutated forms of FPR in stably transfected Chinese hamster ovary cells. The amino acids we mutated are: 1) ... More
The dynamics of ligand-receptor interactions. Real-time analyses of association, dissociation, and internalization of an N-formyl peptide and its receptors on the human neutrophil.
Parallel cytometric and fluorimetric analyses of the interaction of a fluoresceinated N-formyl hexapeptide (N-formyl-Nle-Leu-Phe-Nle-Tyr-Lys-fluorescein, Nle = norleucine) with its receptors on human neutrophils are presented. The cytometric analyses take advantage of the ability of the fluorescence flow cytometer to discriminate free and receptor-bound ligand in a homogeneous real-time assay. The ... More
Differential phosphorylation paradigms dictate desensitization and internalization of the N-formyl peptide receptor.
AuthorsMaestes DC, Potter RM, Prossnitz ER
JournalJ Biol Chem
PubMed ID10514456
Following activation by ligand, most G protein-coupled receptors undergo rapid phosphorylation. This is accompanied by a drastic decrease in the efficacy of continued or repeated stimulation, due to receptor uncoupling from G protein and receptor internalization. Such processing steps have been shown to be absolutely dependent on receptor phosphorylation in ... More
Desensitization of N-formylpeptide receptor-mediated activation is dependent upon receptor phosphorylation.
AuthorsProssnitz ER
JournalJ Biol Chem
PubMed ID9182544
The human N-formylpeptide receptor (FPR) represents one of the most thoroughly studied leukocyte chemoattractant receptors. Despite this, little is known about the molecular mechanisms involved in the activation and desensitization of this receptor. To assess the role of phosphorylation in receptor function, U937 promonocytic cells were stably transfected to express ... More
N-formyl peptide receptors in human neutrophils display distinct membrane distribution and lateral mobility when labeled with agonist and antagonist.
AuthorsJohansson B, Wymann MP, Holmgren-Peterson K, Magnusson KE
JournalJ Cell Biol
PubMed ID8509449
Receptors for bacterial N-formyl peptides are instrumental for neutrophil chemotactic locomotion and activation at sites of infection. As regulatory mechanisms for signal transduction, both rapid coupling of the occupied receptor to cytoskeletal components, and receptor lateral redistribution, have been suggested (Jesaitis et al., 1986, 1989). To compare the distribution and ... More
Regulation of the affinity state of the N-formylated peptide receptor of neutrophils: role of guanine nucleotide-binding proteins and the cytoskeleton.
AuthorsPainter RG, Zahler-Bentz K, Dukes RE
JournalJ Cell Biol
PubMed ID3121639
Previous studies have indicated that the receptor for N-formylated peptides present on human neutrophils can exist in several ligand-dissociation states at least one of which is sensitive to guanine nucleotides. Human neutrophil membranes rich in cell surface enzyme markers have been isolated from cells pretreated at 37 degrees C with ... More
Urokinase-type plasminogen activator receptor reversibly dissociates from complement receptor type 3 (alpha M beta 2' CD11b/CD18) during neutrophil polarization.
Previous studies have shown that the leukocyte integrin CR3 (CD11b/CD18) is physically associated with the urokinase-type plasminogen activator receptor (uPAR;CD87), a glycosyl-phosphatidylinositol (GPI)-linked protein, in resting neutrophil membranes. We now show that uPAR-to-CR3 interactions are reversible, correlating with cell shape. Neutrophils were first labeled with fluorescein conjugates of anti-CR3 F(ab')2 ... More
Relationship of actin polymerization and depolymerization to light scattering in human neutrophils: dependence on receptor occupancy and intracellular Ca++.
AuthorsSklar LA, Omann GM, Painter RG
JournalJ Cell Biol
PubMed ID4040917
When exposed to the N-formylated chemoattractant peptides, neutrophils undergo a transient ruffling followed by a polarization that involves a redistribution of F-actin (Fechheimer, M., and S. H. Zigmond, 1983, Cell Motil., 3:349-361). The cells also undergo a biphasic right angle light scatter response whose first phase is maximal 10-15 s ... More