Purification and characterization of a phagocytosis-stimulating factor from phagocytosing polymorphonuclear neutrophils: comparison with granule basic proteins

Purification, primary structure, and biological activity of guinea pig neutrophil cationic peptides

The guinea pig neutrophil cationic peptides GNCP-1 and GNCP-2 were purified from a granule-rich subcellular fraction of peritoneal exudate neutrophils by acid-gel electrophoresis and reversed-phase high-performance liquid chromatography. Both peptides not only released histamine from rat mast cells to the same extent but also were equally active against Staphylococcus aureus and Escherichia coli. The peptides were rich in arginine and cystine and lacked free sulfhydryl groups. Composition and sequence determinations revealed that GNCP-1 and GNCP-2 are each single polypeptides containing 31 amino acid residues and three intramolecular disulfide bonds. The complete amino acid sequence of GNCP-1 is Arg-Arg-Cys-Ile-Cys-Thr-Thr-Arg-Thr-Cys-Arg-Phe-Pro-Tyr-Arg-Arg-Leu-Gly- Thr-Cys - Ile-Phe-Gln-Asn-Arg-Val-Tyr-Thr-Phe-Cys-Cys. The sequence of GNCP-2 is identical except for the substitution of isoleucine for leucine at residue 21.

Subpopulation of alveolar macrophages inhibits superoxide anion production by macrophages

Pig alveolar macrophages are a heterogeneous population of cells. Three subpopulations or bands exist when the whole population is separated according to density. Band 1 cells are the least dense cells and constitute 9% of the total population. Bands 2 and 3 represent 44 and 47% of the total population. The three subpopulations generate superoxide anions, although to varying degrees. Band 3 cells are the most active, while band 1 cells are the least active. The amount of superoxide anions released in a mixed population of bands 1, 2, and 3 cells was less than the sum of that produced from each band assayed separately. Band 1 cells were found to inhibit by 47% the production of superoxide anions by band 3 cells. Conditioned medium from band 1 cells contains a heat-sensitive, nondialyzable, soluble factor responsible for this inhibition.

Effects of a phagocytosis-stimulating factor derived from polymorphonuclear neutrophils on the functions of macrophages

The effects of phagocytosis-stimulating factor (PSF) derived from polymorphonuclear neutrophils on macrophage functions were studied. PSF enhanced the initial rate of phagocytosis of serum-opsonized zymosan particles by macrophages, whereas it did not affect the phagocytosis of immunoglobulin G-sensitized and inert zymosan particles. Kinetic studies showed that PSF accelerated the ingestion step, but not the attachment step, of phagocytosis by macrophages. On the other hand, PSF did not affect the other macrophage functions such as O2- generation, chemotaxis, adherence, and enzyme release. These results suggest that PSF may specifically modulate the complement receptor function of macrophages. Immunoblot assay showed the absence of components in macrophage which reacted with purified antibodies against polymorphonuclear neutrophil-derived PSF, and an extract from phagocytosing macrophages had no phagocytosis-stimulating activity, indicating that the macrophages did not produce PSF-like substances.

Inhibition by suramin of the NADPH oxidase from horse polymorphonuclear leukocytes

Suramin strongly inhibits the NADPH dependent oxidative activity of the plasma membrane fraction from activated horse polymorphonuclear leukocytes. The kinetics of inhibition reveals the existence of one effective binding site located on the inner surface of the plasma membrane with an apparent Ki value for suramin of about 1 mM. Although administration of suramin to intact cells does not affect the immediate respiratory burst, prolonged preincubation in vitro with the drug results in a decrease of H2O2 production without lowering the phagocytic activity of the leukocytes. Possible implications in vivo are briefly discussed.

Migration of fish leucocytes in vitro: the effect of factors which may be involved in mediating inflammation

Plaice (Pleuronectes platessa L.) neutrophils were isolated from the kidney on a discontinuous Percoll gradient and from the peritoneal cavity at the peak of a glycogen-elicited inflammatory response. The migratory ability of neutrophils was assessed using a 48-well microchemotaxis chamber, with an incubation of 1.5 h at 12 degrees C. The two neutrophil populations showed different responses to N-formylmethionyl-leucyl-phenylalanine (FMLP). Whereas kidney neutrophils only showed a significant enhancement of migration at 10(-7) M, inflammatory neutrophils exhibited a bimodal response, with one peak of migratory activity at 10(-9) M and a second at greater than 10(-6) M. Kidney neutrophils showed a consistent response with various concentrations of a 24 h culture supernatant of Vibrio alginolyticus. In every case increased migration was observed with 5-, 10- and 100-fold dilutions, with the latter two conditions producing a significant enhancement (p less than 0.01 and p less than 0.05 respectively). The undiluted and 2-fold diluted supernatant caused a decreased cell migration compared with control values. The supernatant from kidney neutrophils cultured with serum-opsonized, heat-killed V. alginolyticus produced greater migratory activity than neutrophils or the treated bacteria incubated alone (the controls). In each case, the enhanced activity of the supernatant was detectable by 1 h of incubation. By 4 h, the activity of the neutrophil/bacteria supernatant was significantly higher than that of the controls (p less than 0.01), but by 24 h had fallen to control levels. There was no evidence for a chemotactic response with FMLP, the bacterial supernatant or the neutrophil-derived factor and the responses were therefore assumed to be chemokinetic.

Identification of precursor of phagocytosis-stimulating factor in guinea pig polymorphonuclear neutrophils

A precursor of phagocytosis-stimulating factor (PSF) was identified by immunoblot assay with purified anti-PSF antibodies. The purified anti-PSF antibodies recognized not only the PSF with a molecular weight of 16,000 (16K) but also the 36K protein with a pI of 6.5 in the granule fraction of polymorphonuclear neutrophils, indicating that this 36K protein has an antigenic determinant common to PSF. In addition, the appearance of the PSF during phagocytosis by polymorphonuclear neutrophils was closely correlated to the decrease of the 36K protein. These results suggest that the 36K protein is the precursor of PSF which is converted to biologically active PSF in the granules during phagocytosis.