title: Potentiation of neutrophil aggregation by human leukocyte inhibitory factor.
abstract: The current studies were designed to extend our investigations on the ability of the lymphokine leukocyte inhibitory factor (LIF) to function as a neutrophil activator. Specifically, we investigated whether LIF could modulate neutrophil (PMN) aggregation. Aggregation was measured as the increase in light transmission using a Payton aggregometer. We found that up to 16 units of LIF was not able to directly induce PMN clumping. However, when preincubated with 0.5-16 units LIF for 10 min, PMN aggregation was significantly enhanced in a dose-dependent manner after stimulation with 10(-7) M FMLP (94.5 +/- 3.1%), 20 nM leukotriene B4 (183.1 +/- 8.2%), and 100 micrograms guinea pig serum-opsonized zymosan (29.8 +/- 8.6%). While the LIF preparation used in these studies was highly purified, specificity for the LIF effect was demonstrated by the ability of several treatments to prevent augmentation of aggregation including: (1) the competitive binding of LIF to one of its substrates: benzoyl-arginine-ethyl-ester; (2) the blocking of PMN LIF receptors with N-acetyl-D-glucosamine; and (3) phenylmethylsulfonylfluoride treatment of the LIF preparation. As aggregation is thought to represent the in vitro correlate to adherence, these studies provide further evidence for a proinflammatory role for LIF in vivo.
authors.affiliation: Department of Medicine, New England Medical Center, Boston, Massachusetts 02111.
authors.forename: H
authors.initials: H
authors.lastname: Schainberg
authors.forename: L
authors.initials: L
authors.lastname: Borish
authors.forename: R E
authors.initials: RE
authors.lastname: Rocklin
mesh_terms: D002449:Cell Aggregation / Q000187:drug effects; D002478:Cells, Cultured; D006801:Humans; D007975:Leukotriene B4 / Q000494:pharmacology; D008222:Lymphokines / Q000037:antagonists & inhibitors / Q000276:immunology*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000276:immunology*; D015054:Zymosan / Q000494:pharmacology
chemical_list: D008222:Lymphokines; C010598:leukocyte inhibitory factor; D007975:Leukotriene B4; D009240:N-Formylmethionine Leucyl-Phenylalanine; D015054:Zymosan