Role of inflammatory mediators in priming, activation, and deformability of bovine neutrophils.
OBJECTIVE
To determine the capacity of inflammatory mediators tumor necrosis factor-alpha (TNF-alpha), interleukin-8 (IL-8), platelet-activating factor (PAF), lipopolysaccharide (LPS), and leukotoxin to prime, activate, or alter deformability of adult bovine neutrophils.


METHODS
Blood collected from 5 healthy adult Holstein cows.


METHODS
Isolated neutrophils or whole blood was incubated with TNF-alpha, IL-8, PAF, LPS, or leukotoxin, and neutrophil chemiluminescence, degranulation, deformability, shape change, CD11b expression, and size distribution was measured.


RESULTS
Incubation with TNF-alpha, IL-8, PAF, and LPS primed neutrophils for oxygen radical release but caused minimal oxygen radical release by themselves. None of the inflammatory mediators induced degranulation. Incubation with TNF-alpha and PAF resulted in a decrease in neutrophil deformability and induced shape change in neutrophils. Incubation with PAF consistently resulted in an increase in neutrophil size as measured by use of flow cytometry. Only IL-8 caused an increase in expression of CD11b by neutrophils.


CONCLUSIONS
Inflammatory mediators tested had minimal effects on neutrophil oxygen radical production or degranulation but did prime neutrophils for oxygen radical production. Incubation with PAF and TNF-alpha caused a decrease in neutrophil deformability and altered neutrophil shape and size. Results of our study indicate that PAF- and TNF-alpha-induced changes in neutrophil deformability and size may cause integrin- and selectin-independent trapping of neutrophils in the lungs of cattle with pneumonic pasteurellosis.
McClenahan
D
D
Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Minnesota, St Paul 55180, USA.
Fagliari
J
J
Evanson
O
O
Weiss
D
D
D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D002417:Cattle / Q000097:blood / Q000276:immunology / Q000502:physiology*; D005098:Exotoxins / Q000502:physiology; D005260:Female; D005434:Flow Cytometry / Q000662:veterinary; D018836:Inflammation Mediators / Q000502:physiology*; D016209:Interleukin-8 / Q000502:physiology; D007781:Lactoferrin / Q000097:blood; D008070:Lipopolysaccharides / Q000494:pharmacology; D008163:Luminescent Measurements; D016177:Macrophage-1 Antigen / Q000097:blood; D009504:Neutrophils / Q000201:enzymology / Q000276:immunology / Q000502:physiology*; D009195:Peroxidase / Q000097:blood; D010972:Platelet Activating Factor / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology
D005098:Exotoxins; D018836:Inflammation Mediators; D016209:Interleukin-8; D008070:Lipopolysaccharides; D016177:Macrophage-1 Antigen; D010972:Platelet Activating Factor; D014409:Tumor Necrosis Factor-alpha; C018579:leukotoxin; D009195:Peroxidase; D000469:Alkaline Phosphatase; D007781:Lactoferrin