Effect of Pasteurella haemolytica saline capsular extract on bovine pulmonary endothelial cells.
The purpose of this in vitro study was to determine whether Pasteurella haemolytica capsular extract (CE) damages bovine pulmonary endothelial cells (EC) directly or through neutrophil-mediated mechanisms. Chromium 51-labeled EC were treated with the following variables: CE (1, 10, and 100 ng of protein/ml), CE and bovine neutrophils (10(6) cells/well), and CE and polymyxin B (500 U/ml). Although only minimal damage to EC occurred by 5 hours after treatment, by 22 hours after treatment, the 10-ng and 100-ng CE dose produced severe damage to EC, as indicated by 51Cr release, cellular detachment, and loss of monolayer confluency. The component in the CE that was toxic to the EC was lipopolysaccharide, evidenced by effective neutralization of the toxic effect with polymyxin B. Neutrophils inhibited the CE-mediated EC toxicity and were activated, as indicated by shape change and adhesion to EC monolayers. We concluded that the lipopolysaccharide component of CE causes direct damage to EC, which can be attenuated by neutrophils and polymyxin B.
Kumar
S
S
Department of Pathobiology, College of Veterinary Medicine, University of Tennessee, Knoxville 37901-1071.
Breider
M A
MA
Corstvet
R E
RE
Maddux
J L
JL
D000818:Animals; D002417:Cattle; D002448:Cell Adhesion; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects*; D008070:Lipopolysaccharides / Q000633:toxicity*; D016978:Mannheimia haemolytica / Q000737:chemistry*; D009504:Neutrophils / Q000166:cytology; D011112:Polymyxin B / Q000494:pharmacology; D011135:Polysaccharides, Bacterial / Q000633:toxicity*; D011651:Pulmonary Artery / Q000166:cytology / Q000187:drug effects*
D008070:Lipopolysaccharides; D011135:Polysaccharides, Bacterial; D011112:Polymyxin B