title: Determination of tumor necrosis factor-alpha responsiveness in piglets around weaning using an ex vivo whole blood stimulation assay.
abstract: Ex vivo whole blood stimulation with endotoxin has proved to be a useful method for quantitative evaluations of the pro-inflammatory cytokine tumor necrosis factor alpha (TNF-alpha) response ability in humans. In the present study, a dose- and time-response study was carried out in order to develop an ex vivo whole blood stimulation assay for the quantification of TNF-alpha production in pigs. The TNF-alpha response was enhanced with increasing endotoxin stimulation dose. The maximum TNF-alpha response occurred after 2-8 h of stimulation. Subsequently, the assay was used to evaluate the TNF-alpha response in pigs (n=32) in relation to weaning. The TNF-alpha response was 332 pg ml(-1) (+/-59 pg) plasma 2 days before weaning and 127 pg ml(-1) (+/-23 pg) plasma 2 days after weaning, which was a significant reduction (p<0.001). Total and differential counts of leucocytes were the same before and after weaning. Thus the lower TNF-alpha response may be due to reduced monocyte responsiveness to the endotoxin, rather than caused by a reduction in monocyte numbers. The reduced TNF-alpha response in piglets after weaning may be a factor of importance to the increased disease susceptibility seen in piglets in this period.
authors.affiliation: Danish Institute of Agricultural Sciences (DIAS), Department of Animal Health and Welfare, P.O. Box 50, DK-8830 Tjele, Denmark. lone.carstensen@agrsci.dk
authors.forename: Lone
authors.initials: L
authors.lastname: Carstensen
authors.forename: Christine Maria
authors.initials: CM
authors.lastname: Røntved
authors.forename: Jens Peter
authors.initials: JP
authors.lastname: Nielsen
mesh_terms: D000818:Animals; D000833:Animals, Suckling; D005260:Female; D007958:Leukocyte Count / Q000662:veterinary; D008070:Lipopolysaccharides / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology; D008214:Lymphocytes / Q000276:immunology; D009000:Monocytes / Q000276:immunology; D009504:Neutrophils / Q000276:immunology; D012044:Regression Analysis; D013047:Specific Pathogen-Free Organisms; D013552:Swine / Q000097:blood / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology*; D014886:Weaning
chemical_list: D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha