title: Lipopolysaccharide and lipoteichoic acid induce different innate immune responses in bovine mammary epithelial cells.
abstract: The objective of the present study was to characterize the innate immune responses induced by in vitro stimulation of bovine primary mammary epithelial cells (bMEC) using gram-negative lipopolysaccharide (LPS) and gram-positive lipoteichoic acid (LTA) bacterial cell wall components. Quantitative real-time PCR (qRT-PCR) was employed to examine the mRNA expression of a panel of 22 cytokines, chemokines, beta-defensins and components of the Toll-Like Receptor signaling pathway. Stimulation of bMEC with LPS for 24h elicited a marked increase in mRNA expression for IL-1beta, IL-8, TNFalpha, CXCL6 and beta-defensin while members of the Toll-Like Receptor pathway, although present, were largely unaffected. Surprisingly, stimulation of these cells with LTA for 24 h did not significantly alter the expression of these genes. A time course of the expression of IL-1beta, IL-8, TNFalpha, CXCL6 and beta-defensin was subsequently performed. The mRNA levels of all genes increased rapidly after stimulation for 2-4 h with both LPS and LTA but only the former treatment resulted in sustained responses. In contrast, the increased gene expression for LTA stimulated cells returned to resting levels after 8-16 h with the exception of beta-defensin, which remained up-regulated. The limited and unsustained cytokine response to LTA may explain why mastitis caused by gram-positive bacteria has greater potential for chronic intra-mammary infection than gram-negative infection. It was concluded that bovine mammary epithelial cells have a strong but differential capacity to mount innate immune responses to bacterial cell wall components.
authors.affiliation: CSIRO Livestock Industries, Queensland Bioscience Precinct, 306 Carmody Road, St Lucia 4067, QLD, Australia.
authors.forename: Ylva
authors.initials: Y
authors.lastname: Strandberg
authors.forename: Christian
authors.initials: C
authors.lastname: Gray
authors.forename: Tony
authors.initials: T
authors.lastname: Vuocolo
authors.forename: Laurelea
authors.initials: L
authors.lastname: Donaldson
authors.forename: Mary
authors.initials: M
authors.lastname: Broadway
authors.forename: Ross
authors.initials: R
authors.lastname: Tellam
mesh_terms: D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects* / Q000276:immunology*; D007113:Immunity, Innate / Q000187:drug effects*; D007633:Keratins / Q000378:metabolism; D007700:Kinetics; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008321:Mammary Glands, Animal / Q000166:cytology / Q000187:drug effects* / Q000276:immunology*; D016328:NF-kappa B / Q000378:metabolism; D019887:Peanut Agglutinin / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics; D013682:Teichoic Acids / Q000494:pharmacology*; D023083:beta-Defensins / Q000378:metabolism
chemical_list: D016207:Cytokines; D008070:Lipopolysaccharides; D016328:NF-kappa B; D019887:Peanut Agglutinin; D012333:RNA, Messenger; D013682:Teichoic Acids; D023083:beta-Defensins; C009900:lipoteichoic acid; D007633:Keratins