The inflammatory response of primary bovine mammary epithelial cells to Staphylococcus aureus strains is linked to the bacterial phenotype

• Published in: PloS one 2014-01, Vol.9 (1), p.e87374-e87374
• Main Authors: Zbinden, Christina, Stephan, Roger, Johler, Sophia, Borel, Nicole, Bünter, Julia, Bruckmaier, Rupert M, Wellnitz, Olga
• Format: Article
• Language: English
• Subjects: Adhesion; Agglutination; Animals; Bacteria; Biology; Cattle; Cell adhesion; Cyclooxygenase-2; Cytokines; Dairy cattle; Enzymes; Epithelial cells; Epithelial Cells - immunology; Epithelial Cells - microbiology; Female; Food safety; Gene expression; Genetic aspects; Granulocyte-macrophage colony-stimulating factor; Immune response; Immune system; Inflammation; Inflammation - immunology; Inflammation - microbiology; Inflammatory response; Interleukin 8; Lactoferrin; Latex; Latex agglutination; Mammary gland; Mammary Glands, Animal - immunology; Mammary Glands, Animal - microbiology; Mastitis; Mastitis, Bovine - immunology; Mastitis, Bovine - microbiology; Medicine; Milk; Pathogens; Phenotype; Physiology; Proteins; RANTES; Reverse transcription; RNA; RNA, Messenger - genetics; RNA, Messenger - immunology; Rodents; Staphylococcal Infections - immunology; Staphylococcal Infections - microbiology; Staphylococcus aureus; Staphylococcus aureus - genetics; Staphylococcus aureus - immunology; Strains (organisms); TLR2 protein; Toll-like receptors; Tumor necrosis factor-TNF; Tumor necrosis factor-α; Veterinary Science; Virulence; Virulence (Microbiology); Virulence factors; Virulence Factors - genetics; Virulence Factors - immunology
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0087374

Staphylococcus aureus is a major mastitis-causing pathogen in dairy cows. The latex agglutination-based Staphaurex test allows bovine S. aureus strains to be grouped into Staphaurex latex agglutination test (SLAT)-negative [SLAT(-)] and SLAT-positive [SLAT(+)] isolates. Virulence and resistance gene profiles within SLAT(-) isolates are highly similar, but differ largely from those of SLAT(+) isolates. Notably, specific genetic changes in important virulence factors were detected in SLAT(-) isolates. Based on the molecular data, it is assumed that SLAT(+) strains are more virulent than SLAT(-) strains. The objective of this study was to investigate if SLAT(-) and SLAT(+) strains can differentially induce an immune response with regard to their adhesive capacity to epithelial cells in the mammary gland and in turn, could play a role in the course of mastitis. Primary bovine mammary epithelial cells (bMEC) were challenged with suspensions of heat inactivated SLAT(+) (n = 3) and SLAT(-) (n = 3) strains isolated from clinical bovine mastitis cases. After 1, 6, and 24 h, cells were harvested and mRNA expression of inflammatory mediators (TNF-α, IL-1β, IL-8, RANTES, SAA, lactoferrin, GM-CSF, COX-2, and TLR-2) was evaluated by reverse transcription and quantitative PCR. Transcription (ΔΔCT) of most measured factors was induced in challenged bMEC for 6 and 24 h. Interestingly, relative mRNA levels were higher (P