title: Early host response in the mammary gland after experimental Streptococcus uberis challenge in heifers.
abstract: Streptococcus uberis is a highly prevalent causative agent of bovine mastitis, which leads to large economic losses in the dairy industry. The aim of this study was to examine the host response during acute inflammation after experimental challenge with capsulated Strep. uberis. Gene expression in response to Strep. uberis was compared between infected and control quarters in 3 animals. All quarters (n=16) were sampled at 16 different locations. Microarray data showed that 239 genes were differentially expressed between infected and control quarters. No differences in gene expression were observed between the different locations. Microarray data were confirmed for several genes using quantitative PCR analysis. Genes differentially expressed due to early Strep. uberis mastitis represented several stages of the process of infection: (1) pathogen recognition; (2) chemoattraction of neutrophils; (3) tissue repair mechanisms; and (4) bactericidal activity. Three different pathogen recognition genes were induced: ficolins, lipopolysaccharide binding protein, and toll-like receptor 2. Calgranulins were found to be the most strongly upregulated genes during early inflammation. By histology and immunohistochemistry, we demonstrated that changes in gene expression in response to Strep. uberis were induced both in infiltrating somatic milk cells and in mammary epithelial cells, demonstrating that the latter cell type plays a role in milk production as well as immune responsiveness. Given the rapid development of inflammation or mastitis after infection, early diagnosis of (Strep. uberis) mastitis is required for prevention of disease and spread of the pathogen. Insight into host responses could help to design immunomodulatory therapies to dampen inflammation after (early) diagnosis of Strep. uberis mastitis. Future research should focus on development of these early diagnostics and immunomodulatory components for mastitis treatment.
authors.affiliation: Central Veterinary Institute of Wageningen University and Research Centre, Edelhertweg 15, 8219 PH Lelystad, The Netherlands. astrid.degreeff@wur.nl
authors.forename: Astrid
authors.initials: A
authors.lastname: de Greeff
authors.forename: Ruth
authors.initials: R
authors.lastname: Zadoks
authors.forename: Lisette
authors.initials: L
authors.lastname: Ruuls
authors.forename: Mathilda
authors.initials: M
authors.lastname: Toussaint
authors.forename: Thi Kim Anh
authors.initials: TK
authors.lastname: Nguyen
authors.forename: Alison
authors.initials: A
authors.lastname: Downing
authors.forename: Johanna
authors.initials: J
authors.lastname: Rebel
authors.forename: Norbert
authors.initials: N
authors.lastname: Stockhofe-Zurwieden
authors.forename: Hilde
authors.initials: H
authors.lastname: Smith
mesh_terms: D000209:Acute-Phase Proteins / Q000235:genetics; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics; D002417:Cattle; D002452:Cell Count; D004847:Epithelial Cells / Q000276:immunology; D005260:Female; D015870:Gene Expression; D006801:Humans; D007249:Inflammation / Q000276:immunology / Q000382:microbiology; D037102:Lectins / Q000235:genetics; D008321:Mammary Glands, Animal / Q000276:immunology / Q000382:microbiology* / Q000473:pathology; D008414:Mastitis, Bovine / Q000276:immunology / Q000378:metabolism / Q000382:microbiology*; D008562:Membrane Glycoproteins / Q000235:genetics; D046228:Microarray Analysis / Q000662:veterinary; D008892:Milk / Q000166:cytology; D016133:Polymerase Chain Reaction / Q000662:veterinary; D013290:Streptococcal Infections / Q000276:immunology / Q000378:metabolism / Q000662:veterinary*; D013291:Streptococcus / Q000276:immunology*; D051195:Toll-Like Receptor 2 / Q000235:genetics; D000097604:Ficolins; D000099231:Lipopolysaccharide-Binding Protein
chemical_list: D000209:Acute-Phase Proteins; D002352:Carrier Proteins; D037102:Lectins; D008562:Membrane Glycoproteins; D051195:Toll-Like Receptor 2; D000097604:Ficolins; D000099231:Lipopolysaccharide-Binding Protein