title: Shifted T Helper Cell Polarization in a Murine Staphylococcus aureus Mastitis Model.
abstract: Mastitis, one of the most costly diseases in dairy ruminants, is an inflammation of the mammary gland caused by pathogenic infection. The mechanisms of adaptive immunity against pathogens in mastitis have not been fully elucidated. To investigate T helper cell-mediated adaptive immune responses, we established a mastitis model by challenge with an inoculum of 4 × 106 colony-forming units of Staphylococcus aureus in the mammary gland of lactating mice, followed by quantification of bacterial burden and histological analysis. The development of mastitis was accompanied by a significant increase in both Th17 and Th1 cells in the mammary gland. Moreover, the relative expression of genes encoding cytokines and transcription factors involved in the differentiation and function of these T helper cells, including Il17, Rorc, Tgfb, Il1b, Il23, Ifng, Tbx21, and Il12, was greatly elevated in the infected mammary gland. IL-17 is essential for neutrophil recruitment to infected mammary gland via CXC chemokines, whereas the excessive IL-17 production contributes to tissue damage in mastitis. In addition, a shift in T helper cell polarization toward Th2 and Treg cells was observed 5 days post-infection, and the mRNA expression of the anti-inflammatory cytokine Il10 was markedly increased at day 7 post-infection. These results indicate that immune clearance of Staphylococcus aureus in mastitis is facilitated by the enrichment of Th17, Th1 and Th2 cells in the mammary gland mediated by pro-inflammatory cytokine production, which is tightly regulated by Treg cells and the anti-inflammatory cytokine IL-10.
authors.affiliation: College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi Province, People's Republic of China.
authors.forename: Yanqing
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi Province, People's Republic of China.
authors.forename: Ming
authors.initials: M
authors.lastname: Zhou
authors.affiliation: College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi Province, People's Republic of China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Gao
authors.affiliation: College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi Province, People's Republic of China.
authors.forename: Heyuan
authors.initials: H
authors.lastname: Liu
authors.affiliation: College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi Province, People's Republic of China.
authors.forename: Wenyu
authors.initials: W
authors.lastname: Yang
authors.affiliation: College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi Province, People's Republic of China.
authors.forename: Jinhua
authors.initials: J
authors.lastname: Yue
authors.affiliation: College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi Province, People's Republic of China.
authors.forename: Dekun
authors.initials: D
authors.lastname: Chen
mesh_terms: D000818:Animals; D016764:Cell Polarity; D016207:Cytokines / Q000235:genetics; D005260:Female; D005786:Gene Expression Regulation; D008413:Mastitis / Q000276:immunology* / Q000382:microbiology; D051379:Mice; D008810:Mice, Inbred C57BL; D013211:Staphylococcus aureus / Q000302:isolation & purification*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology* / Q000378:metabolism
chemical_list: D016207:Cytokines