title: Characterization of the bovine innate immune response in milk somatic cells following intramammary infection with Streptococcus dysgalactiae subspecies dysgalactiae.
abstract: The innate immune response of milk somatic cells in cows to Streptococcus dysgalactiae ssp. dysgalactiae was investigated by deliberate intramammary challenge. Cows were challenged with 2,500 colony-forming units of Strep. dysgalactiae DPC 5435, previously isolated from a clinical mastitis case. Eight of the 9 cows treated showed clinical signs of mastitis (swollen udders, increased somatic cell score, and clotted milk) within 1 wk of challenge. Messenger RNA levels of IL-1β and toll-like receptor 4 (TLR4) in milk somatic cells increased approximately 40 fold within 48 h of infusion, whereas tumor necrosis factor α increased 16 fold within the same time frame. Interestingly, cows homozygous for the G allele of the C-X-C chemokine receptor type 1 (CXCR1)-777 polymorphism had higher IL-8 and CXCR1 transcript abundance at 24h postinfusion compared with cows homozygous for the C allele. The difference in expression of these genes at this critical time point may influence the severity of disease within different genotypes.
authors.affiliation: Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork, Ireland.
authors.forename: C
authors.initials: C
authors.lastname: Beecher
authors.forename: M
authors.initials: M
authors.lastname: Daly
authors.forename: R P
authors.initials: RP
authors.lastname: Ross
authors.forename: J
authors.initials: J
authors.lastname: Flynn
authors.forename: T V
authors.initials: TV
authors.lastname: McCarthy
authors.forename: L
authors.initials: L
authors.lastname: Giblin
mesh_terms: D000818:Animals; D002417:Cattle; D016207:Cytokines / Q000502:physiology; D005260:Female; D005838:Genotype; D007113:Immunity, Innate / Q000276:immunology*; D008414:Mastitis, Bovine / Q000276:immunology* / Q000382:microbiology; D008892:Milk / Q000166:cytology / Q000276:immunology*; D023062:Receptors, Interleukin-8A / Q000235:genetics / Q000502:physiology; D013290:Streptococcal Infections / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D013291:Streptococcus / Q000276:immunology
chemical_list: D016207:Cytokines; D023062:Receptors, Interleukin-8A