title: Bovine natural killer cells are present in Escherichia coli infected mammary gland tissue and show antimicrobial activity in vitro.
abstract: Natural killer (NK) cells are early responders in bacterial infections but their role in bovine mastitis has not been characterized. For the first time, we show the presence of NK cells (NKp46(+)/CD3(-)) in bovine mammary gland tissue after an intramammary challenge with Escherichia (E.) coli. A small number of NK cells was detected in milk from quarters before and during an E. coli challenge. In vitro cultures of primary bovine mammary gland epithelial cells stimulated with UV irradiated E. coli induced significant migration of peripheral blood NK cells (pbNK) within 2h. Furthermore, pbNK cells significantly reduced counts of live E. coli in vitro within 2h of culture. The results show that bovine NK cells have the capacity to migrate to the site of infection and produce antibacterial mediators. These findings introduce NK cells as a leukocyte population in the mammary gland with potential functions in the innate immune response in bovine mastitis.
authors.affiliation: Quality Milk Production Services, Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA. Electronic address: ass233@cornell.edu.
authors.forename: Anja
authors.initials: A
authors.lastname: Sipka
authors.affiliation: Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
authors.forename: Brianna
authors.initials: B
authors.lastname: Pomeroy
authors.affiliation: Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Klaessig
authors.affiliation: Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA; GD Animal Health, Deventer, the Netherlands; Department of Animal Science, Wageningen University, Wageningen, the Netherlands.
authors.forename: Ynte
authors.initials: Y
authors.lastname: Schukken
mesh_terms: D000818:Animals; D058491:Bacterial Load; D002417:Cattle; D054441:Cell Migration Assays, Leukocyte; D004847:Epithelial Cells / Q000382:microbiology; D004926:Escherichia coli / Q000276:immunology* / Q000502:physiology; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary*; D005260:Female; D007113:Immunity, Innate; D007694:Killer Cells, Natural / Q000276:immunology*; D008321:Mammary Glands, Animal / Q000276:immunology / Q000382:microbiology; D008414:Mastitis, Bovine / Q000276:immunology* / Q000382:microbiology; D008892:Milk / Q000166:cytology / Q000276:immunology
keywords: Bovine mastitis; E. coli; Innate immunity; Mammary gland epithelial cells; NK cells