title: Cytokine expression by neutrophils of adult horses stimulated with virulent and avirulent Rhodococcus equi in vitro.
abstract: Rhodococcus equi is an intracellular pathogen of macrophages that causes rhodococcal pneumonia in foals and immunocompromised people. Evidence exists that neutrophils play a vital role in resistance to infection with R. equi; however, the means by which neutrophils exert their effects have not been clearly defined. In addition to directly killing bacteria, neutrophils also may exert a protective effect by linking innate and adaptive immune responses. In the present study we evaluated the cytokine expression profiles of adult equine neutrophils in response to stimulation with isogenic strains of virulent and avirulent R. equi in vitro. After 2 and 4h incubation with virulent or avirulent R. equi, adult equine neutrophils expressed significantly (P<0.05) greater tumor necrosis factor alpha (TNFalpha), interleukin (IL)-12p40, IL-6, IL-8 and IL-23p19 mRNA, but not interferon gamma (IFNgamma) or IL-12p35 mRNA than unstimulated neutrophils. Furthermore, virulent R. equi induced significantly greater IL-23p19 mRNA than avirulent R. equi. These results demonstrate that R. equi-stimulated neutrophils are a source of many proinflammatory cytokines. Furthermore, these results suggest that IL-23 may be preferentially expressed over IL-12 in response to exposure with R. equi, and that this response may be more strongly induced by virulent R. equi than avirulent R. equi. Collectively, the data presented herein suggest a non-phagocytic role for neutrophils that may influence the type of adaptive immune response to R. equi.
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843-4475, USA.
authors.forename: Jessica R
authors.initials: JR
authors.lastname: Nerren
authors.forename: Susan
authors.initials: S
authors.lastname: Payne
authors.forename: Natalie D
authors.initials: ND
authors.lastname: Halbert
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Martens
authors.forename: Noah D
authors.initials: ND
authors.lastname: Cohen
mesh_terms: D000193:Actinomycetales Infections / Q000235:genetics / Q000276:immunology / Q000662:veterinary; D000818:Animals; D001483:Base Sequence; D016207:Cytokines / Q000235:genetics*; D017931:DNA Primers / Q000235:genetics; D015870:Gene Expression; D020869:Gene Expression Profiling; D006734:Horse Diseases / Q000235:genetics / Q000276:immunology; D006736:Horses / Q000235:genetics* / Q000276:immunology*; D066298:In Vitro Techniques; D053762:Interleukin-12 Subunit p40 / Q000235:genetics; D053760:Interleukin-23 Subunit p19 / Q000235:genetics; D015850:Interleukin-6 / Q000235:genetics; D016209:Interleukin-8 / Q000235:genetics; D009504:Neutrophils / Q000276:immunology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016929:Rhodococcus equi / Q000276:immunology* / Q000472:pathogenicity*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics; D014774:Virulence / Q000276:immunology
chemical_list: D016207:Cytokines; D017931:DNA Primers; D053762:Interleukin-12 Subunit p40; D053760:Interleukin-23 Subunit p19; D015850:Interleukin-6; D016209:Interleukin-8; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha