title: Immune responses associated with progression and control of infection in calves experimentally challenged with Mycobacterium avium subsp. paratuberculosis.
abstract: This study examined the immune responses related to the infection, progression and control of Mycobacterium avium subsp. paratuberculosis (MAP) infection in calves. Twenty calves were challenged orally with MAP and 11 non-challenged calves served as controls. Approximately half the calves from each group were sacrificed at either 7 or 15 months post-challenge (PC). The majority of the challenged calves (19/20) shed MAP in feces 2-4 months PC, but thereafter fecal shedding reduced markedly. The severity of infection was reduced at 15 months PC compared to that at 7 months PC as seen from a significantly lower isolation of MAP from tissues and lower lesion scores (P<0.05). In addition, there was a reduction in the upregulation of gene expression of gamma interferon, interleukin-10 (IL-10) and inducible nitric oxide synthase from the antigen-stimulated mesenteric lymph node (MLN) cultures of the challenged calves. No evidence of infection was detected in the control calves. The severity of the infection in individual calves at 15 months PC as indicated from the number of tissue culture positive sites, was negatively related to IL-10 released from antigen-stimulated peripheral blood mononuclear cells (P<0.05). Collectively the data indicated that the severity of the MAP infection was reduced in the calves at 15 months PC and in a specific time period during infection, IL-10 may play a role in reducing the severity of this disease.
authors.affiliation: AgResearch, Hopkirk Research Institute, Grasslands Research Centre, Private Bag 11008, Palmerston North 4442, New Zealand.
authors.forename: Supatsak
authors.initials: S
authors.lastname: Subharat
authors.forename: Dairu
authors.initials: D
authors.lastname: Shu
authors.forename: D Neil
authors.initials: DN
authors.lastname: Wedlock
authors.forename: Marian
authors.initials: M
authors.lastname: Price-Carter
authors.forename: Geoffrey W
authors.initials: GW
authors.lastname: de Lisle
authors.forename: Dongwen
authors.initials: D
authors.lastname: Luo
authors.forename: Desmond M
authors.initials: DM
authors.lastname: Collins
authors.forename: Bryce M
authors.initials: BM
authors.lastname: Buddle
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology* / Q000382:microbiology*; D005243:Feces / Q000382:microbiology; D005260:Female; D007371:Interferon-gamma / Q000276:immunology; D016753:Interleukin-10 / Q000276:immunology; D008198:Lymph Nodes / Q000276:immunology / Q000382:microbiology; D016927:Mycobacterium avium subsp. paratuberculosis / Q000235:genetics / Q000276:immunology*; D052247:Nitric Oxide Synthase Type II / Q000276:immunology; D010283:Paratuberculosis / Q000276:immunology* / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics; D011897:Random Allocation; D018709:Statistics, Nonparametric
chemical_list: D012333:RNA, Messenger; D016753:Interleukin-10; D007371:Interferon-gamma; D052247:Nitric Oxide Synthase Type II