title: Peripheral cellular and humoral responses to infestation with the cattle tick Rhipicephalus microplus in Santa Gertrudis cattle.
abstract: Resistance to cattle tick infestation in single-host ticks is primarily manifested against the larval stage and results in the immature tick failing to attach successfully and obtain a meal. This study was conducted to identify immune responses that characterize the tick-resistant phenotype in cattle. Thirty-five tick-naïve Santa Gertrudis heifers were used in this study, thirty of which were artificially infested for thirteen weeks with tick larvae while five animals remained at a tick-free quarantine property to serve as a control group. Following thirteen weeks of tick infestation, the animals in this trial exhibited highly divergent tick-resistant phenotypes. Blood samples collected throughout the trial were used to measure peripheral immune parameters: haematology, the percentage of cellular subsets comprising the peripheral blood mononuclear cell (PBMC) population, tick-specific IgG1and IgG2antibody titres, IgG1 avidity for tick antigens and the ability of PBMC to recognize and proliferate in response to stimulation with tick antigens in vitro. The tick-susceptible cattle developed significantly higher tick-specific IgG1antibody titres compared to the tick-resistant animals. These results suggest that the heightened antibody response either does not play a role in resistance or might contribute to increased susceptibility to infestation.
authors.affiliation: The University of Queensland, School of Veterinary Science, Gatton, Qld, Australia.
authors.forename: E K
authors.initials: EK
authors.lastname: Piper
authors.affiliation: The University of Glasgow, Institute of Biodiversity, Animal Health and Comparative Medicine, Glasgow, G61 1QH, UK.
authors.forename: N N
authors.identifier: 0000-0003-3245-9783
authors.initials: NN
authors.lastname: Jonsson
authors.affiliation: The University of New England, The Centre for Genetic Analysis and Applications, Armidale, NSW, Australia.
authors.forename: C
authors.initials: C
authors.lastname: Gondro
authors.affiliation: Department of Agriculture and Fisheries, Biosecurity Science Laboratories, Brisbane, Qld, Australia.
authors.forename: M E
authors.identifier: 0000-0001-5824-1008
authors.initials: ME
authors.lastname: Vance
authors.affiliation: Department of Agriculture and Fisheries, Biosecurity Science Laboratories, Brisbane, Qld, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Lew-Tabor
authors.affiliation: Department of Agriculture and Fisheries, Biosecurity Science Laboratories, Brisbane, Qld, Australia.
authors.forename: L A
authors.initials: LA
authors.lastname: Jackson
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology*; D005260:Female; D007111:Immunity, Cellular; D056724:Immunity, Humoral; D007963:Leukocytes, Mononuclear; D048494:Rhipicephalus / Q000276:immunology* / Q000502:physiology; D013984:Tick Infestations / Q000276:immunology / Q000662:veterinary*
keywords:  Rhipicephalus microplus ; cattle; immune response; tick