title: Effects of cyclosporin A induced T-lymphocyte depletion on the course of avian Metapneumovirus (aMPV) infection in turkeys.
abstract: The avian Metapneumovirus (aMPV) causes an economically important acute respiratory disease in turkeys (turkey rhinotracheitis, TRT). While antibodies were shown to be insufficient for protection against aMPV-infection, the role of T-lymphocytes in the control of aMPV-infection is not clear. In this study we investigated the role of T-lymphocytes in aMPV-pathogenesis in a T-cell-suppression model in turkeys. T-cell-intact turkeys and turkeys partly depleted of functional CD4(+) and CD8(+) T-lymphocytes by Cyclosporin A (CsA) treatment were inoculated with the virulent aMPV subtype A strain BUT 8544. CsA-treatment resulted in a significant reduction of absolute numbers of circulating CD4(+) and CD8alpha(+) T-lymphocytes by up to 82 and 65%, respectively (P<0.05). Proportions of proliferating T-cells within mitogen-stimulated peripheral blood mononuclear cells were reduced by similar levels in CsA-treated birds compared to untreated controls (P<0.05). CsA-treated turkeys showed delayed recovery from aMPV-induced clinical signs and histopathological lesions and a prolonged detection of aMPV in choanal swabs. The results of this study show that T-lymphocytes play an important role in the control of primary aMPV-infection in turkeys.
authors.affiliation: Clinic for Poultry, University of Veterinary Medicine Hannover, Bünteweg 17, Hannover, Germany.
authors.forename: Dennis
authors.initials: D
authors.lastname: Rubbenstroth
authors.forename: Tina S
authors.initials: TS
authors.lastname: Dalgaard
authors.forename: Sonja
authors.initials: S
authors.lastname: Kothlow
authors.forename: Helle R
authors.initials: HR
authors.lastname: Juul-Madsen
authors.forename: Silke
authors.initials: S
authors.lastname: Rautenschlein
mesh_terms: D000818:Animals; D015704:CD4 Antigens / Q000096:biosynthesis; D016827:CD8 Antigens / Q000096:biosynthesis; D002452:Cell Count; D049109:Cell Proliferation / Q000187:drug effects; D016572:Cyclosporine / Q000008:administration & dosage; D007111:Immunity, Cellular; D008212:Lymphocyte Depletion; D029121:Metapneumovirus / Q000276:immunology* / Q000472:pathogenicity; D018184:Paramyxoviridae Infections / Q000097:blood / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology; D014422:Turkeys
chemical_list: D015704:CD4 Antigens; D016827:CD8 Antigens; D016572:Cyclosporine