title: Immunosuppression in sheep induced by cyclophosphamide, bluetongue virus and their combination: Effect on clinical reaction and viremia.
abstract: The main purpose of this work was to establish an experimental model for immunosuppression in sheep, and evaluate its possible effects on bluetongue viremia. Animals were allocated in 4 groups: Cy (cyclophosphamide), BT (bluetongue), CyBT (combined Cy and BT) and Co (control), and underwent clinical evaluations, virological testing, peripheral blood immunophenotyping and determination of antiviral humoral immune responses. Intravenous administration of cyclophosphamide (37.5 mg/kg body weight) resulted in immunosuppresion induction, as significant drops were observed in blood leukocytes and lymphocyte subset counts (CD2+, CD4+, CD8+, CD19+), lasting 3-10 days after its administration. Reduction in B-cell (CD19+) counts was more pronounced than in T-/NK-cell (CD2+) counts (92% and 59%, respectively). BTV-9 inoculation resulted in pronounced lymphocytopenia observed from day 1 post-inoculation. Their combined administration resulted in a more intense immunosuppressive effect, as indicated by the greater reduction in lymphocyte, granulocyte, CD4+and CD8+cell counts. In group CyBT, earlier initiation of fever by one day (day 6 p.i.) compared to group BT (day 7 p.i.), and delay in antibody responses by one day was observed, compared to group BT. Neutralizing antibodies in both groups (BT, CyBT) were detectable from day 10 p.i., but no significant titer differences were observed. Infectious virus titers were detected from day 4 p.i. in group BT and from day 3 in group CyBT. Statistical significances in virus titers were also observed (greatest mean titer difference: 1.4 log10CEID50/ml RBCs at day 5 p.i., P < 0.001), indicating possible impact of immunosuppression on virus transmission and epidemiology of bluetongue.
authors.affiliation: Laboratory of Microbiology and Infectious Diseases, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, University Campus, 54124, Thessaloniki, Greece.
authors.forename: Evangelia
authors.initials: E
authors.lastname: Chatzinasiou
authors.affiliation: Diagnostic Laboratory, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, 11 Stavrou Voutyra str., 54627, Thessaloniki, Greece.
authors.forename: Serafeim C
authors.initials: SC
authors.lastname: Chaintoutis
authors.affiliation: Diagnostic Laboratory, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, 11 Stavrou Voutyra str., 54627, Thessaloniki, Greece.
authors.forename: Chrysostomos I
authors.initials: CI
authors.lastname: Dovas
authors.affiliation: Laboratory of Microbiology and Infectious Diseases, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, University Campus, 54124, Thessaloniki, Greece. Electronic address: mpapanas@vet.auth.gr.
authors.forename: Maria
authors.initials: M
authors.lastname: Papanastassopoulou
authors.affiliation: Laboratory of Microbiology and Infectious Diseases, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, University Campus, 54124, Thessaloniki, Greece.
authors.forename: Orestis
authors.initials: O
authors.lastname: Papadopoulos
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D001819:Bluetongue / Q000276:immunology / Q000821:virology*; D001820:Bluetongue virus / Q000254:growth & development* / Q000276:immunology / Q000302:isolation & purification; D003520:Cyclophosphamide / Q000008:administration & dosage*; D007108:Immune Tolerance; D007165:Immunosuppression Therapy; D007166:Immunosuppressive Agents / Q000008:administration & dosage*; D007958:Leukocyte Count; D016131:Lymphocyte Subsets / Q000276:immunology; D012756:Sheep; D019562:Viral Load; D014766:Viremia
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D007166:Immunosuppressive Agents; D003520:Cyclophosphamide
keywords: B-cells; Bluetongue virus; Clinical sign; Cyclophosphamide; Humoral immune response; Immunosuppression; Neutralizing antibody; Sheep; T-cells; Viremia