Host responses in the bursa of Fabricius of chickens infected with virulent Marek's disease virus

Authors: ABDUL-CAREEM, M - UNIV OF GUELPH - CANADA; HUNTER, B - UNIV OF GUELPH - CANADA; Lee, Lucy; FAIRBROTHER, J - UNIVERSITE DE MONTREAL; HAGHIGHI, H - UNIV OF GUELPH - CANADA; READ, L - UNIV OF GUELPH - CANADA; PARVIZI, P - University Of Guelph; Heidari, Mohammad; SHARIF, S - UNIV OF GUELPH - CANADA

Submitted to: Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/24/2008
Publication Date: 9/30/2008
Citation: Abdul-Careem, M.F., Hunter, B.D., Lee, L.F., Fairbrother, J.H., Haghighi, H.R., Read, L., Parvizi, P., Heidari, M., Sharif, S. 2008. Host Responses in the Bursa of Fabricius of Chickens Infected with Virulent Marek's Disease Virus. Virology. 379(2):256-265.

Interpretive Summary: Marek’s disease (MD) causes major economical losses to the poultry industry in the United States and around the world. Marek’s disease virus (MDV) actively replicates in one type of immune cells known as B cells during the first 7 days of infection, this is followed by a dormant stage of infection in a second type of immune cells known as T cells. In this study, we evaluated the expression of several host immune related genes associated with a very virulent MDV infection in the bursa of Fabricius (BF), a central lymphoid organ in the chicken that is responsible for B-cell immune response. Of the immune related genes examined, three genes named interferon (IFN)-alpha, IFN-gamma, and nitric oxide synthase were highly up regulated in response to MDV infection in BF. The information obtained in this study provides insight into the molecular mechanism of immune responses in the BF; it should be of great interest to scientists in the academia and industry, who are interested in studying the pathogenicity and control of this important virus infection of chickens.

Technical Abstract: Host responses associated with very virulent Marek’s disease virus (MDV) infection in the bursa of Fabricius of chicken was investigated. The expression of MDV pp38 antigen and MDV gB transcripts were higher at 4 days post-infection (dpi) and then showed a declining trend. On the contrary, the expression of MDV meq gene, which was known to be associated more with the latency, and the viral genome load were increased gradually towards the end of the study period (14 dpi). The changes in viral parameters were associated with significantly higher infiltration of macrophages at 4 and 7 dpi and the significant increase in T cell subsets, particularly CD4+ T cells into the bursa of Fabricius during most of the observations. Of the cytokine genes examined, the expression of interferon (IFN)-alpha and IFN-gamma genes as well as inducible nitric oxide synthase (iNOS) were up regulated significantly in response to MDV infection in bursa of Fabricius. The results suggest a role of these cells and cytokines in MDV induced host responses in bursa of Fabricius.