ARS | Publication request: Immunological Basis for Resistance and Susceptibility to Marek's Disease

Submitted to: American Veterinary Medical Association Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 11, 2009
Publication Date: July 11, 2009
Citation: Heidari, M. 2009. Immunological Basis for Resistance and Susceptibility to Marek's Disease [abstract]. In: 146th American Veterinary Medical Association Convention Notes, July 11-14, 2009, Seattle, Washington. Paper No. 7658

Technical Abstract: Marek’s disease (MD) is a contagious lymphoproliferative disease of domestic chickens caused by a highly cell-associated alpha-herpesvirus, Marek’s disease virus (MDV). MDV replicates in chicken lymphocytes and establishes a latent infection within CD4+ T cells. Mechanisms of viral pathogenesis, resistance to MDV infection/oncogenesis, and the protection process of attenuated vaccine strains are poorly understood. Clearly, a complex set of interactions between viral genes and host’s immune responses are involved. To better understand the molecular mechanisms overriding these events, the expression pattern of cytokines, chemokines, and other immune related genes were investigated between MDV-infected chickens of lines 63 (MD-resistant) and 72 (MD-susceptible). Real-Time PCR analysis revealed high expression levels of IL-1ß, IL-6, IL-8, iNOS, IFNß, IFNgamma, and IFNlambda in the spleen tissues of MDV-infected susceptible chickens when compared to un-infected control birds. In contrast, only a limited number of cytokines were up-regulated in the MDV-inoculated resistant chickens (IL-6, IL12-p35, IFNgamma, and IFNlambda). In addition, immunohistochemical analysis showed an extensive infection and inflammation in the bursa and spleen tissues of MDV-infected birds from line 72. No infection was observed in the tissues of MDV-inoculated chickens from line 63. This study reveals significant differences in immunological responses to MD between the resistant and susceptible lines.