Marek's disease virus (MDV), a highly transmissible cell-associated neuropathic oncogenic alpha herpes virus affecting poultry health, resulting in considerable economic losses in poultry industry worldwide.Until now MDV still emerging and re emerging causing great economic losses in chicken despite intensive vaccination and management policy used in poultry farms. However, cytokines and its role in MD pathogenesis and immunity had been described by some workers under certain experimental conditions by using different MDV strains challenge, they need to be more clarified during the more progressive lymphoma transformation stage. The present study aimed to examine the transcriptional profiling of a panel of cytokines genes in the splenic tissues of special broiler Japanese chickens (70-80 days old) contracted natural infection with MDV despite intensive care and vaccination policy adopted by HVT and CVI988/Rispene. SYBR Green-based, real-time (RT)-PCR protocol was used to quantitate cytokine mRNA in freshly collected spleen tissue of MDV infected and control chicken. Changes in the levels of spleen interleukins (IL) as IL-6, IL-10, IL- 18 and IL-12P35, IL-4, interferon-gamma (IFN-γ) and inducible nitric oxide synthase (iNOS) mRNA was determined. Relative Messenger RNA (mRNA) expression levels of the above-mentioned genes, and β-actin as a reference gene were achieved. The results of quantitative real-time PCR (qPCR) assays using revealed significant up regulation in the expression levels of IL-6, IL-10, IL-18, and IL-12P35). The changes in the mRNA levels of IL-4, IFN-γ and inducible nitric oxide synthesase (iNOS) were minimal and not significant in comparison to those in uninfected age-matched control chicken. In conclusion, these data strongly support the hypothesis that pro-inflammatory responses, including high levels of Th2 cytokines as IL-10 and other interleukins as IL-6, IL-18 and IL12-P35, may play a major role during MDV lymphoma transformation stage induced by MDV strain of high virulence. These cytokines may be involved in the maintenance of MDV infection and lymphoma formation. On the other hand, Th1 cytokines as IFN-γ, and iNOS had no or minimal role in the induction of MDV-specific immune response during MDV lymphoma transformation stage.
Keywords: MDV; lymphoma, Cytokine; Th1; Th2; q-PCR.
Abstract published in IOSR Journal of Agriculture and Veterinary Science (IOSR-JAVS) e-ISSN: 2319-2380, p-ISSN: 2319-2372. Volume 10, Issue 1 Ver. I (January. 2017), PP 72-80.