Transcriptomic Analysis of Host Immune Response in the Skin of Chickens Infected with Marek's Disease Virus

Marek's disease virus (MDV), a highly cell-associated oncogenic α-herpesvirus, is the causative agent of T cell lymphoma and neuropathic disease called Marek's disease. The skin is the only anatomical site where infectious enveloped cell-free virions are produced and shed into the environment. Studies have demonstrated that MDV infection induces immunological responses within the skin, including the release of cytokines and the recruitment of T lymphocytes. The host immune response, however, is not sufficient to block replication and shedding of the virus particles from the skin. In this study, we examined the gene expression profiling in the skin tissues of MDV-infected chickens to identify viral-induced alterations in the host gene expression pattern. To identify these genes in an unbiased and comprehensive manner, we performed RNA-seq on skin samples of MDV-infected chickens at 10, 20, and 30 days postinfection (dpi). We identified 820, 1,333, and 1,571 upregulated genes in the skin of MDV-infected chickens at 10, 20, and 30 dpi, respectively. In addition, we identified 461, 878, and 1,751 downregulated genes corresponding to the same time points, respectively. Analysis of the upregulated genes resulted in the identification of multiple gene ontology (GO) categories, with most falling under the host immune response. Searching these immune related GO categories, we identified six genes, gga-let-7d, interleukin 22 receptor subunit alpha 2, tumor necrosis factor receptor superfamily member 21, Proline-serine-threonine phosphatase-interacting protein 2, Suppressor of cytokine signaling (SOCS)1, and SOCS3, with known immunosuppressive properties that are upregulated in the skin of MDV-infected chickens.