Viral/Host Gene Expression Profiles in Lymphoid and Feather Follicle Epithelial (FFE) Cells Infected with Marek’s Disease Virus (MDV)”.

Marek’s disease virus (MDV) is highly infectious herpesvirus that induces rapid-onset malignant T-cell lymphoma in the chicken. While the virus remains latent in the lymphocytes, it replicates in the feather follicle epithelial (FFE) cells and spread via the chicken respiratory track after inhalation of contaminated dust to continue the life cycle. The gene expression study in the lymphoid cells and FFE can provide significant insights into the unique virus-host interactions in these two distinct sites of virus replication. Chickens were infected intra-abdominally at 8 days of age with a modified RB-1B virus expressing enhanced green fluorescent protein (EGFP) ad observed for the occurrence of MD. The EGFP marker was used to track the virus infection in different cell types. Tissue samples from spleen, kidney and liver were collected for transcriptome analysis. The skin samples collected as frozen cryoblocks were used to make thin cryosections to demonstrate the expression of viral proteins.  The Laser micro-dissection (LMD) was also used to isolate infected EHFP-positive infected cells and extraction of RNA for transcriptome analysis. All the samples are sequenced using Illumina HiSeq2500. The reads were mapped to host and virus using Tophat and gene expression levels were measured using HTseq-count. Differentially expressed genes between infected FFE and control as well as infected lymphoid and control were identified using edgeR. Ingenuity pathway analysis (IPA) tool recognized the functions and pathways of differentially expressed genes. Consequences on differentially expressed host and viral genes between the infected FFE and lymphoid and their potential role in virus-host interactions will be presented.