Comparative analysis of signature genes in Porcine Reproductive and Respiratory Syndrome Virus (PRRSV)-infected porcine monocyte-derived dendritic cells at differential activation statuses.

Activation statuses of monocytic cells, e.g. monocytes, macrophages and dendritic cells (DCs), are critically important for antiviral immunity. In particular, some devastating viruses, including porcine reproductive and respiratory syndrome virus (PRRSV), are capable of directly infecting these cells to subvert host immunity. Monocyte-derived DCs (mDCs) are major target cells in PRRSV pathogenesis; however, the plasticity of mDCs in response to activation stimuli and PRRSV infection remains unstudied. In this study, we polarized mDCs, and applied genome-wide transcriptomic analysis to compare signature genes involved in mDCs activation and response to PRRSV infection. Our long-term goal is to integrate activation status with antiviral responses in these cells and to functionally modulate them for a prototypic cellular adjuvant/vaccine that is ideal for potentiating antiviral immunity. Porcine mDCs were polarized with mediators for 30 hours, then mock-infected, infected with PRRSV strain VR2332, or a highly pathogenic PRRSV strain (rJXwn06), for 5 h. Total RNA was extracted and used to construct sequencing libraries for RNA-Seq procedures previously optimized. Comparisons were made between each polarized and unpolarized group (i.e. mediator vs. PBS), and between PRRSV-infected and uninfected cells stimulated with the same mediator. Many of the genes showing the most variability were related to cellular structure and innate immune response. The magnitude of differentially expressed gene profiles detected in HP-PRRSV rJXwn06 infected mDCs as compared to VR-2332 infected mDCs was consistent with the increased pathogenicity of the HP-PRRSV in vivo .