Whole blood transcriptome comparison of pigs with extreme production of in vivo dsRNA-induced serum IFN-a.

Interferon (IFN) is one of the major regulators of innate immunity, it also mediates the adaptive immune responses to a broad spectrum of pathogens. This study aims in identifying differences between high vs. low INF-a responders which were chosen based on serum INF-a levels at 4 h post poly I:C treatment. A transcriptomic analysis was designed to describe the whole blood differential transcriptomal response to poly I:C by pigs with high vs. low IFN alpha levels. The capability of producing dsRNA (poly I:C)-induced serum IFN-a is highly variable in pig population. The high INF-a responders had 328 unique differentially expressed genes, suggesting that the HIGH pigs have greater responsiveness upon the dsRNA simulation. Based on the results, the interferon-dependent antiviral responsiveness through the IFN-stimulated genes (ISGs) is likely more effective in HIGH pigs. Inferring from the known organization of IFN pathways, the reason for the more IFN-a production in the HIGH pigs was likely due to the enhanced expression of IRF-7 in TLR or RIG- I/MDA5 signaling pathways. Furthermore, the larger number of the altered genes in the HIGH pigs after simulation is also possibly because of the greater number of the altered transcription factors. To our knowledge, this is the first report of comparative transcriptomic analysis to advance our understanding of whole blood immune response in pigs with different in vivo poly I:C-inducted IFN-a levels. The paper significantly expands our knowledge of how pigs respond to poly I:C which is highly relevant for understanding resistance to viral infections and also for vaccine development.