Comparative analyses of PBMC transcriptome profiles between German Landrace and Pietrain pigs following PRRSV vaccination

Porcine reproductive and respiratory syndrome (PRRS) is a devastating viral disease affecting swine industry worldwide. Innate immune response to PRRS virus (PRRSV) infection varies among pig breeds. Elucidating the role of host genetics in the variation of PRRSV vaccine responsiveness may lead to characterize the host immunocompetence and thereby resistance to PRRS. Therefore, the current study aimed to investigate the breed difference in innate immune response to PRRSV vaccination between German Landrace (DL) and Pietrain (Pi) pigs.

We employed a total of 12 Affymetrix GeneChip porcine gene 1.0 ST array for transcriptome profiling of peripheral blood mononuclear cells (PBMCs) collected before (0h) and 24h after PRRSV vaccination from three female piglets of four weeks old from both DL and Pi breed. Normalization and statistical analyses of microarray data was performed with the ‘oligo’ and ‘limma’ Bioconductor package in R software. The gene ontology and pathway analysis was performed in the InnateDB pathway analysis tool.

With FDR< 0.01 and log2 fold change 1.5 as cutoff criteria, 4269 transcripts were found to be differentially expressed in PBMCs among four contrast pairs (i.e. DL-24h vs DL-0h, Pi-24h vs Pi-0h, DL-0h vs Pi-0h and DL-24h vs Pi-24h) tested. The number of vaccine induced differentially expressed genes (DEG) was much higher (DL-0h vs DL-24h, DEG=2459) in Landrace pigs than that of Pietrain pigs (Pi-24h vs Pi-0h, DEG=291). Before vaccination, 3255 genes showed differential expression between DL and Pi (DL-0h vs Pi-0h) which indicated the genetic variation between two breeds. After 24 h of PRRSV vaccination, 1046 genes were over expressed in Landrace pig compared to Pietrain (DL-24h vs Pi-24h) which indicated the breed differences in vaccine responsiveness as well. The top ten biological pathways significantly affected by genes differentially expressed in four contrast pairs tested includes Cytokine signaling in immune system, Pathway in cancer, GPCR signaling, JAK STAT signaling, Interferon signaling, Autoimmune thyroid disease, Natural killer cell mediated cytotoxicity, Hepatitis C, Toll-like receptor signaling pathway and RIG-like receptor signaling pathway. Majority of the pathways are linked to immune response function.

These findings provided an insight into the gene expression changes associated with innate immune response to PRRSV vaccination between German Landrace and Pietrain pigs. This study revealed that German Landrace pigs showed greater transcriptional responses to PRRSV vaccine in peripheral blood compared to the Pietrain pigs.

Disclosure of Interest: None Declared.