Jasim Uddin

Porcine reproductive and respiratory syndrome (PRRS) is a devastating viral disease affecting swine industry worldwide. The innate immune response to PRRS virus (PRRSV) infection varies among pig breeds. 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. For this we used 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 24 h after PRRSV vaccination from three female piglets of four weeks age. With FDR < 0.01 and log2 fold change 1.5 as cutoff criteria, 4269 transcripts were found to be differentially expressed among four contrast pairs tested (DL-24h v. DL-0h, Pi-24h v. Pi-0h, DL-0h v. Pi-0h and DL-24h v. Pi-24h). The number of vaccine induced differentially expressed genes (DEG) was much higher (DL-0h v. DL-24h, DEG = 2459) in DL pigs than that of Pi pigs (Pi-24h v. Pi-0h, DEG = 291). Before vaccination, 3255 genes showed differential expression between DL and Pi (DL-0h v. Pi-0h) which indicated the genetic variation between two breeds. After 24 h of PRRSV vaccination, 1046 genes were overexpressed in DL pig compared to Pi (DL-24h v. Pi-24h) which indicated the breed differences in vaccine responsiveness. The top most biological pathways enriched by differentially expressed genes are linked to immune response function e.g.: cytokine signalling in immune system, GPCR signalling, JAK-STAT signalling or interferon signalling. The network enrichment analysis identified STAT1, MMS19, RPA2, BAD, UCHL5 and APC as potential regulatory genes for the functional network of PRRSV vaccine response specific for DL and FOXO3, IRF2, ADRBK1, MTOR and EIF3I genes for Pi pigs. SLC9A2, BAG3, RRS1, DCTN3, BUD31, ARPC1B and ATP5J2 were found to be the most potential hubs of the shared network of transcriptome response in PBMCs of both DL and Pi pigs. In conclusion, DL pigs differ greatly from that of Pi in terms of PBMCs transcriptome profiles after PRRSV vaccination.

Following severe flooding in eastern Australia in 2011 an equine West Nile virus (WNV) induced encephalitis epidemic ensued with ~1000 horses affected and mortality of 10-15%. A new strain, WNVNSW2011 was isolated. Infections with WNV are mostly (>80%) mild to subclinical, likely because of a virus-limiting innate response in the peripheral blood leukocytes and draining lymph nodes. Therefore, we have investigated the transcripts of peripheral blood mononuclear cells (PBMCs) that might restrict the virus as the first line defence. PBMCs were collected from intra-dermally WNVNSW2011-infected rabbits (n=12) and horses (n=3) on the day before infection (D-1), and various days post infection (DPI). Blood cells were also collected from control (n=3) rabbits and horses. Transcripts of interest including cytokines, Toll-like receptors (TLR), and TLR-associated downstream genes were quantified using quantitative RT- PCR. Interferon α & β, IL6, IL22, CXCL10, PTX3, TLR1, TLR3, TLR6, STAT1, MyD88, TRAF3, IRF7, IRF9, IFIT2, and NOD2 mRNA expressions were upregulated on 1 DPI, and TLR3 and IRF3 remained highly upregulated till 3 DPI in rabbits. IFNα & β, IL22, PTX3, TLR7 mRNA expression was upregulated on days 1-7 DPI in horses. TLR1-3, TLR8 & TRAF3 mRNA expression was upregulated between 11-18 DPI, while MyD88, STST1, STAT2 & ISG15 mRNA expression was upregulated at 7 DPI in horses. Both infection pathobiology in vivo, and transcriptome responses of PBMCs to WNV infection in vitro already established rabbit as an appropriate model for subclinical WNV-infection1-6. This study further showed that transcriptome kinetics of experimentally infected-rabbit PBMC were similar to that of horse cells. Furthermore, immediate recognition of virus by TLRs and rapid response of IFNs might be the limiting peripheral cellular factors contributing in subclinical features of the Australian WNV-strain.