The effects of vaccination and WUR genotype on blood gene expression response to co-infection with PRRSV and PCV2 in pigs

Authors: DONG, QIAN - Iowa State University; Lunney, Joan; NGUYEN, Y - Iowa State University; TUGGLE, CK - Iowa State University; REECY, JAMES - Iowa State University; ROWLAND, RAYMOND - Kansas State University; DEKKERS, JACK - Iowa State University

Submitted to: World Congress of Genetics Applied in Livestock Production
Publication Type: Proceedings
Publication Acceptance Date: 11/1/2017
Publication Date: 2/11/2018
Citation: Dong, Q., Lunney, J.K., Nguyen, Y., Tuggle, C., Reecy, J., Rowland, R.R., Dekkers, J. 2018. The effects of vaccination and WUR genotype on blood gene expression response to co-infection with PRRSV and PCV2 in pigs. World Congress of Genetics Applied in Livestock Production. 11:993.

Interpretive Summary: Co-infection with PRRSV and PCV2 is a useful model for PRRS and PCV AD in the field, with PRRSV enhancing replication of PCV2. Our objectives were to evaluate the effect of vaccination with a PRRS modified live virus (MLV) and of genotype at a marker (WUR), that is associated with 1RRs resistance, on the blood transcriptome response of commercial nursery pigs that were exper1mentally co-infected with both PRRSV and PCV2 and preselected to equally represent AA and Pm WUR genotypes. [n total, 191 blood samples collected from 14 vaccinated and 14 non­vaccinated piglets at 4, 7, 11, and 14 days post vaccination (dpv) [Vac pigs only] and at 0 (=28 dpv), 4, 7, 11, 14, and 28 days post coinfection (dpi) were selected for transcriptome analysis using QuantSeq. Differential expression analysis was conducted separately for each time point. No DEGs were identified (q less than or equal to 0.2) for the effect of WUR genotype or for the interaction between WUR genotype and VacStatus at any time point. For VacStatus, DEGs (q less than or equal to 0.2) were only identified at 4 dpi (40 DEGs) and 7 dpi (63 DEGs). Using lngenuity Pathway Analysis, the DEGs for VacStatus included SIGLECl (CDJ69), MXJ, MX2, CXCLI0, and FCGRlA, which were significantly less expressed in Vac pigs and play a role in leukocyte migration, quantity of blood cells, inflammatory response (on 7 dpi only), viral infection, and immune response. Based on WGCNA and DA VTD results, genes in gene modules that were significantly less expressed in the Vac groups participate in defense response to virus, negative regulation of viral genome replication, innate immune response on 4 dpi and cytokine-cytokine receptor interaction, chemokine signaling pathway, immune response on 7 dpi. Taken together, this study indicates that having less SlGLECl, a PRRSV receptor expressed on macrophages, may induce fewer PRRSV infected cells, which then triggers lower innate immune response and less inhibition of PCV2b viral infection in Vac pigs, and that WUR genotype and the interaction between WUR genotypes and VacStatus may not have a large effect on the blood gene expression following vaccination and co-infection.

Technical Abstract: Co-infection with PRRSV and PCV2 is a useful model for PRRS and PCVAD in the field, with PRRSV enhancing replication of PCV2. Our objectives were to evaluate the effect of vaccination with a PRRS modified live virus (MLV) and of genotype at a marker (WUR), that is associated with PRRS resistance, on the blood transcriptome response of commercial nursery pigs that were experimentally co-infected with both PRRSV and PCV2 and preselected to equally represent AA and AB WUR genotypes. In total, 191 blood samples collected from 14 vaccinated and 14 nonvaccinated piglets at 4, 7, 11, and 14 days post vaccination (dpv) [Vac pigs only] and at 0 (=28 dpv), 4, 7, 11, 14, and 28 days post coinfection (dpi) were selected for transcriptome analysis using QuantSeq. Differential expression analysis was conducted separately for each time point. No DEGs were identified (q=0.2) for the effect of WUR genotype or for the interaction between WUR genotype and VacStatus at any time point. For VacStatus, DEGs (q=0.2) were only identified at 4 dpi (40 DEGs) and 7 dpi (63 DEGs). Using Ingenuity Pathway Analysis, the DEGs for VacStatus included SIGLEC1 (CD169), MX1, MX2, CXCL10, and FCGR1A, which were significantly less expressed in Vac pigs and play a role in leukocyte migration, quantity of blood cells, inflammatory response (on 7 dpi only), viral infection, and immune response. Based on WGCNA and DAVID results, genes in gene modules that were significantly less expressed in the Vac groups participate in defense response to virus, negative regulation of viral genome replication, innate immune response on 4 dpi and cytokine-cytokine receptor interaction, chemokine signaling pathway, immune response on 7 dpi. Taken together, this study indicates that having less SIGLEC1, a PRRSV receptor expressed on macrophages, may induce fewer PRRSV infected cells, which then triggers lower innate immune response and less inhibition of PCV2b viral infection in Vac pigs, and that WUR genotype and the interaction between WUR genotypes and VacStatus may not have a large effect on the blood gene expression following vaccination and co-infection.