Abstract
Porcine reproductive and respiratory syndrome (PRRS) caused by PRRS virus (PRRSV) is an infectious disease characterized by severe reproductive deficiency in pregnant sows, typical respiratory symptoms in piglets, and high mortality rate of piglets. In this study, we employed an Affymetrix microarray chip to compare the gene expression profiles of lung tissue samples from Dapulian (DPL) pigs (a Chinese indigenous pig breed) and Duroc×Landrace×Yorkshire (DLY) pigs after infection with PRRSV. During infection with PRRSV, the DLY pigs exhibited a range of clinical features that typify the disease, whereas the DPL pigs showed only mild signs of the disease. Overall, the DPL group had a lower percentage of CD4+ cells and lower CD4+/CD8+ratios than the DLY group (p<0.05). For both IL-10 and TNF-α, the DLY pigs had significantly higher levels than the DPL pigs (p<0.01). The DLY pigs have lower serum IFN-γ levels than the DPL pigs (p<0.01). The serum IgG levels increased slightly from 0 dpi to 7 dpi, and peaked at 14 dpi (p<0.0001). Microarray data analysis revealed 16 differentially expressed (DE) genes in the lung tissue samples from the DLY and DPL pigs (q≤5%), of which LOC100516029 and LOC100523005 were up-regulated in the PRRSV-infected DPL pigs, while the other 14 genes were down-regulated in the PRRSV-infected DPL pigs compared with the PRRSV-infected DLY pigs. The mRNA expression levels of 10 out of the 16 DE genes were validated by real-time quantitative RT-PCR and their fold change was consistent with the result of microarray data analysis. We further analyzed the mRNA expression level of 8 differentially expressed genes between the DPL and DLY pigs for both uninfected and infected groups, and found that TF and USP18 genes were important in underlying porcine resistance or susceptibility to PRRSV.
Highlights
Porcine reproductive and respiratory syndrome (PRRS), known as blue-ear pig disease, is a widespread infectious disease caused by porcine reproductive and respiratory syndrome virus (PRRSV), which is characterized by severe reproductive deficiency in pregnant sows, typical respiratory symptoms in pigs of all ages, increased susceptibility to secondary bacterial infection, and high mortality rate of piglets [1,2,3]
These pigs were free from PRRSV, porcine circovirus type 2 (PCV2), pseudorabies virus (PRV), and classical swine fever virus (CSFV) as determined by ELISA tests for serum antibodies; the absence of PRRSV was confirmed by real-time quantitative reverse transcription PCR
Comparison of DE Gene mRNA Expressions in Uninfected and Infected DPL and DLY Pigs In addition, we analyzed the mRNA expression level of 8 out of 67 genes which are differentially expressed at significance level 0.01 between the DPL and DLY pigs for both uninfected and infected groups
Summary
Porcine reproductive and respiratory syndrome (PRRS), known as blue-ear pig disease, is a widespread infectious disease caused by porcine reproductive and respiratory syndrome virus (PRRSV), which is characterized by severe reproductive deficiency in pregnant sows, typical respiratory symptoms in pigs of all ages, increased susceptibility to secondary bacterial infection, and high mortality rate of piglets [1,2,3]. Experimental PRRSV challenge infections in Duroc, Hampshire and Meishan pigs revealed that the latter breed had significantly less PRRSV antigen in their lungs than the other breeds, suggesting that differences in the severity and distribution of PRRSV-induced lesions and normal serum antibody responses to PRRSV may be influenced, at least in part, by genetic factors [9] Another two independent studies indicated that different pig breeds or lines responded differently to PRRSV infection, while analysis of the serum cytokine levels confirmed gene expression differences in the spleens and bronchial lymph nodes of these pigs [10,11]. Our previous study revealed differences in the PRRSV copy number and NMMHC-IIA and CD163 mRNA expression levels between virus infected Dapulian (DPL) and Duroc6Landrace6Yorkshire (DLY) pigs [12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
