Analysis of the Swine Tracheobronchial Lymph Node Transcriptomic Response to Infection with PRRSV20 November 2012
Researchers in the US have found that the different gene profiles detected in a highly pathogenic strain of the porcine reproductive and respiratory syndrome virus (PRRSV) from China are consistent with its increased pathogenicity.
PRRSV is a major pathogen of swine worldwide, report Laura C. Miller of the US National Animal Disease Center-USDA-ARS and co-authors there and at Iowa State University in a paper published in BMC Veterinary Research recently.
They explain that the emergence in 2006 of a novel highly pathogenic PRRSV (HP-PRRSV) isolate in China necessitated a comparative investigation into the host transcriptome response in tracheobronchial lymph nodes (TBLN) 13 days post-infection with HP-PRRSV rJXwn06, PRRSV strain VR-2332 or sham inocula. RNA from each was prepared for next-generation sequencing. Amplified library constructs were directly sequenced and a list of sequence transcripts and counts was generated using an RNAseq analysis pipeline to determine differential gene expression. Transcripts were annotated and relative abundance was calculated based upon the number of times a given transcript was represented in the library.
Major changes in transcript abundance occurred in response to infection with either PRRSV strain, each with over 630 differentially expressed transcripts. The largest increase in transcript level for either virus versus sham-inoculated controls were three serum amyloid A2 acute-phase isoforms. However, the degree of up or down-regulation of transcripts following infection with HP-PRRSV rJXwn06 was greater than transcript changes observed with US PRRSV VR-2332. Also, of 632 significantly altered transcripts within the HP-PRRSV rJXwn06 library 55 were up-regulated and 69 were down-regulated more than three-fold, whilst in the US PRRSV VR-2332 library only four transcripts were up-regulated and 116 were down-regulated more than three-fold.
Miller and her co-authors concluded that the magnitude of differentially expressed gene profiles detected in HP-PRRSV rJXwn06 infected pigs as compared to VR-2332 infected pigs was consistent with the increased pathogenicity of the HP-PRRSV in vivo.
Miller L.C., D. Fleming, A. Arbogast, D.O. Bayles, B. Guo, K.M. Lager, J.N. Henningson, S.N. Schlink, H-C. Yang, K.S. Faaberg and M.E. Kehrli. 2012. Analysis of the swine tracheobronchial lymph node transcriptomic response to infection with a Chinese highly pathogenic strain of porcine reproductive and respiratory syndrome virus. BMC Veterinary Research, 8:208. doi:10.1186/1746-6148-8-208
Further ReadingYou can view the full report (as a provisional PDF) by clicking here.
Find out more information on Porcine Reproductive Respiratory Syndrome (PRRS) by clicking here.