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United States Department of Agriculture

Agricultural Research Service

Research Project: GENE EXPRESSION IN LYMPH NODES OF PRRSV-INFECTED PIGS Project Number: 3625-32000-088-28
Project Type: Reimbursable

Start Date: Nov 01, 2008
End Date: May 01, 2011

Objective:
Acquire a better understanding of PRRS disease through a deeper knowledge of gene expression changes that occur in pulmonary lymph nodes during acute comparative PRRSV strain infections.

Approach:
Eighty weaned pigs will be randomly allotted to one of 4 equal treatment groups: Group 1 sham inoculated control, Group 2 PRRSV challenge, Group 3 PCV2 challenge, or Group 4 SIV-challenge. On 0 days post-infection (dpi) pigs will receive an intranasal challenge 1 x 10**5 cell culture infectious dose 50% (CCID50) per pig according to their assigned group. Five pigs from each group will be euthanized and necropsied on 1, 3, 6, and 14 dpi. At necropsy, lungs will be scored for gross lesions. Bronchioalveolar lavage fluid (BALF) and tracheal-bronchial lymph nodes (TBLN) will be collected. Sections of TBLN and lung will be placed into formalin for histopathology. All 0, 1, 3, 6, and 14 dpi sera and BALF will be tested for respective virus. Total RNA will be collected from TBLN, pooled for each group and timepoint to make 16 libraries, for analysis with a whole-genome expression analysis platform. The data generated will undergo image analysis, base calling, and standard filtering to generate a list of sequence tags and counts. Multidimensional statistical tests will be applied to determine which changes in tag abundance are significant. Tags will be annotated with genomic information and differential gene expression analyzed. The experimental results will be integrated with previous studies to develop a robust model of swine respiratory virus infection. For select genes of interest, significant changes will be validated by real-time RT-PCR, and changes in transcript abundance will be mapped to known metabolic, signaling and other pathways/networks.

Last Modified: 11/26/2014
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